/* ============================================================
   baby-bottle-feed-calc · 奶瓶容量与奶量计算器
   奶瓶刻度风（bbf-）：奶白暖底 + 青瓷绿 + 杏橙，圆角软萌
   ============================================================ */

.bbf-page {
    --bbf-teal: #2ba89c;
    --bbf-teal-deep: #1d7f76;
    --bbf-apricot: #f0954a;
    --bbf-apricot-deep: #d97b2e;
    --bbf-rose: #e2607a;
    --bbf-cream: #faf5ec;
    --bbf-card: #ffffff;
    --bbf-card-2: #fffdf8;
    --bbf-line: #ece2d2;
    --bbf-line-strong: #d8c9b2;
    --bbf-text: #33302a;
    --bbf-muted: #857c6d;
    --bbf-shadow: 0 8px 26px rgba(120, 96, 60, 0.10);
    --bbf-grad: linear-gradient(135deg, #35b8ab 0%, #1d7f76 100%);
    --bbf-grad-warm: linear-gradient(135deg, #f6ad63 0%, #e2607a 100%);

    color: var(--bbf-text);
    font-size: 15px;
    line-height: 1.8;
}

[data-theme="dark"] .bbf-page {
    --bbf-teal: #4cc9bd;
    --bbf-teal-deep: #35a89d;
    --bbf-apricot: #f6b26b;
    --bbf-apricot-deep: #e89a4d;
    --bbf-rose: #f08ba0;
    --bbf-cream: #211e18;
    --bbf-card: #2b271f;
    --bbf-card-2: #302b22;
    --bbf-line: #453e31;
    --bbf-line-strong: #5d5342;
    --bbf-text: #f0e9dc;
    --bbf-muted: #b3a88f;
    --bbf-shadow: 0 8px 26px rgba(0, 0, 0, 0.35);
    --bbf-grad: linear-gradient(135deg, #35a89d 0%, #1f6d66 100%);
}

.bbf-page h1, .bbf-page h2, .bbf-page h3 { line-height: 1.4; }
.bbf-page b, .bbf-page strong { color: var(--bbf-teal-deep); }

/* ---------- 首屏 ---------- */
.bbf-hero {
    position: relative;
    display: grid;
    grid-template-columns: minmax(0, 1.5fr) auto minmax(230px, 0.8fr);
    gap: 26px 30px;
    align-items: center;
    padding: 32px 32px 28px;
    margin-bottom: 26px;
    border: 1px solid var(--bbf-line);
    border-radius: 28px;
    background:
        radial-gradient(90% 120% at 100% 0%, rgba(240, 149, 74, 0.10), transparent 55%),
        radial-gradient(70% 100% at 0% 100%, rgba(43, 168, 156, 0.10), transparent 55%),
        var(--bbf-card);
    box-shadow: var(--bbf-shadow);
}
.bbf-kicker {
    display: inline-block;
    padding: 5px 16px;
    margin-bottom: 14px;
    border-radius: 999px;
    background: rgba(43, 168, 156, 0.12);
    color: var(--bbf-teal-deep);
    font-size: 12.5px;
    font-weight: 700;
    letter-spacing: 0.1em;
}
.bbf-hero h1 {
    margin: 0 0 12px;
    font-size: clamp(26px, 3.4vw, 38px);
    font-weight: 900;
    letter-spacing: 0.01em;
}
.bbf-hero-sub {
    margin: 0 0 16px;
    max-width: 60ch;
    color: var(--bbf-muted);
    font-size: 15.5px;
}
.bbf-hero-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 0;
    padding: 0;
    list-style: none;
}
.bbf-hero-chips li {
    padding: 5px 14px;
    border-radius: 999px;
    border: 1px solid var(--bbf-line);
    background: var(--bbf-card-2);
    color: var(--bbf-muted);
    font-size: 12.5px;
    font-weight: 600;
}

