/* ==========================================================================
   desk3 · 工程台设计系统
   定位：面向制造/工程计算的工具页通用底座。纸感浅色 + 深墨深色，
   字号层级克制，数字等宽，边框用发丝线而非阴影。
   仅新增页面引用，不覆盖 desk / desk2 既有样式。
   ========================================================================== */

/* ---------- 1. 设计令牌 ---------- */
:root {
    --d3-paper: #f6f4ef;
    --d3-paper-2: #efece4;
    --d3-card: #fffdf8;
    --d3-card-2: #fbf8f1;
    --d3-ink: #15181d;
    --d3-ink-2: #3f4750;
    --d3-ink-3: #6d7683;
    --d3-line: #e3ded3;
    --d3-line-2: #cfc7b7;
    --d3-accent: #9a5b21;
    --d3-accent-rgb: 154, 91, 33;
    --d3-accent-ink: #ffffff;
    --d3-ok: #1d6b4f;
    --d3-warn: #a8541a;
    --d3-bad: #b02a24;
    --d3-radius: 10px;
    --d3-radius-sm: 7px;

    --d3-fs-display: clamp(29px, 3.6vw, 42px);
    --d3-fs-h2: 21px;
    --d3-fs-h3: 15.5px;
    --d3-fs-body: 15.5px;
    --d3-fs-small: 13.5px;
    --d3-fs-label: 12.5px;

    --d3-sans: "Inter", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, sans-serif;
    --d3-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Mono", Consolas, monospace;
    --d3-wrap: 1180px;
}

:root[data-theme="dark"] {
    --d3-paper: #0c0e12;
    --d3-paper-2: #101319;
    --d3-card: #141820;
    --d3-card-2: #171c25;
    --d3-ink: #eef1f6;
    --d3-ink-2: #b7c0cc;
    --d3-ink-3: #8a94a2;
    --d3-line: #232a35;
    --d3-line-2: #333c4a;
    --d3-accent-ink: #0c0e12;
    --d3-ok: #4fbb92;
    --d3-warn: #e2a165;
    --d3-bad: #f0857e;
}

/* ---------- 2. 基础重置 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
    margin: 0;
    font-family: var(--d3-sans);
    font-size: var(--d3-fs-body);
    line-height: 1.78;
    color: var(--d3-ink);
    background-color: var(--d3-paper);
    background-image:
        radial-gradient(1100px 520px at 12% -8%, rgba(var(--d3-accent-rgb), .10), transparent 68%),
        linear-gradient(to bottom, rgba(0, 0, 0, .022) 1px, transparent 1px);
    background-size: auto, 100% 32px;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 { margin: 0; line-height: 1.28; font-weight: 700; letter-spacing: -.015em; }
p { margin: 0; }
a { color: var(--d3-accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
b, strong { font-weight: 650; }
img { max-width: 100%; height: auto; }

::selection { background: rgba(var(--d3-accent-rgb), .22); }

:focus-visible {
    outline: 2px solid rgba(var(--d3-accent-rgb), .75);
    outline-offset: 2px;
    border-radius: 3px;
}

.d3-skip {
    position: absolute; left: -9999px;
    background: var(--d3-accent); color: var(--d3-accent-ink);
    padding: 10px 16px; border-radius: 0 0 8px 0; z-index: 99;
}
.d3-skip:focus { left: 0; top: 0; }

.d3-wrap {
    width: 100%;
    max-width: var(--d3-wrap);
    margin: 0 auto;
    padding: 0 22px;
}

/* ---------- 3. 顶栏 ---------- */
.d3-top {
    position: sticky; top: 0; z-index: 40;
    background: color-mix(in srgb, var(--d3-paper) 86%, transparent);
    border-bottom: 1px solid var(--d3-line);
    backdrop-filter: saturate(160%) blur(12px);
    -webkit-backdrop-filter: saturate(160%) blur(12px);
}

