/* ==========================================================================
   一笔画 · 连线闯关
   独立设计系统：宣纸暖白 / 墨色 / 朱砂；深色为「夜航」配色
   ========================================================================== */

:root {
    color-scheme: light;

    --bg: #f3eee2;
    --bg-deep: #e7dfcd;
    --panel: #fffdf7;
    --panel-soft: #f9f4e9;
    --panel-tint: #f4eddd;

    --ink: #1d2a2e;
    --ink-2: #4b595d;
    --ink-3: #7b888a;
    --line: #e0d7c4;
    --line-strong: #c9bda2;

    --accent: #b3451f;
    --accent-2: #c96034;
    --accent-soft: #f5ded1;
    --accent-ink: #8e3314;
    --jade: #2b6b5a;
    --jade-soft: #d9e9e1;
    --gold: #b0802f;
    --gold-soft: #f0e2c4;

    --edge-rest: #a89a7f;
    --node-core: #253238;
    --node-done: #2b6b5a;

    --shadow-sm: 0 1px 2px rgba(29, 42, 46, .05), 0 10px 24px -16px rgba(29, 42, 46, .35);
    --shadow-md: 0 2px 4px rgba(29, 42, 46, .04), 0 24px 48px -28px rgba(29, 42, 46, .42);
    --shadow-lg: 0 8px 16px rgba(29, 42, 46, .06), 0 48px 96px -48px rgba(29, 42, 46, .5);

    --radius-sm: 12px;
    --radius: 18px;
    --radius-lg: 26px;

    --font-sans: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
    --font-serif: "Songti SC", "STSong", "Noto Serif SC", "Source Han Serif SC", ui-serif, Georgia, serif;
    --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", monospace;

    --top-h: 64px;
}

html[data-theme="dark"] {
    color-scheme: dark;

    --bg: #0b1214;
    --bg-deep: #080e10;
    --panel: #131d1e;
    --panel-soft: #172324;
    --panel-tint: #1b2829;

    --ink: #eaf0ec;
    --ink-2: #a9b7b2;
    --ink-3: #8b9c96;
    --line: #263534;
    --line-strong: #354846;

    --accent: #ef8a58;
    --accent-2: #f3a878;
    --accent-soft: #35211a;
    --accent-ink: #ffc4a4;
    --jade: #6fd2af;
    --jade-soft: #16302a;
    --gold: #e2b866;
    --gold-soft: #332a17;

    --edge-rest: #465a53;
    --node-core: #dce6e0;
    --node-done: #6fd2af;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4), 0 12px 28px -18px rgba(0, 0, 0, .8);
    --shadow-md: 0 2px 6px rgba(0, 0, 0, .4), 0 28px 56px -30px rgba(0, 0, 0, .9);
    --shadow-lg: 0 10px 24px rgba(0, 0, 0, .5), 0 56px 112px -56px rgba(0, 0, 0, 1);
}

* { box-sizing: border-box; }

html {
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: var(--font-sans);
    font-size: 15px;
    line-height: 1.7;
    color: var(--ink);
    background-color: var(--bg);
    background-image:
        radial-gradient(900px 520px at 12% -8%, rgba(179, 69, 31, .10), transparent 62%),
        radial-gradient(760px 480px at 88% 4%, rgba(43, 107, 90, .10), transparent 60%),
        radial-gradient(circle at 1px 1px, rgba(29, 42, 46, .055) 1px, transparent 0);
    background-size: auto, auto, 22px 22px;
    background-attachment: fixed;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

html[data-theme="dark"] body {
    background-image:
        radial-gradient(900px 520px at 12% -8%, rgba(239, 138, 88, .10), transparent 62%),
        radial-gradient(760px 480px at 88% 4%, rgba(111, 210, 175, .08), transparent 60%),
        radial-gradient(circle at 1px 1px, rgba(234, 240, 236, .05) 1px, transparent 0);
}

h1, h2, h3, p, ul, ol, dl, dd, figure { margin: 0; }
ul, ol { padding: 0; list-style: none; }
button, input { font: inherit; color: inherit; }
button { cursor: pointer; background: none; border: 0; }
a { color: inherit; text-decoration: none; }
svg { display: block; }
img { max-width: 100%; }

::selection { background: var(--accent-soft); color: var(--accent-ink); }

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
    border-radius: 6px;
}

.os-skip {
    position: fixed;
    left: 16px;
    top: -60px;
    z-index: 200;
    padding: 10px 16px;
    border-radius: 10px;
    background: var(--ink);
    color: var(--bg);
    font-size: 13px;
    transition: top .2s ease;
}
.os-skip:focus { top: 12px; }

.os-sr {
    position: absolute;
    width: 1px; height: 1px;
    margin: -1px; padding: 0;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
}

/* ==========================================================================
   页头 / 页脚改用站内公共组件（layouts.app → partials.header / footer）
   这里只保留棋盘内的图标工具按钮
   ========================================================================== */

.os-tool-icon { padding: 7px 9px; }
.os-tool-icon svg { width: 17px; height: 17px; }
.os-tool-icon .ic-off,
.os-tool-icon.is-muted .ic-on { display: none; }
.os-tool-icon.is-muted .ic-off { display: block; }

/* 「一键避险」悬浮球在右下角会压住棋盘工具栏；快捷键（双击空格）仍然可用 */
.evade-fab { display: none !important; }

.os-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 7px;
    padding: 9px 16px;
    border-radius: 11px;
    border: 1px solid transparent;
    font-size: 13.5px;
    font-weight: 600;
    letter-spacing: .01em;
    white-space: nowrap;
    transition: transform .18s ease, background-color .18s ease, border-color .18s ease, box-shadow .18s ease, color .18s ease;
}
.os-btn svg { width: 17px; height: 17px; flex: none; }
.os-btn:active { transform: translateY(1px) scale(.995); }

.os-btn-primary {
    color: #fff8f1;
    background: linear-gradient(140deg, #c1552b, #a2381a);
    box-shadow: 0 1px 0 rgba(255, 255, 255, .18) inset, 0 8px 20px -12px rgba(162, 56, 26, .9);
}
.os-btn-primary:hover {
    background: linear-gradient(140deg, #cd5f33, #ac3d1d);
    box-shadow: 0 1px 0 rgba(255, 255, 255, .22) inset, 0 12px 26px -12px rgba(162, 56, 26, .95);
}
html[data-theme="dark"] .os-btn-primary {
    color: #20100a;
    background: linear-gradient(140deg, #f5a374, #e07a49);
    box-shadow: 0 1px 0 rgba(255, 255, 255, .3) inset, 0 10px 24px -14px rgba(240, 138, 88, .9);
}

.os-btn-ghost {
    color: var(--ink);
    background: var(--panel);
    border-color: var(--line);
    box-shadow: var(--shadow-sm);
}
.os-btn-ghost:hover { border-color: var(--line-strong); background: var(--panel-soft); }

.os-btn-quiet {
    color: var(--ink-2);
    background: transparent;
    border-color: color-mix(in srgb, var(--line) 80%, transparent);
}
.os-btn-quiet:hover { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 45%, var(--line)); background: var(--panel); }

.os-btn-danger {
    color: #fff;
    background: #b3382f;
}
.os-btn-danger:hover { background: #c24136; }

.os-btn-lg { padding: 13px 22px; font-size: 15px; border-radius: 13px; }
.os-btn-sm { padding: 8px 13px; font-size: 13px; border-radius: 10px; }

.os-text-btn {
    font-size: 12.5px;
    font-weight: 600;
    color: var(--accent);
    padding: 4px 2px;
    border-radius: 6px;
    border-bottom: 1px solid transparent;
    transition: border-color .18s ease, color .18s ease;
}
.os-text-btn:hover { border-color: color-mix(in srgb, var(--accent) 60%, transparent); }
.os-text-danger { color: var(--ink-3); font-weight: 500; }
.os-text-danger:hover { color: #b3382f; }