@supports not (background: color-mix(in srgb, red 50%, transparent)) {
    .d3-top { background: var(--d3-paper); }
}

.d3-top-in {
    display: flex; align-items: center; gap: 18px;
    height: 60px;
}

.d3-brand {
    display: inline-flex; align-items: center; gap: 9px;
    color: var(--d3-ink); font-weight: 700; font-size: 15px;
    letter-spacing: -.01em; text-decoration: none;
}
.d3-brand:hover { text-decoration: none; }

.d3-brand-mark {
    width: 24px; height: 24px; flex: none;
    border: 1.5px solid var(--d3-accent);
    border-radius: 6px;
    display: grid; place-items: center;
    background: rgba(var(--d3-accent-rgb), .09);
}
.d3-brand-mark::after {
    content: "";
    width: 8px; height: 8px;
    border: 1.5px solid var(--d3-accent);
    border-radius: 2px;
    opacity: .7;
}

.d3-nav {
    margin-left: auto;
    display: flex; align-items: center; gap: 4px;
}

.d3-nav > a {
    padding: 7px 11px; border-radius: 7px;
    font-size: var(--d3-fs-small); color: var(--d3-ink-2);
}
.d3-nav > a:hover { background: var(--d3-paper-2); color: var(--d3-ink); text-decoration: none; }

.d3-seg {
    display: inline-flex; padding: 2px; gap: 2px;
    border: 1px solid var(--d3-line-2);
    border-radius: 8px;
    background: var(--d3-card);
}

.d3-seg button {
    appearance: none; border: 0; background: transparent; cursor: pointer;
    font-family: inherit; font-size: 12px; line-height: 1;
    color: var(--d3-ink-3);
    padding: 7px 9px; border-radius: 6px;
    transition: background .16s ease, color .16s ease;
}
.d3-seg button:hover { color: var(--d3-ink); }
.d3-seg button[aria-pressed="true"] {
    background: rgba(var(--d3-accent-rgb), .13);
    color: var(--d3-accent);
    font-weight: 650;
}

/* ---------- 4. 首屏 ---------- */
.d3-hero { padding: 34px 0 26px; }

.d3-crumb {
    display: flex; align-items: center; gap: 7px;
    font-size: 12.5px; color: var(--d3-ink-3);
    margin-bottom: 20px;
}
.d3-crumb a { color: var(--d3-ink-3); }
.d3-crumb a:hover { color: var(--d3-accent); text-decoration: none; }
.d3-crumb i { font-style: normal; opacity: .5; }

.d3-eyebrow {
    display: inline-flex; align-items: center; gap: 8px;
    font-family: var(--d3-mono);
    font-size: 11px; letter-spacing: .16em; text-transform: uppercase;
    color: var(--d3-accent);
    margin-bottom: 12px;
}
.d3-eyebrow::before {
    content: ""; width: 22px; height: 1px; background: var(--d3-accent);
    opacity: .6;
}

.d3-h1 {
    font-size: var(--d3-fs-display);
    line-height: 1.18;
    letter-spacing: -.03em;
    max-width: 19em;
}
.d3-h1 em {
    font-style: normal;
    color: var(--d3-accent);
    box-shadow: inset 0 -.32em 0 rgba(var(--d3-accent-rgb), .15);
}

.d3-sub {
    margin-top: 14px;
    max-width: 40em;
    font-size: 16px;
    line-height: 1.85;
    color: var(--d3-ink-2);
}
.d3-sub b { color: var(--d3-ink); font-weight: 650; }

/* 首屏下方的工具操作区：桌面双栏 */
.d3-desk {
    display: grid;
    grid-template-columns: minmax(0, 1.16fr) minmax(0, .84fr);
    gap: 20px;
    align-items: start;
    margin-top: 26px;
}

/* ---------- 5. 面板 ---------- */
.d3-panel {
    background: var(--d3-card);
    border: 1px solid var(--d3-line);
    border-radius: var(--d3-radius);
    overflow: hidden;
}

.d3-panel-head {
    display: flex; align-items: baseline; gap: 10px;
    padding: 14px 18px;
    border-bottom: 1px solid var(--d3-line);
    background: var(--d3-card-2);
}
.d3-panel-head h2 {
    font-size: var(--d3-fs-h3);
    letter-spacing: -.01em;
}
.d3-panel-head span {
    margin-left: auto;
    font-family: var(--d3-mono);
    font-size: 11.5px;
    color: var(--d3-ink-3);
    letter-spacing: .04em;
}

.d3-panel-body { padding: 18px; }

.d3-group + .d3-group {
    margin-top: 18px;
    padding-top: 18px;
    border-top: 1px dashed var(--d3-line);
}

.d3-group-title {
    display: flex; align-items: center; gap: 8px;
    font-family: var(--d3-mono);
    font-size: 11px; letter-spacing: .14em; text-transform: uppercase;
    color: var(--d3-ink-3);
    margin-bottom: 12px;
}
.d3-group-title::after {
    content: ""; flex: 1; height: 1px; background: var(--d3-line);
}

/* 字段网格 */
.d3-fields {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 13px 14px;
}
.d3-fields.cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.d3-field.span-2 { grid-column: span 2; }

.d3-field { min-width: 0; }

.d3-field > label,
.d3-label {
    display: block;
    font-size: var(--d3-fs-label);
    font-weight: 600;
    color: var(--d3-ink-2);
    letter-spacing: .01em;
    margin-bottom: 6px;
}

.d3-hint {
    font-size: 12px;
    line-height: 1.65;
    color: var(--d3-ink-3);
    margin-top: 5px;
}
.d3-hint code {
    font-family: var(--d3-mono);
    font-size: 11.5px;
    padding: 1px 4px;
    border-radius: 4px;
    background: var(--d3-paper-2);
    color: var(--d3-ink-2);
}

/* 输入控件 */
.d3-io {
    display: flex; align-items: stretch;
    background: var(--d3-paper);
    border: 1px solid var(--d3-line-2);
    border-radius: var(--d3-radius-sm);
    transition: border-color .15s ease, box-shadow .15s ease, background .15s ease;
}
.d3-io:focus-within {
    border-color: var(--d3-accent);
    box-shadow: 0 0 0 3px rgba(var(--d3-accent-rgb), .13);
    background: var(--d3-card);
}
.d3-io.is-bad { border-color: var(--d3-bad); }
.d3-io.is-bad:focus-within { box-shadow: 0 0 0 3px rgba(176, 42, 36, .14); }

.d3-io input,
.d3-io select {
    flex: 1 1 auto; min-width: 0;
    appearance: none;
    border: 0; background: transparent;
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    color: var(--d3-ink);
    padding: 10px 12px;
    border-radius: var(--d3-radius-sm);
    outline: none;
}
.d3-io input::-webkit-outer-spin-button,
.d3-io input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.d3-io input[type="number"] { -moz-appearance: textfield; }

.d3-io select {
    cursor: pointer;
    font-weight: 600;
    background-image: none;
}

.d3-io .d3-unit {
    flex: none;
    display: grid; place-items: center;
    padding: 0 11px;
    font-family: var(--d3-mono);
    font-size: 11.5px;
    color: var(--d3-ink-3);
    border-left: 1px solid var(--d3-line);
    background: var(--d3-paper-2);
    border-radius: 0 var(--d3-radius-sm) var(--d3-radius-sm) 0;
    white-space: nowrap;
}