/* ==========================================================================
   主区域 / 首屏
   ========================================================================== */

.os-main {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

.os-hero {
    display: grid;
    grid-template-columns: minmax(0, .92fr) minmax(0, 1.28fr);
    gap: clamp(24px, 4vw, 56px);
    align-items: center;
    padding: clamp(22px, 3.4vw, 40px) 0 8px;
}

.os-eyebrow {
    display: flex;
    width: fit-content;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: .16em;
    color: var(--accent);
    text-transform: uppercase;
}
.os-eyebrow-dot {
    width: 6px; height: 6px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 14%, transparent);
}

.os-hero h1 {
    font-family: var(--font-serif);
    font-size: clamp(40px, 4.6vw, 62px);
    line-height: 1.06;
    letter-spacing: .1em;
    font-weight: 700;
    margin: 14px 0 0;
    color: var(--ink);
    position: relative;
    display: block;
}
.os-hero h1 span {
    display: block;
    margin-top: 12px;
    font-family: var(--font-sans);
    font-size: clamp(14px, 1.35vw, 17px);
    font-weight: 600;
    letter-spacing: .5em;
    color: var(--accent);
    padding-left: 2px;
}

.os-sub {
    margin-top: 18px;
    max-width: 33em;
    font-size: 15.5px;
    line-height: 1.85;
    color: var(--ink-2);
}

.os-hero-cta {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 24px;
}

.os-hero-points {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 18px;
    margin-top: 20px;
    font-size: 12.5px;
    color: var(--ink-3);
}
.os-hero-points li { display: inline-flex; align-items: center; gap: 7px; }
.os-hero-points li::before {
    content: "";
    width: 5px; height: 5px;
    border-radius: 50%;
    background: var(--jade);
    opacity: .75;
}

.os-hero-total {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 26px;
    padding-top: 20px;
    border-top: 1px dashed var(--line);
    max-width: 360px;
}
.os-total-stars {
    font-family: var(--font-serif);
    font-size: 40px;
    line-height: 1;
    color: var(--gold);
    letter-spacing: -.02em;
    font-variant-numeric: tabular-nums;
}
.os-total-label {
    display: flex;
    flex-direction: column;
    font-size: 12.5px;
    color: var(--ink-2);
    line-height: 1.5;
}
.os-total-label small { color: var(--ink-3); font-size: 11.5px; }

/* ==========================================================================
   棋盘卡片
   ========================================================================== */

.os-board-card {
    position: relative;
    padding: 16px;
    border-radius: var(--radius-lg);
    background:
        linear-gradient(180deg, color-mix(in srgb, var(--panel) 92%, transparent), var(--panel));
    border: 1px solid var(--line);
    box-shadow: var(--shadow-md);
}
.os-board-card::before {
    content: "";
    position: absolute;
    inset: 6px;
    border-radius: calc(var(--radius-lg) - 7px);
    border: 1px solid color-mix(in srgb, var(--line) 45%, transparent);
    pointer-events: none;
}

.os-board-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 6px 6px 12px;
    position: relative;
    z-index: 1;
}

.os-level-meta { display: flex; align-items: center; gap: 9px; min-width: 0; flex-wrap: wrap; }

.os-tier-badge {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 3px 9px;
    border-radius: 999px;
    font-size: 11.5px;
    font-weight: 700;
    letter-spacing: .04em;
    color: var(--accent-ink);
    background: var(--accent-soft);
    border: 1px solid color-mix(in srgb, var(--accent) 20%, transparent);
}
.os-tier-badge[data-tier="medium"] {
    color: #7a5312;
    background: var(--gold-soft);
    border-color: color-mix(in srgb, var(--gold) 26%, transparent);
}
html[data-theme="dark"] .os-tier-badge[data-tier="medium"] { color: #ecc887; }
.os-tier-badge[data-tier="hard"] {
    color: #245c4e;
    background: var(--jade-soft);
    border-color: color-mix(in srgb, var(--jade) 26%, transparent);
}
html[data-theme="dark"] .os-tier-badge[data-tier="hard"] { color: #8fe2c4; }

.os-level-name {
    font-family: var(--font-serif);
    font-size: 17px;
    font-weight: 700;
    letter-spacing: .03em;
    white-space: nowrap;
}
.os-level-rule {
    font-size: 11.5px;
    color: var(--ink-3);
    padding-left: 9px;
    border-left: 1px solid var(--line);
    white-space: nowrap;
}
.os-live-stars {
    display: inline-flex;
    flex: none;
    gap: 1px;
    line-height: 1;
    letter-spacing: 0;
    color: var(--line-strong);
}
.os-live-stars .is-on { color: var(--gold); }

.os-meters { display: flex; align-items: center; gap: 14px; }
.os-meter { display: flex; flex-direction: column; align-items: flex-end; line-height: 1.2; }
.os-meter b {
    font-family: var(--font-mono);
    font-size: 15px;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    letter-spacing: -.01em;
}
.os-meter small { font-size: 10.5px; color: var(--ink-3); letter-spacing: .06em; }

.os-progress-line {
    position: relative;
    z-index: 1;
    height: 3px;
    margin: 0 6px 10px;
    border-radius: 3px;
    background: var(--panel-tint);
    overflow: hidden;
}
.os-progress-line i {
    display: block;
    height: 100%;
    width: 0;
    border-radius: 3px;
    background: linear-gradient(90deg, var(--accent), var(--jade));
    transition: width .3s cubic-bezier(.2, .7, .3, 1);
}

.os-board-stage {
    position: relative;
    z-index: 1;
    width: 100%;
    aspect-ratio: 1.16;
    max-height: min(58vh, 540px);
    border-radius: var(--radius);
    background:
        radial-gradient(120% 90% at 50% 0%, color-mix(in srgb, var(--panel-soft) 90%, transparent), transparent 70%),
        linear-gradient(180deg, color-mix(in srgb, var(--panel-tint) 55%, transparent), color-mix(in srgb, var(--panel-soft) 30%, transparent));
    border: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
    overflow: hidden;
    touch-action: none;
    user-select: none;
    -webkit-user-select: none;
}
.os-board-stage::after {
    content: "";
    position: absolute;
    inset: 0;
    pointer-events: none;
    background-image:
        linear-gradient(color-mix(in srgb, var(--line) 30%, transparent) 1px, transparent 1px),
        linear-gradient(90deg, color-mix(in srgb, var(--line) 30%, transparent) 1px, transparent 1px);
    background-size: 44px 44px;
    opacity: .5;
    mask-image: radial-gradient(120% 100% at 50% 40%, #000 20%, transparent 78%);
    -webkit-mask-image: radial-gradient(120% 100% at 50% 40%, #000 20%, transparent 78%);
}

.os-stage-glow {
    position: absolute;
    width: 46%;
    aspect-ratio: 1;
    right: -14%;
    top: -18%;
    border-radius: 50%;
    background: radial-gradient(circle, color-mix(in srgb, var(--jade) 18%, transparent), transparent 68%);
    pointer-events: none;
}

.os-svg {
    position: relative;
    z-index: 2;
    width: 100%;
    height: 100%;
    display: block;
    touch-action: none;
    overflow: visible;
}