.d3-io.no-unit input { border-radius: var(--d3-radius-sm); }

/* 单选胶囊 */
.d3-chips { display: flex; flex-wrap: wrap; gap: 6px; }
.d3-chips input { position: absolute; opacity: 0; pointer-events: none; }
.d3-chips label {
    cursor: pointer;
    font-size: 12.5px;
    font-weight: 600;
    padding: 6px 11px;
    border: 1px solid var(--d3-line-2);
    border-radius: 999px;
    color: var(--d3-ink-2);
    background: var(--d3-paper);
    transition: all .14s ease;
    user-select: none;
}
.d3-chips label:hover { border-color: var(--d3-accent); color: var(--d3-accent); }
.d3-chips input:checked + label {
    background: var(--d3-accent);
    border-color: var(--d3-accent);
    color: var(--d3-accent-ink);
}
.d3-chips input:focus-visible + label { outline: 2px solid rgba(var(--d3-accent-rgb), .6); outline-offset: 2px; }

/* 开关 */
.d3-switch {
    display: flex; align-items: center; gap: 10px;
    cursor: pointer; user-select: none;
    font-size: var(--d3-fs-small); color: var(--d3-ink-2);
}
.d3-switch input { position: absolute; opacity: 0; pointer-events: none; }
.d3-switch .d3-track {
    position: relative; flex: none;
    width: 36px; height: 20px;
    border-radius: 999px;
    background: var(--d3-line-2);
    transition: background .16s ease;
}
.d3-switch .d3-track::after {
    content: ""; position: absolute; top: 2px; left: 2px;
    width: 16px; height: 16px; border-radius: 50%;
    background: var(--d3-card);
    box-shadow: 0 1px 2px rgba(0, 0, 0, .25);
    transition: transform .16s ease;
}
.d3-switch input:checked + .d3-track { background: var(--d3-accent); }
.d3-switch input:checked + .d3-track::after { transform: translateX(16px); }
.d3-switch input:focus-visible + .d3-track { outline: 2px solid rgba(var(--d3-accent-rgb), .6); outline-offset: 2px; }

/* ---------- 6. 结果 ---------- */
.d3-result {
    position: relative;
    background: var(--d3-card);
    border: 1px solid var(--d3-line);
    border-radius: var(--d3-radius);
    padding: 18px;
}

.d3-result-lead {
    display: flex; align-items: baseline; justify-content: space-between; gap: 12px;
    padding-bottom: 14px;
    border-bottom: 1px solid var(--d3-line);
}
.d3-result-lead .d3-rl-label {
    font-size: 12.5px; font-weight: 600; color: var(--d3-ink-3);
    letter-spacing: .02em;
}
.d3-big {
    font-family: var(--d3-mono);
    font-variant-numeric: tabular-nums;
    font-size: clamp(30px, 4.4vw, 40px);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -.03em;
    color: var(--d3-ink);
    display: inline-flex; align-items: baseline; gap: 6px;
}
.d3-big small {
    font-family: var(--d3-sans);
    font-size: 13px; font-weight: 600;
    color: var(--d3-ink-3);
    letter-spacing: 0;
}

.d3-kv {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1px;
    background: var(--d3-line);
    border: 1px solid var(--d3-line);
    border-radius: var(--d3-radius-sm);
    overflow: hidden;
    margin-top: 14px;
}
.d3-kv > div {
    background: var(--d3-card);
    padding: 9px 12px;
}
.d3-kv dt {
    font-size: 11.5px; color: var(--d3-ink-3);
    margin-bottom: 2px;
}
.d3-kv dd {
    margin: 0;
    font-family: var(--d3-mono);
    font-variant-numeric: tabular-nums;
    font-size: 14px; font-weight: 650;
    color: var(--d3-ink);
}

/* 构成条 */
.d3-stack {
    display: flex;
    height: 12px;
    border-radius: 999px;
    overflow: hidden;
    background: var(--d3-paper-2);
    border: 1px solid var(--d3-line);
    margin-top: 4px;
}
.d3-stack i {
    display: block; height: 100%;
    transition: width .28s cubic-bezier(.4, 0, .2, 1);
}

.d3-legend {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 4px 14px;
    margin-top: 10px;
    font-size: 12.5px;
}
.d3-legend div {
    display: flex; align-items: center; gap: 7px;
    color: var(--d3-ink-2);
    min-width: 0;
}
.d3-legend i {
    flex: none; width: 9px; height: 9px; border-radius: 2px;
}
.d3-legend b {
    margin-left: auto;
    font-family: var(--d3-mono);
    font-variant-numeric: tabular-nums;
    color: var(--d3-ink);
    font-weight: 600;
    white-space: nowrap;
}

/* ---------- 7. 表格 ---------- */
.d3-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    border: 1px solid var(--d3-line);
    border-radius: var(--d3-radius-sm);
}
.d3-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13.5px;
    min-width: 460px;
}
.d3-table th,
.d3-table td {
    padding: 9px 12px;
    text-align: right;
    border-bottom: 1px solid var(--d3-line);
    white-space: nowrap;
}
.d3-table th:first-child,
.d3-table td:first-child { text-align: left; }
.d3-table thead th {
    background: var(--d3-card-2);
    font-size: 11.5px;
    font-weight: 600;
    color: var(--d3-ink-3);
    letter-spacing: .03em;
}
.d3-table tbody tr:last-child td { border-bottom: 0; }
.d3-table td.num {
    font-family: var(--d3-mono);
    font-variant-numeric: tabular-nums;
}
.d3-table tbody tr:hover td { background: rgba(var(--d3-accent-rgb), .045); }
.d3-table tfoot td {
    font-weight: 700;
    background: var(--d3-card-2);
    border-top: 1px solid var(--d3-line-2);
}

/* ---------- 8. 提示 ---------- */
.d3-alert {
    display: flex; gap: 9px; align-items: flex-start;
    padding: 10px 12px;
    border-radius: var(--d3-radius-sm);
    font-size: 13px;
    line-height: 1.7;
    border: 1px solid var(--d3-line-2);
    background: var(--d3-paper-2);
    color: var(--d3-ink-2);
}
.d3-alert::before {
    content: ""; flex: none;
    width: 6px; height: 6px; border-radius: 50%;
    margin-top: 8px;
    background: currentColor;
}
.d3-alert.is-warn { border-color: rgba(168, 84, 26, .38); background: rgba(168, 84, 26, .07); color: var(--d3-warn); }
.d3-alert.is-bad { border-color: rgba(176, 42, 36, .38); background: rgba(176, 42, 36, .07); color: var(--d3-bad); }
.d3-alert.is-ok { border-color: rgba(29, 107, 79, .34); background: rgba(29, 107, 79, .07); color: var(--d3-ok); }

/* ---------- 9. 正文内容区 ---------- */
.d3-section { padding: 34px 0 0; }

.d3-section > h2 {
    font-size: var(--d3-fs-h2);
    letter-spacing: -.02em;
    margin-bottom: 6px;
}
.d3-section > h2 + p,
.d3-lead { color: var(--d3-ink-2); max-width: 46em; }

.d3-prose { max-width: 46em; }
.d3-prose p { margin-top: 12px; color: var(--d3-ink-2); }
.d3-prose p b { color: var(--d3-ink); }

.d3-cols {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(258px, 1fr));
    gap: 14px;
    margin-top: 16px;
}

/* 含公式块的卡片：单列更宽，避免等宽公式被裁切 */
.d3-cols-wide { grid-template-columns: repeat(auto-fit, minmax(min(420px, 100%), 1fr)); }

.d3-card {
    background: var(--d3-card);
    border: 1px solid var(--d3-line);
    border-radius: var(--d3-radius);
    padding: 16px 18px;
}
.d3-card h3 {
    font-size: var(--d3-fs-h3);
    margin-bottom: 6px;
}
.d3-card p {
    font-size: 14px;
    line-height: 1.8;
    color: var(--d3-ink-2);
}
.d3-card ul {
    margin: 8px 0 0; padding-left: 18px;
    font-size: 14px; line-height: 1.85; color: var(--d3-ink-2);
}
.d3-card li + li { margin-top: 3px; }