/* SVG 内部：连线 */
.os-svg .edge {
    stroke: var(--edge-rest);
    stroke-width: 2;
    stroke-dasharray: 4 8;
    stroke-linecap: round;
    opacity: .92;
    vector-effect: non-scaling-stroke;
    transition: opacity .25s ease, stroke-width .2s ease, stroke .2s ease;
}
.os-svg .edge.is-used {
    stroke: url(#osTrailGrad);
    stroke-width: 4.2;
    stroke-dasharray: none;
    opacity: 1;
    filter: url(#osGlow);
    animation: osEdgeIn .3s cubic-bezier(.2, .8, .3, 1) both;
}
.os-svg .edge.is-hint {
    stroke: var(--gold);
    stroke-width: 3.6;
    stroke-dasharray: 2 7;
    opacity: 1;
    animation: osHintPulse 1.1s ease-in-out infinite;
}
.os-svg .edge.is-dim { opacity: .3; }
.os-svg .edge.is-undo-hint {
    stroke: var(--accent);
    stroke-width: 4.6;
    stroke-dasharray: 1 7;
    opacity: 1;
    animation: osUndoPulse .9s ease-in-out infinite;
}
@keyframes osUndoPulse {
    0%, 100% { opacity: .4; }
    50% { opacity: 1; }
}

/* 画线：从起笔端「长」出来，配一笔亮头 + 收笔火星 */
@keyframes osEdgeIn {
    0% { opacity: 0; stroke-width: 8.5; }
    55% { opacity: 1; stroke-width: 6; }
    100% { opacity: 1; stroke-width: 4.2; }
}
@keyframes osHintPulse {
    0%, 100% { opacity: .35; }
    50% { opacity: 1; }
}

/* SVG 内部：节点 */
.os-svg .node { cursor: pointer; }
.os-svg .node .halo {
    fill: var(--panel);
    stroke: var(--line-strong);
    stroke-width: 1.6;
    vector-effect: non-scaling-stroke;
    transition: stroke .2s ease, fill .2s ease, r .2s ease;
}
.os-svg .node .core {
    fill: var(--node-core);
    transition: fill .2s ease, transform .2s ease;
    transform-box: fill-box;
    transform-origin: center;
}
.os-svg .node .pulse {
    fill: none;
    stroke: var(--accent);
    stroke-width: 1.4;
    vector-effect: non-scaling-stroke;
    opacity: 0;
}
.os-svg .node.is-done .core { fill: var(--node-done); }
.os-svg .node.is-done .halo { stroke: color-mix(in srgb, var(--node-done) 40%, var(--line-strong)); }
.os-svg .node.is-start .halo { stroke: var(--jade); stroke-width: 2; }
.os-svg .node.is-odd .halo { fill: var(--accent-soft); stroke: var(--accent); stroke-width: 2; }
.os-svg .node.is-odd .core { fill: var(--accent); }
.os-svg .node.is-current .halo { stroke: var(--accent); stroke-width: 2.4; }
.os-svg .node.is-current .core { fill: var(--accent); }
.os-svg .node.is-current .pulse { animation: osPulse 1.6s ease-out infinite; opacity: .9; }
.os-svg .node.is-hint .halo {
    stroke: var(--gold);
    stroke-width: 2.8;
    fill: var(--gold-soft);
}
.os-svg .node.is-hint .core { fill: var(--gold); }
.os-svg .node.is-hint .pulse { stroke: var(--gold); animation: osPulse 1.2s ease-out infinite; opacity: .8; }
/* 画进死路后，把两个合法起笔点亮出来（不提前剧透） */
.os-svg .node.is-odd-flash .halo { stroke: var(--gold); stroke-width: 3; fill: var(--gold-soft); }
.os-svg .node.is-odd-flash .core { fill: var(--gold); }
.os-svg .node.is-odd-flash .pulse { stroke: var(--gold); opacity: .85; animation: osPulse 1.2s ease-out 3; }

.os-svg .node.is-near .halo { stroke: var(--jade); stroke-width: 2.2; }
.os-svg .node.is-near .core { transform: scale(1.18); }

/* 轨迹渐变（跟随主题） */
.os-svg .gs-a { stop-color: var(--accent); }
.os-svg .gs-b { stop-color: var(--gold); }
.os-svg .gs-c { stop-color: var(--jade); }

@keyframes osPulse {
    0% { r: 15; opacity: .85; }
    70% { r: 27; opacity: 0; }
    100% { r: 27; opacity: 0; }
}

@media (hover: hover) {
    .os-svg .node:hover .halo { stroke: var(--accent); stroke-width: 2.2; }
    .os-svg .node:hover .core { transform: scale(1.14); }
}

.os-board-stage.is-enter .os-svg { animation: osBoardIn .5s cubic-bezier(.2, .8, .3, 1) both; }
@keyframes osBoardIn {
    from { opacity: 0; transform: scale(.965); }
    to { opacity: 1; transform: scale(1); }
}

.os-board-stage.is-shake { animation: osShake .28s ease-in-out; }
@keyframes osShake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    65% { transform: translateX(4px); }
}

/* 走错：棋盘红闪 + 节点抖动 + 红色叉号 */
.os-board-stage.is-error::before {
    content: "";
    position: absolute;
    inset: 0;
    z-index: 4;
    pointer-events: none;
    border-radius: inherit;
    box-shadow: inset 0 0 0 2px rgba(179, 56, 47, .65), inset 0 0 42px rgba(179, 56, 47, .28);
    animation: osErrorFlash .52s ease-out both;
}
@keyframes osErrorFlash {
    0% { opacity: .95; }
    55% { opacity: .45; }
    100% { opacity: 0; }
}

.os-svg .node.is-bad .halo {
    stroke: #b3382f;
    stroke-width: 3;
    fill: color-mix(in srgb, #b3382f 16%, var(--panel));
    animation: osNodeWobble .42s ease-in-out;
}
.os-svg .node.is-bad .core { fill: #b3382f; }
@keyframes osNodeWobble {
    0%, 100% { transform: translate(0, 0); }
    20% { transform: translate(-3px, 0); }
    45% { transform: translate(3px, 0); }
    70% { transform: translate(-2px, 0); }
}

/* 画线特效层 */
.os-svg .layer-fx { pointer-events: none; }
.os-svg .fx-comet {
    fill: var(--gold);
    filter: url(#osGlow);
    pointer-events: none;
}
.os-svg .fx-spark {
    fill: var(--accent-2);
    pointer-events: none;
}
.os-svg .fx-bad {
    stroke: #b3382f;
    stroke-width: 4;
    stroke-linecap: round;
    fill: none;
    pointer-events: none;
}
.os-svg .fx-bad-ring {
    fill: none;
    stroke: #b3382f;
    stroke-width: 2.4;
    opacity: .85;
    pointer-events: none;
}
.os-svg .fx-win-ring {
    fill: none;
    stroke: var(--jade);
    stroke-width: 2.6;
    pointer-events: none;
}

/* 拖拽中的实时笔迹：流动的虚线光带 + 光标火花 */
.os-svg .layer-live { pointer-events: none; }
.os-svg .live-line {
    stroke: var(--accent);
    stroke-width: 3.2;
    stroke-linecap: round;
    stroke-dasharray: 8 7;
    opacity: 0;
    filter: url(#osGlow);
    animation: osLiveDash .55s linear infinite;
    transition: opacity .12s ease, stroke .16s ease;
}
.os-svg .live-line.is-on { opacity: .8; }
.os-svg .live-line.is-snap {
    stroke: var(--gold);
    stroke-width: 4.2;
    stroke-dasharray: none;
    opacity: .95;
    animation: none;
}
.os-svg .live-dot {
    fill: var(--gold);
    opacity: 0;
    filter: url(#osGlow);
    transition: opacity .12s ease, fill .16s ease;
}
.os-svg .live-dot.is-on { opacity: 1; }
.os-svg .live-dot.is-snap { fill: var(--accent); r: 6.6; }
.os-svg .fx-trace { fill: var(--gold); pointer-events: none; }

@keyframes osLiveDash { to { stroke-dashoffset: -30; } }

@media (prefers-reduced-motion: reduce) {
    .os-svg .live-line { animation: none; }
}

.os-toast {
    position: absolute;
    left: 50%;
    bottom: 16px;
    z-index: 5;
    transform: translate(-50%, 8px);
    max-width: calc(100% - 32px);
    padding: 8px 14px;
    border-radius: 999px;
    background: color-mix(in srgb, var(--ink) 92%, transparent);
    color: var(--bg);
    font-size: 12.5px;
    line-height: 1.4;
    text-align: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity .2s ease, transform .2s ease;
    box-shadow: 0 8px 24px rgba(0, 0, 0, .18);
}
.os-toast.is-on { opacity: 1; transform: translate(-50%, 0); }
.os-toast.is-bad {
    background: color-mix(in srgb, #7d2b23 94%, transparent);
    color: #ffece6;
    box-shadow: 0 8px 24px rgba(125, 43, 35, .3);
}

.os-board-foot {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 12px 6px 4px;
    flex-wrap: wrap;
}

/* 灯泡提示：工具栏里的金色胶囊按钮 */
.os-tool.os-tool-bulb {
    position: relative;
    gap: 6px;
    padding: 7px 12px 7px 10px;
    color: var(--gold);
    background: color-mix(in srgb, var(--gold) 10%, var(--panel));
    border: 1px solid color-mix(in srgb, var(--gold) 36%, var(--line));
    font-weight: 700;
    animation: osBulbGlow 3.6s ease-in-out infinite;
}
.os-tool.os-tool-bulb:hover {
    color: var(--gold);
    background: color-mix(in srgb, var(--gold) 17%, var(--panel));
    border-color: color-mix(in srgb, var(--gold) 72%, var(--line));
}
.os-tool.os-tool-bulb svg { width: 16px; height: 16px; }
.os-tool.os-tool-bulb .os-tool-cost {
    color: var(--accent-ink);
    background: color-mix(in srgb, var(--accent) 14%, transparent);
    border-color: color-mix(in srgb, var(--accent) 26%, transparent);
}
.os-tool.os-tool-bulb.is-used {
    color: var(--ink-3);
    background: transparent;
    border-color: var(--line);
    animation: none;
}
.os-tool.os-tool-bulb.is-used .os-tool-cost {
    color: var(--ink-3);
    background: var(--panel-tint);
    border-color: var(--line);
}
.os-tool.os-tool-bulb.is-pulse .os-bulb-ring { animation: osBulbPing 1.5s ease-out 3; }
.os-tool.os-tool-bulb.is-flash { animation: osBulbFlash .6s ease-out; }
.os-bulb-ring {
    position: absolute;
    inset: -4px;
    border-radius: 999px;
    border: 1px solid color-mix(in srgb, var(--gold) 55%, transparent);
    opacity: 0;
    pointer-events: none;
}

@keyframes osBulbGlow {
    0%, 100% { box-shadow: 0 8px 20px -14px rgba(176, 128, 47, .95), 0 0 0 0 color-mix(in srgb, var(--gold) 32%, transparent); }
    50% { box-shadow: 0 8px 20px -12px rgba(176, 128, 47, 1), 0 0 0 6px color-mix(in srgb, var(--gold) 0%, transparent); }
}
@keyframes osBulbPing {
    0% { opacity: .85; transform: scale(.92); }
    80%, 100% { opacity: 0; transform: scale(1.22); }
}
@keyframes osBulbFlash {
    0% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--gold) 55%, transparent); }
    100% { box-shadow: 0 0 0 16px color-mix(in srgb, var(--gold) 0%, transparent); }
}

.os-tools { display: flex; align-items: center; gap: 4px; }
.os-tool {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 7px 11px;
    border-radius: 9px;
    font-size: 12.5px;
    font-weight: 600;
    color: var(--ink-2);
    border: 1px solid transparent;
    transition: background-color .16s ease, color .16s ease, border-color .16s ease;
}
.os-tool svg { width: 15px; height: 15px; }
.os-tool:hover { background: var(--panel-soft); color: var(--ink); border-color: var(--line); }
.os-tool-strong { color: var(--accent); }
.os-tool:disabled { opacity: .38; cursor: not-allowed; }
.os-tool:disabled:hover { background: none; border-color: transparent; color: var(--ink-2); }
.os-tool-strong:disabled:hover { color: var(--accent); }

.os-tool-cost {
    display: inline-flex;
    align-items: center;
    padding: 1px 5px;
    margin-left: 2px;
    border-radius: 999px;
    font-family: var(--font-mono);
    font-size: 9px;
    line-height: 1.5;
    letter-spacing: 0;
    color: var(--gold);
    background: color-mix(in srgb, var(--gold) 12%, transparent);
    border: 1px solid color-mix(in srgb, var(--gold) 28%, transparent);
}
.os-tool.is-used .os-tool-cost {
    color: var(--ink-3);
    background: var(--panel-tint);
    border-color: var(--line);
}
.os-tool.is-pulse { animation: osToolPulse 1.15s ease-in-out 3; }
@keyframes osToolPulse {
    0%, 100% { box-shadow: 0 0 0 0 transparent; background: transparent; }
    50% { box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 18%, transparent); background: var(--accent-soft); }
}

/* 新手引导条（非弹窗，不打断操作） */
.os-coach {
    position: relative;
    z-index: 3;
    display: flex;
    align-items: flex-start;
    gap: 9px;
    margin: 0 2px 9px;
    padding: 9px 34px 9px 10px;
    border-radius: 11px;
    background: color-mix(in srgb, var(--jade-soft) 62%, transparent);
    border: 1px solid color-mix(in srgb, var(--jade) 20%, transparent);
    font-size: 12px;
    line-height: 1.65;
    color: var(--ink-2);
    animation: osFade .3s ease both;
}
.os-coach[hidden] { display: none; }
.os-coach p { margin: 0; }
.os-coach-mark {
    flex: none;
    width: 17px;
    height: 17px;
    margin-top: 1px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    font-family: var(--font-serif);
    font-size: 11px;
    font-style: italic;
    color: var(--jade);
    background: color-mix(in srgb, var(--jade) 12%, transparent);
    border: 1px solid color-mix(in srgb, var(--jade) 30%, transparent);
}
.os-coach-close {
    position: absolute;
    right: 5px;
    top: 5px;
    width: 22px;
    height: 22px;
    display: grid;
    place-items: center;
    border-radius: 6px;
    font-size: 15px;
    line-height: 1;
    color: var(--ink-3);
    transition: background-color .16s ease, color .16s ease;
}
.os-coach-close:hover { background: color-mix(in srgb, var(--jade) 12%, transparent); color: var(--ink); }

.os-tip {
    font-size: 11.5px;
    line-height: 1.55;
    color: var(--ink-3);
    max-width: 46%;
    text-align: right;
}

/* ==========================================================================
   右侧信息卡
   ========================================================================== */

.os-rail {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
    margin-top: 20px;
}

.os-card {
    padding: 16px 18px 17px;
    border-radius: var(--radius);
    background: color-mix(in srgb, var(--panel) 86%, transparent);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(4px);
}

.os-card-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    margin-bottom: 12px;
}
.os-card-head h2 {
    font-size: 13px;
    font-weight: 700;
    letter-spacing: .1em;
    color: var(--ink-3);
    font-family: var(--font-sans);
    text-transform: uppercase;
}

.os-stars { display: inline-flex; gap: 2px; font-size: 13px; color: var(--line-strong); letter-spacing: .06em; }
.os-stars .is-on { color: var(--gold); }
html[data-theme="dark"] .os-stars .is-on { color: var(--gold); }

.os-facts { display: grid; grid-template-columns: 1fr 1fr; gap: 12px 16px; }
.os-facts > div { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.os-facts dt { font-size: 11px; color: var(--ink-3); letter-spacing: .04em; }
.os-facts dd {
    font-size: 14px;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    font-variant-numeric: tabular-nums;
}