/* 公式块 */
.d3-formula {
    font-family: var(--d3-mono);
    font-size: 13px;
    line-height: 2;
    background: var(--d3-paper-2);
    border: 1px solid var(--d3-line);
    border-left: 2px solid var(--d3-accent);
    border-radius: 0 var(--d3-radius-sm) var(--d3-radius-sm) 0;
    padding: 10px 14px;
    margin-top: 12px;
    overflow-x: auto;
    color: var(--d3-ink-2);
    white-space: pre;
}

/* FAQ */
.d3-faq { margin-top: 16px; border-top: 1px solid var(--d3-line); }
.d3-faq details { border-bottom: 1px solid var(--d3-line); }
.d3-faq summary {
    cursor: pointer;
    list-style: none;
    padding: 13px 26px 13px 0;
    position: relative;
    font-weight: 650;
    font-size: 15px;
    color: var(--d3-ink);
}
.d3-faq summary::-webkit-details-marker { display: none; }
.d3-faq summary::after {
    content: "+";
    position: absolute; right: 4px; top: 11px;
    font-family: var(--d3-mono);
    font-size: 17px; font-weight: 400;
    color: var(--d3-accent);
    transition: transform .18s ease;
}
.d3-faq details[open] summary::after { content: "−"; }
.d3-faq .d3-faq-body {
    padding: 0 0 14px;
    font-size: 14px;
    line-height: 1.85;
    color: var(--d3-ink-2);
    max-width: 46em;
}

/* 相关工具 */
.d3-related {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 10px;
    margin-top: 14px;
}
.d3-related a {
    display: flex; align-items: center; gap: 10px;
    padding: 12px 14px;
    background: var(--d3-card);
    border: 1px solid var(--d3-line);
    border-radius: var(--d3-radius-sm);
    color: var(--d3-ink);
    font-size: 14px; font-weight: 600;
    transition: border-color .15s ease, transform .15s ease;
}
.d3-related a:hover {
    border-color: var(--d3-accent);
    text-decoration: none;
    transform: translateY(-1px);
}
.d3-related a span {
    font-family: var(--d3-mono);
    font-size: 11px;
    color: var(--d3-ink-3);
    margin-left: auto;
}

/* ---------- 10. 页脚 ---------- */
.d3-foot {
    margin-top: 46px;
    border-top: 1px solid var(--d3-line);
    padding: 22px 0 30px;
    font-size: 12.5px;
    color: var(--d3-ink-3);
}
.d3-foot-in {
    display: flex; flex-wrap: wrap; gap: 10px 20px; align-items: center;
}
.d3-foot-in p { max-width: 60em; }
.d3-foot-in nav { margin-left: auto; display: flex; gap: 14px; }
.d3-foot-in nav a { color: var(--d3-ink-3); }
.d3-foot-in nav a:hover { color: var(--d3-accent); text-decoration: none; }

/* ---------- 11. 响应式 ---------- */
@media (max-width: 960px) {
    .d3-desk { grid-template-columns: minmax(0, 1fr); }
    .d3-hero { padding-top: 26px; }
}

@media (max-width: 640px) {
    .d3-wrap { padding: 0 16px; }
    .d3-top-in { height: 56px; gap: 10px; }
    .d3-nav > a:first-child { display: none; }
    .d3-seg button { padding: 7px 7px; }
    .d3-fields { grid-template-columns: minmax(0, 1fr); }
    .d3-fields.cols-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .d3-field.span-2 { grid-column: span 1; }
    .d3-kv { grid-template-columns: minmax(0, 1fr); }
    .d3-legend { grid-template-columns: minmax(0, 1fr); }
    .d3-sub { font-size: 15px; }
    .d3-panel-body { padding: 15px; }
    .d3-h1 { letter-spacing: -.02em; }
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after { transition: none !important; animation: none !important; }
}

@media print {
    .d3-top, .d3-foot, .d3-related, .d3-toolbar { display: none; }
    body { background: #fff; }
}