.os-card-note {
    margin-top: 12px;
    padding-top: 10px;
    border-top: 1px dashed var(--line);
    font-size: 11.5px;
    line-height: 1.6;
    color: var(--ink-3);
}

.os-tier-list { display: grid; gap: 11px; }
.os-tier-row {
    display: grid;
    gap: 5px;
    width: 100%;
    padding: 8px 10px;
    margin: 0 -10px;
    border: 1px solid transparent;
    border-radius: 10px;
    text-align: left;
    font: inherit;
    color: inherit;
    background: transparent;
    cursor: pointer;
    transition: background-color .16s ease, border-color .16s ease;
}
.os-tier-row:hover { background: var(--panel-soft); border-color: var(--line); }
.os-tier-row:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
.os-tier-row.is-active { background: color-mix(in srgb, var(--accent) 7%, var(--panel)); border-color: color-mix(in srgb, var(--accent) 30%, var(--line)); }
.os-tier-row-top { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; font-size: 12px; }
.os-tier-row-top b { font-weight: 600; }
.os-tier-row-top span { color: var(--ink-3); font-size: 11px; font-variant-numeric: tabular-nums; }
.os-tier-track {
    height: 6px;
    border-radius: 999px;
    background: var(--panel-tint);
    overflow: hidden;
    box-shadow: inset 0 1px 1px rgba(0, 0, 0, .04);
}
.os-tier-fill {
    height: 100%;
    width: 0;
    border-radius: 999px;
    background: linear-gradient(90deg, var(--jade), color-mix(in srgb, var(--jade) 55%, var(--accent)));
    transition: width .45s cubic-bezier(.2, .7, .3, 1);
}
.os-tier-row.is-locked .os-tier-fill { background: var(--line-strong); }
.os-tier-row.is-locked .os-tier-row-top b { color: var(--ink-3); }

.os-mini-rank { display: grid; gap: 7px; min-height: 96px; }
.os-mini-rank li {
    display: grid;
    grid-template-columns: 20px minmax(0, 1fr) auto;
    align-items: center;
    gap: 8px;
    font-size: 12.5px;
    line-height: 1.5;
}
.os-mini-rank li.os-rank-empty { display: block; }
.os-mini-rank .rk {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--ink-3);
    text-align: center;
}
.os-mini-rank li:nth-child(1) .rk { color: var(--gold); font-weight: 700; }
.os-mini-rank .nm { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.os-mini-rank .sc { font-family: var(--font-mono); font-size: 12px; color: var(--accent); font-variant-numeric: tabular-nums; }
.os-mini-rank .sc small { color: var(--ink-3); font-size: 10px; margin-left: 1px; }
.os-rank-empty { font-size: 12px; color: var(--ink-3); display: block; }

/* ==========================================================================
   正文
   ========================================================================== */

.os-content {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: clamp(28px, 4vw, 56px);
    padding: clamp(44px, 6vw, 76px) 0 56px;
    border-top: 1px solid var(--line);
    margin-top: clamp(36px, 5vw, 60px);
}

.os-content-main { max-width: 760px; }

.os-content h2 {
    position: relative;
    font-family: var(--font-serif);
    font-size: clamp(20px, 2vw, 25px);
    line-height: 1.4;
    letter-spacing: .02em;
    font-weight: 700;
    margin: 42px 0 14px;
    padding-left: 15px;
}
.os-content h2:first-child { margin-top: 0; }
.os-content h2::before {
    content: "";
    position: absolute;
    left: 0;
    top: .34em;
    width: 4px;
    height: 1.02em;
    border-radius: 3px;
    background: linear-gradient(180deg, var(--accent), color-mix(in srgb, var(--accent) 40%, var(--jade)));
}

.os-content p {
    font-size: 15px;
    line-height: 1.95;
    color: var(--ink-2);
    margin-bottom: 12px;
}
.os-content strong, .os-content b {
    color: var(--ink);
    font-weight: 700;
    background-image: linear-gradient(transparent 66%, color-mix(in srgb, var(--gold) 32%, transparent) 0);
    background-repeat: no-repeat;
    background-size: 100% 100%;
    padding: 0 .08em;
}

.os-steps { display: grid; gap: 10px; margin: 18px 0 6px; counter-reset: step; }
.os-steps li {
    position: relative;
    padding: 14px 16px 14px 46px;
    border-radius: var(--radius-sm);
    background: color-mix(in srgb, var(--panel) 70%, transparent);
    border: 1px solid var(--line);
    counter-increment: step;
}
.os-steps li::before {
    content: counter(step);
    position: absolute;
    left: 14px;
    top: 14px;
    width: 22px;
    height: 22px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--accent-ink);
    background: var(--accent-soft);
    border: 1px solid color-mix(in srgb, var(--accent) 22%, transparent);
}
/* 仅步骤标题独占一行；步骤正文里的 <b> 保持行内高亮，避免把句子拆断 */
.os-steps > li > b { display: block; font-size: 13.5px; margin-bottom: 1px; background: none; }
.os-steps p b { background-image: linear-gradient(transparent 68%, color-mix(in srgb, var(--gold) 34%, transparent) 0); }
.os-steps p { font-size: 13px; line-height: 1.8; margin: 0; }

.os-tier-cards { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; margin: 18px 0 8px; }
.os-tier-cards article {
    padding: 14px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--line);
    background: color-mix(in srgb, var(--panel) 72%, transparent);
}
.os-tier-cards b {
    display: block;
    font-family: var(--font-mono);
    font-size: 20px;
    font-weight: 600;
    margin: 9px 0 4px;
    background: none;
    letter-spacing: -.02em;
}
.os-tier-cards p { font-size: 12px; line-height: 1.7; margin: 0; }

.os-tier-chip {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 999px;
    font-size: 10.5px;
    font-weight: 700;
    letter-spacing: .05em;
    color: var(--accent-ink);
    background: var(--accent-soft);
}
.os-tier-chip[data-tier="medium"] { color: #7a5312; background: var(--gold-soft); }
html[data-theme="dark"] .os-tier-chip[data-tier="medium"] { color: #ecc887; }
.os-tier-chip[data-tier="hard"] { color: #245c4e; background: var(--jade-soft); }
html[data-theme="dark"] .os-tier-chip[data-tier="hard"] { color: #8fe2c4; }

.os-quote-list {
    display: grid;
    gap: 8px;
    margin: 12px 0 16px;
}
.os-quote-list li {
    padding: 10px 14px;
    border-left: 2px solid var(--line-strong);
    background: color-mix(in srgb, var(--panel) 55%, transparent);
    border-radius: 0 10px 10px 0;
    font-size: 13.5px;
    line-height: 1.8;
    color: var(--ink-2);
}

.os-faq { border-top: 1px solid var(--line); margin-top: 6px; }
.os-faq details { border-bottom: 1px solid var(--line); }
.os-faq summary {
    position: relative;
    padding: 14px 34px 14px 2px;
    font-size: 14px;
    font-weight: 600;
    color: var(--ink);
    cursor: pointer;
    list-style: none;
}
.os-faq summary::-webkit-details-marker { display: none; }
.os-faq summary::after {
    content: "+";
    position: absolute;
    right: 6px;
    top: 50%;
    transform: translateY(-50%);
    font-family: var(--font-mono);
    font-size: 18px;
    font-weight: 400;
    color: var(--ink-3);
    transition: transform .2s ease, color .2s ease;
}
.os-faq details[open] summary::after { transform: translateY(-50%) rotate(45deg); color: var(--accent); }
.os-faq p { font-size: 13.5px; line-height: 1.9; padding: 0 2px 14px; margin: 0; }

.os-content-side h2 {
    font-family: var(--font-sans);
    font-size: 12px;
    letter-spacing: .14em;
    color: var(--ink-3);
    text-transform: uppercase;
    margin: 0 0 12px;
    padding-left: 0;
}
.os-content-side h2::before { display: none; }

.os-rel { display: grid; gap: 2px; }
.os-rel a {
    display: flex;
    flex-direction: column;
    gap: 1px;
    padding: 9px 10px;
    border-radius: 10px;
    border: 1px solid transparent;
    transition: background-color .16s ease, border-color .16s ease;
}
.os-rel a:hover { background: var(--panel); border-color: var(--line); }
.os-rel b { font-size: 13px; font-weight: 600; }
.os-rel small { font-size: 11.5px; color: var(--ink-3); }

.os-side-note {
    margin-top: 18px;
    padding: 14px;
    border-radius: var(--radius-sm);
    background: color-mix(in srgb, var(--jade-soft) 55%, transparent);
    border: 1px solid color-mix(in srgb, var(--jade) 18%, transparent);
}
.os-side-note b { font-size: 11.5px; letter-spacing: .08em; color: var(--jade); text-transform: uppercase; }
.os-side-note p { font-size: 12px; line-height: 1.75; color: var(--ink-2); margin-top: 4px; }

/* ==========================================================================
   弹窗
   ========================================================================== */

.os-modal { position: fixed; inset: 0; z-index: 300; display: grid; place-items: center; padding: 20px; }
.os-modal[hidden] { display: none; }

.os-modal-mask {
    position: absolute;
    inset: 0;
    background: color-mix(in srgb, #0a1012 55%, transparent);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    animation: osFade .22s ease both;
}

.os-dialog {
    position: relative;
    width: min(540px, 100%);
    max-height: min(86vh, 760px);
    display: flex;
    flex-direction: column;
    padding: 22px;
    border-radius: 22px;
    background: var(--panel);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-lg);
    animation: osPop .26s cubic-bezier(.2, .8, .25, 1) both;
}
.os-dialog-wide { width: min(940px, 100%); }
.os-dialog-sm { width: min(420px, 100%); }

@keyframes osFade { from { opacity: 0; } to { opacity: 1; } }
@keyframes osPop {
    from { opacity: 0; transform: translateY(12px) scale(.985); }
    to { opacity: 1; transform: none; }
}

.os-dialog-head {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 16px;
}
.os-dialog-head h2 {
    font-family: var(--font-serif);
    font-size: 22px;
    letter-spacing: .04em;
    line-height: 1.3;
}
.os-dialog-head p { font-size: 12px; color: var(--ink-3); margin-top: 3px; }

.os-close {
    flex: none;
    width: 34px;
    height: 34px;
    display: grid;
    place-items: center;
    border-radius: 9px;
    color: var(--ink-3);
    border: 1px solid transparent;
    transition: background-color .16s ease, color .16s ease;
}
.os-close:hover { background: var(--panel-soft); color: var(--ink); border-color: var(--line); }
.os-close svg { width: 17px; height: 17px; }
.os-close-abs { position: absolute; right: 14px; top: 14px; z-index: 3; }

.os-map-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
}
.os-map-top .os-tabs { align-self: auto; }

.os-tabs {
    display: inline-flex;
    gap: 2px;
    padding: 3px;
    border-radius: 11px;
    background: var(--panel-tint);
    border: 1px solid var(--line);
    align-self: flex-start;
}
.os-tab {
    padding: 6px 16px;
    border-radius: 8px;
    font-size: 12.5px;
    font-weight: 600;
    color: var(--ink-3);
    transition: background-color .16s ease, color .16s ease, box-shadow .16s ease;
}
.os-tab.is-on { background: var(--panel); color: var(--ink); box-shadow: 0 1px 2px rgba(0, 0, 0, .08); }
.os-tab:disabled { opacity: .5; cursor: not-allowed; }
.os-tabs-sm .os-tab { padding: 5px 12px; font-size: 12px; }

.os-tier-hint {
    margin: 10px 2px 12px;
    font-size: 12px;
    line-height: 1.6;
    color: var(--ink-3);
    min-height: 19px;
}
.os-tier-hint b { color: var(--accent); font-weight: 600; background: none; }

.os-level-grid {
    flex: 1;
    min-height: 0;
    overflow-y: auto;
    display: grid;
    grid-template-columns: repeat(10, minmax(0, 1fr));
    gap: 7px;
    padding: 4px 6px 4px 2px;
    scrollbar-width: thin;
    scrollbar-color: var(--line-strong) transparent;
}
.os-level-grid::-webkit-scrollbar { width: 6px; }
.os-level-grid::-webkit-scrollbar-thumb { background: var(--line-strong); border-radius: 3px; }

/* 选关：难度配色 / 分组标题 / 图例 */
.os-level-grid[data-tier="easy"] { --tier-c: var(--accent); }
.os-level-grid[data-tier="medium"] { --tier-c: var(--gold); }
.os-level-grid[data-tier="hard"] { --tier-c: var(--jade); }

.os-map-legend {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px 14px;
    margin: 0 2px 10px;
    font-size: 11px;
    color: var(--ink-3);
}
.os-lg-item { display: inline-flex; align-items: center; gap: 5px; }
.os-lg-stars { font-style: normal; font-size: 9px; letter-spacing: 1px; color: var(--gold); }
.os-lg-dash { width: 15px; height: 10px; border-radius: 3px; border: 1px dashed var(--line-strong); }
.os-lg-cur { width: 15px; height: 10px; border-radius: 3px; border: 1px solid var(--accent); box-shadow: inset 0 0 0 1px var(--accent); }
.os-lg-tip { margin-left: auto; }

.os-chapter {
    grid-column: 1 / -1;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 9px 2px 1px;
    font-size: 11px;
    color: var(--ink-3);
}
.os-chapter:first-child { padding-top: 0; }
.os-chapter-no {
    font-family: var(--font-mono);
    font-size: 10px;
    letter-spacing: .06em;
    padding: 1px 6px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: var(--panel-soft);
}
.os-chapter-name { font-weight: 600; letter-spacing: .06em; color: var(--ink-2); }
.os-chapter-stars { margin-left: auto; flex: none; white-space: nowrap; font-family: var(--font-mono); font-size: 10px; color: var(--gold); }

.os-tab-count {
    display: inline-block;
    margin-left: 5px;
    font-family: var(--font-mono);
    font-size: 9.5px;
    font-weight: 600;
    color: var(--ink-3);
}
.os-tab.is-on .os-tab-count { color: var(--tier-c, var(--accent)); }

.os-level-btn {
    position: relative;
    height: 46px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    border-radius: 9px;
    border: 1px solid var(--line);
    background: var(--panel-soft);
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 600;
    color: var(--ink-2);
    transition: transform .14s ease, border-color .14s ease, background-color .14s ease, color .14s ease;
}
.os-level-btn:hover { border-color: var(--tier-c, var(--accent)); color: var(--tier-c, var(--accent)); transform: translateY(-1px); }
.os-level-btn .st { font-size: 8px; letter-spacing: 1px; color: var(--line-strong); line-height: 1; }
.os-level-btn.is-cleared { background: color-mix(in srgb, var(--gold-soft) 55%, var(--panel)); border-color: color-mix(in srgb, var(--gold) 35%, var(--line)); color: var(--ink); }
.os-level-btn.is-perfect { background: linear-gradient(160deg, color-mix(in srgb, var(--gold-soft) 88%, var(--panel)), var(--panel)); }
.os-level-btn .st .on { color: var(--gold); }
.os-level-btn.is-current { border-color: var(--tier-c, var(--accent)); box-shadow: 0 0 0 1px var(--tier-c, var(--accent)) inset, 0 6px 14px -10px rgba(179, 69, 31, .8); }
.os-level-btn.is-next::after {
    content: "";
    position: absolute;
    inset: -3px;
    border-radius: 12px;
    border: 1px solid color-mix(in srgb, var(--tier-c, var(--accent)) 62%, transparent);
    animation: osNextPulse 1.9s ease-out infinite;
    pointer-events: none;
}
@keyframes osNextPulse {
    0% { opacity: .9; transform: scale(.96); }
    75%, 100% { opacity: 0; transform: scale(1.1); }
}
.os-level-btn.is-locked { color: var(--ink-3); background: transparent; border-style: dashed; opacity: .62; cursor: not-allowed; }
.os-level-btn.is-locked:hover { transform: none; border-color: var(--line); color: var(--ink-3); }
.os-level-btn.is-locked .st { display: none; }
.os-level-btn.is-locked .no { font-size: 10px; opacity: .62; }
.os-level-btn .lock { width: 11px; height: 11px; opacity: .6; }

.os-dialog-foot {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-top: 14px;
    padding-top: 12px;
    border-top: 1px solid var(--line);
    font-size: 11.5px;
    color: var(--ink-3);
    flex-wrap: wrap;
}
.os-dialog-foot b { color: var(--accent); font-weight: 600; font-family: var(--font-mono); }

/* 排行榜 */
.os-rank-top {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 12px;
}
.os-name-field {
    flex: 1;
    min-width: 150px;
    display: flex;
    align-items: center;
    gap: 7px;
    padding: 0 10px;
    height: 34px;
    border-radius: 9px;
    border: 1px solid var(--line);
    background: var(--panel-soft);
    font-size: 12px;
    color: var(--ink-3);
}
.os-name-field input {
    flex: 1;
    min-width: 0;
    border: 0;
    background: none;
    outline: none;
    font-size: 12.5px;
    color: var(--ink);
}
.os-name-field input::placeholder { color: var(--ink-3); }

.os-rank-list {
    flex: 1;
    min-height: 200px;
    max-height: 46vh;
    overflow-y: auto;
    margin: 0 -4px;
    padding: 0 4px;
    scrollbar-width: thin;
    scrollbar-color: var(--line-strong) transparent;
}
.os-rank-list::-webkit-scrollbar { width: 6px; }
.os-rank-list::-webkit-scrollbar-thumb { background: var(--line-strong); border-radius: 3px; }

.os-rank-row {
    display: grid;
    grid-template-columns: 34px minmax(0, 1fr) auto;
    align-items: center;
    gap: 10px;
    padding: 9px 10px;
    border-radius: 10px;
    border-bottom: 1px solid color-mix(in srgb, var(--line) 60%, transparent);
    font-size: 13px;
}
.os-rank-row:last-child { border-bottom: 0; }
.os-rank-row.is-me { background: color-mix(in srgb, var(--accent-soft) 55%, transparent); border-bottom-color: transparent; }
.os-rank-row .rk {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--ink-3);
    text-align: center;
}
.os-rank-row.top1 .rk { color: var(--gold); font-weight: 700; font-size: 14px; }
.os-rank-row.top2 .rk { color: var(--ink-2); font-weight: 700; font-size: 13px; }
.os-rank-row.top3 .rk { color: var(--accent); font-weight: 700; font-size: 13px; }
.os-rank-row .who { display: flex; flex-direction: column; min-width: 0; }
.os-rank-row .who b { font-weight: 600; font-size: 13px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.os-rank-row .who small { font-size: 10.5px; color: var(--ink-3); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.os-rank-row .sc {
    font-family: var(--font-mono);
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
}
.os-rank-row .sc small { font-size: 10px; color: var(--ink-3); margin-left: 1px; font-weight: 400; }

.os-rank-mine {
    margin-top: 10px;
    padding: 9px 12px;
    border-radius: 10px;
    background: var(--panel-soft);
    border: 1px dashed var(--line-strong);
    font-size: 12px;
    color: var(--ink-2);
    display: none;
}
.os-rank-mine.is-on { display: block; }
.os-rank-mine b { color: var(--accent); font-family: var(--font-mono); }

/* 结算 */
.os-dialog-win {
    width: min(480px, 100%);
    text-align: center;
    padding: 30px 26px 24px;
    overflow-x: hidden;
    overflow-y: auto;
}
.os-win-eyebrow {
    font-size: 11.5px;
    letter-spacing: .16em;
    color: var(--accent);
    text-transform: uppercase;
    font-weight: 600;
}
.os-win-record {
    display: inline-block;
    margin-left: 8px;
    padding: 2px 8px;
    border-radius: 999px;
    font-size: 10px;
    letter-spacing: .06em;
    font-weight: 600;
    color: var(--accent-ink);
    background: var(--accent-soft);
    border: 1px solid color-mix(in srgb, var(--accent) 26%, transparent);
    vertical-align: 1px;
}
.os-win-record[hidden] { display: none; }
.os-dialog-win h2 {
    font-family: var(--font-serif);
    font-size: 30px;
    letter-spacing: .12em;
    margin: 6px 0 2px;
}
.os-win-stars { display: flex; justify-content: center; gap: 6px; margin: 12px 0 4px; font-size: 34px; line-height: 1.2; }
.os-win-stars span { color: var(--line-strong); transform: scale(.86); display: inline-block; }
.os-win-stars span.is-on { color: var(--gold); animation: osStarPop .5s cubic-bezier(.2, .9, .3, 1.2) both; text-shadow: 0 3px 14px color-mix(in srgb, var(--gold) 45%, transparent); }
.os-win-stars span.is-on:nth-child(2) { animation-delay: .1s; }
.os-win-stars span.is-on:nth-child(3) { animation-delay: .2s; }
@keyframes osStarPop {
    0% { transform: scale(.3) rotate(-25deg); opacity: 0; }
    70% { transform: scale(1.16) rotate(4deg); opacity: 1; }
    100% { transform: scale(1) rotate(0); }
}
.os-win-note { font-size: 12.5px; color: var(--ink-2); margin-top: 4px; }

.os-win-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    margin: 18px 0 20px;
    border-radius: 12px;
    background: var(--line);
    overflow: hidden;
    border: 1px solid var(--line);
}
.os-win-stats > div { padding: 11px 6px; background: var(--panel-soft); display: flex; flex-direction: column; gap: 1px; }
.os-win-stats b { font-family: var(--font-mono); font-size: 16px; font-weight: 600; font-variant-numeric: tabular-nums; }
.os-win-stats small { font-size: 10.5px; color: var(--ink-3); }

.os-win-actions { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; }
.os-win-actions .os-btn { flex: 1 1 auto; min-width: 100px; }
.os-win-share-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 12px;
    font-size: 11px;
    color: var(--jade);
    min-height: 17px;
}
.os-win-share {
    font-size: 12px;
    font-weight: 600;
    color: var(--accent);
    padding: 2px 1px;
    border-bottom: 1px dashed color-mix(in srgb, var(--accent) 45%, transparent);
    transition: opacity .16s ease;
}
.os-win-share:hover { opacity: .78; }
.os-win-sync { margin-top: 8px; font-size: 11px; color: var(--ink-3); min-height: 16px; }

.os-win-confetti { position: absolute; inset: 0; overflow: hidden; pointer-events: none; }
.os-win-confetti span {
    position: absolute;
    top: -12px;
    left: var(--x, 50%);
    width: 6px;
    height: 10px;
    border-radius: 1px;
    background: var(--c, var(--accent));
    opacity: 0;
    animation: osConfetti var(--d, 1.8s) ease-in var(--delay, 0s) forwards;
}
@keyframes osConfetti {
    0% { opacity: 1; transform: translate3d(0, 0, 0) rotate(0); }
    100% { opacity: 0; transform: translate3d(var(--dx, 0), 430px, 0) rotate(var(--rot, 420deg)); }
}

.os-confirm-actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 18px; }

/* 怎么玩 */
.os-dialog-how { width: min(640px, 100%); }

.os-how-steps { display: grid; gap: 10px; margin: 2px 0 14px; }
.os-how-steps li {
    display: grid;
    grid-template-columns: 24px minmax(0, 1fr) 96px;
    align-items: center;
    gap: 12px;
    padding: 12px 14px;
    border-radius: 12px;
    border: 1px solid var(--line);
    background: var(--panel-soft);
}
.os-how-no {
    width: 24px;
    height: 24px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    font-family: var(--font-mono);
    font-size: 11.5px;
    font-weight: 700;
    color: var(--accent-ink);
    background: var(--accent-soft);
    border: 1px solid color-mix(in srgb, var(--accent) 24%, transparent);
}
.os-how-body b { display: block; font-size: 14px; font-weight: 700; }
.os-how-body p { font-size: 12.5px; line-height: 1.7; color: var(--ink-2); margin-top: 2px; }

.os-how-demo { width: 96px; height: 62px; }
.os-how-demo .d { stroke: var(--edge-rest); stroke-width: 2.4; stroke-dasharray: 4 7; stroke-linecap: round; }
.os-how-demo .used { stroke: var(--jade); stroke-width: 4; stroke-linecap: round; }
.os-how-demo circle { fill: var(--panel); stroke: var(--line-strong); stroke-width: 2; }
.os-how-demo .odd { fill: var(--accent-soft); stroke: var(--accent); }
.os-how-demo .done { fill: var(--node-done); stroke: var(--node-done); }
.os-how-demo .cur { fill: var(--accent); stroke: var(--accent); }
.os-how-demo-bulb { stroke: var(--gold); stroke-width: 2; }

.os-how-tips {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 16px;
    padding: 10px 12px;
    border-radius: 10px;
    border: 1px dashed var(--line-strong);
    background: color-mix(in srgb, var(--panel-soft) 70%, transparent);
    font-size: 11.5px;
    color: var(--ink-3);
}
.os-how-tips b { color: var(--ink-2); margin-right: 4px; }

.os-how-foot {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 14px;
    padding-top: 12px;
    border-top: 1px solid var(--line);
}
.os-how-mute { display: inline-flex; align-items: center; gap: 7px; font-size: 12px; color: var(--ink-3); cursor: pointer; }
.os-how-mute input { width: 15px; height: 15px; accent-color: var(--accent); }
.os-how-actions { display: flex; gap: 8px; margin-left: auto; }

/* ==========================================================================
   响应式
   ========================================================================== */

@media (max-width: 1080px) {
    .os-hero { grid-template-columns: minmax(0, .86fr) minmax(0, 1.14fr); gap: 28px; }
    .os-content { grid-template-columns: minmax(0, 1fr) 260px; gap: 32px; }
    .os-hero h1 span { letter-spacing: .34em; }
}

@media (max-width: 900px) {
    .os-hero { grid-template-columns: minmax(0, 1fr); gap: 22px; padding-top: 20px; }
    .os-hero-copy { order: 1; }
    .os-board-card { order: 2; }
    .os-sub { max-width: none; }
    .os-hero-total { display: none; }
    .os-rail { grid-template-columns: 1fr 1fr; }
    .os-rail > .os-card:nth-child(3) { grid-column: 1 / -1; }
    .os-content { grid-template-columns: minmax(0, 1fr); }
    .os-content-side { margin-top: 8px; }
    .os-content-side h2 { margin-top: 0; }
    .os-level-grid { grid-template-columns: repeat(8, minmax(0, 1fr)); }
    .os-tip { max-width: 100%; text-align: left; }
    .os-board-foot { gap: 6px; }
    .os-board-stage { max-height: 56vh; }
}

@media (max-width: 640px) {
    .os-tool.os-tool-bulb { padding: 7px 9px; font-size: 11.5px; }
    .os-how-steps li { grid-template-columns: 24px minmax(0, 1fr); }
    .os-how-demo { display: none; }
    .os-how-foot { align-items: stretch; }
    .os-how-actions { flex: 1 1 100%; }
    .os-how-actions .os-btn { flex: 1 1 auto; }
    .os-lg-tip { display: none; }

    .os-hide-sm { display: none !important; }

    .os-main { padding: 0 14px; }
    .os-hero { padding-top: 14px; gap: 18px; }
    .os-eyebrow { font-size: 10.5px; letter-spacing: .12em; }
    .os-hero h1 { font-size: clamp(34px, 10vw, 44px); margin-top: 10px; }
    .os-hero h1 span { margin-top: 8px; font-size: 12.5px; letter-spacing: .26em; }
    .os-sub { font-size: 13.5px; line-height: 1.8; margin-top: 12px; }
    .os-hero-cta { margin-top: 16px; gap: 8px; }
    .os-hero-cta .os-btn { flex: 1 1 auto; }
    .os-btn-lg { padding: 11px 16px; font-size: 14px; }
    .os-hero-points { margin-top: 12px; font-size: 11.5px; gap: 4px 14px; }

    .os-board-card { padding: 11px; border-radius: 20px; }
    .os-board-card::before { inset: 5px; }
    .os-coach { font-size: 11.5px; line-height: 1.6; padding: 8px 30px 8px 9px; margin-bottom: 8px; }
    .os-coach-mark { width: 15px; height: 15px; font-size: 10px; }
    .os-tool-cost { font-size: 8px; padding: 1px 4px; }
    .os-map-top .os-btn { flex: 1 1 100%; }
    .os-win-share-row { margin-top: 10px; }
    .os-board-head { padding: 4px 4px 9px; gap: 8px; }
    .os-level-name { font-size: 15px; }
    .os-level-rule { display: none; }
    .os-meter b { font-size: 13.5px; }
    .os-meters { gap: 10px; }
    .os-board-stage { max-height: 52vh; aspect-ratio: 1 / 1.02; border-radius: 14px; }
    .os-tools { width: 100%; justify-content: space-between; }
    .os-tool { padding: 7px 9px; font-size: 12px; }
    .os-tip { font-size: 11px; }

    .os-rail { grid-template-columns: 1fr; gap: 10px; margin-top: 14px; }
    .os-rail > .os-card:nth-child(3) { grid-column: auto; }
    .os-card { padding: 14px 15px; }

    .os-content { padding: 34px 0 40px; margin-top: 30px; gap: 26px; }
    .os-content h2 { font-size: 19px; margin: 32px 0 10px; }
    .os-content p { font-size: 14px; line-height: 1.9; }
    .os-tier-cards { grid-template-columns: 1fr; }
    .os-steps li { padding: 13px 13px 13px 42px; }

    .os-modal { padding: 10px; }
    .os-dialog { padding: 18px 16px; border-radius: 18px; max-height: 88vh; }
    .os-dialog-head h2 { font-size: 19px; }
    .os-level-grid { grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 6px; }
    .os-level-btn { min-height: 44px; font-size: 12.5px; }
    .os-dialog-foot { font-size: 11px; }
    .os-rank-top { gap: 8px; }
    .os-rank-top .os-name-field { flex: 1 1 100%; order: 2; }
    .os-rank-top .os-btn { order: 3; flex: 1 1 auto; }
    .os-rank-top .os-tabs { order: 1; }
    .os-dialog-win { padding: 26px 18px 20px; }
    .os-dialog-win h2 { font-size: 26px; }
    .os-win-actions .os-btn { flex: 1 1 100%; }
}

@media (max-width: 380px) {
    .os-hero-points li:nth-child(3) { display: none; }
    .os-tools { flex-wrap: wrap; }
}

/* 无障碍与省电偏好 */
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after {
        animation-duration: .001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: .001ms !important;
    }
    .os-win-confetti { display: none; }
}

/* 触屏设备去掉 hover 残留 */
@media (hover: none) {
    .os-level-btn:hover { transform: none; }
}