/* hero 奶瓶装饰 */
.bbf-hero-bottle {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 4px 8px;
}
.bbf-bottle-cap {
    width: 46px;
    height: 26px;
    border-radius: 14px 14px 6px 6px;
    background: var(--bbf-grad-warm);
    box-shadow: 0 3px 8px rgba(226, 96, 122, 0.3);
}
.bbf-bottle-neck {
    width: 34px;
    height: 12px;
    background: var(--bbf-line-strong);
    border-radius: 0 0 6px 6px;
}
.bbf-bottle-body {
    position: relative;
    width: 96px;
    height: 190px;
    margin-top: 4px;
    border: 3px solid var(--bbf-line-strong);
    border-radius: 20px 20px 26px 26px;
    background: var(--bbf-card-2);
    overflow: hidden;
}
.bbf-bottle-milk {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 62%;
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.55), transparent 40%),
        linear-gradient(180deg, #fdf3e0, #f7e3bd);
    animation: bbf-slosh 5s ease-in-out infinite;
}
[data-theme="dark"] .bbf-bottle-milk {
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.14), transparent 40%),
        linear-gradient(180deg, #d8bd8a, #b98f4e);
}
@keyframes bbf-slosh {
    0%, 100% { height: 62%; }
    50% { height: 58%; }
}
@media (prefers-reduced-motion: reduce) {
    .bbf-bottle-milk { animation: none; }
}
.bbf-bottle-tick {
    position: absolute;
    left: 8px;
    font-size: 10px;
    font-weight: 800;
    color: var(--bbf-muted);
    font-family: ui-monospace, Consolas, monospace;
}
.bbf-bottle-tick::before {
    content: "";
    position: absolute;
    left: -6px;
    right: -60px;
    top: 50%;
    border-top: 1.5px dashed var(--bbf-line-strong);
}
.bbf-bottle-tick.t240 { bottom: 84%; }
.bbf-bottle-tick.t180 { bottom: 60%; }
.bbf-bottle-tick.t120 { bottom: 36%; }
.bbf-bottle-tick.t60 { bottom: 12%; }

/* hero 读数卡 */
.bbf-hero-readout {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 20px 22px;
    border-radius: 24px;
    border: 2px solid var(--bbf-teal);
    background: var(--bbf-card);
    box-shadow: var(--bbf-shadow);
}
.bbf-readout-label {
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.1em;
    color: var(--bbf-teal-deep);
}
.bbf-readout-num {
    font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
    font-size: 33px;
    font-weight: 900;
    line-height: 1.15;
    color: var(--bbf-teal-deep);
}
.bbf-readout-avg { font-size: 14px; font-weight: 700; }
.bbf-readout-meta { font-size: 12.5px; color: var(--bbf-muted); }
.bbf-readout-tip {
    margin-top: 6px;
    padding-top: 8px;
    border-top: 1px dashed var(--bbf-line);
    font-size: 11.5px;
    color: var(--bbf-muted);
}

/* ---------- 测算区 ---------- */
.bbf-calc {
    display: grid;
    grid-template-columns: minmax(0, 1.25fr) minmax(320px, 0.85fr);
    gap: 24px;
    align-items: start;
    margin-bottom: 30px;
}
.bbf-input-col { display: grid; gap: 22px; }
.bbf-panel {
    padding: 24px 26px;
    border: 1px solid var(--bbf-line);
    border-radius: 26px;
    background: var(--bbf-card);
    box-shadow: var(--bbf-shadow);
}
.bbf-panel-head {
    display: flex;
    gap: 14px;
    align-items: flex-start;
    margin-bottom: 18px;
    padding-bottom: 14px;
    border-bottom: 1px dashed var(--bbf-line);
}
.bbf-step {
    flex: none;
    display: grid;
    place-items: center;
    width: 38px;
    height: 38px;
    border-radius: 50%;
    background: var(--bbf-grad);
    color: #fff;
    font-family: ui-monospace, Consolas, monospace;
    font-size: 15px;
    font-weight: 800;
    box-shadow: 0 4px 10px rgba(43, 168, 156, 0.35);
}
.bbf-panel-head h2 { margin: 0 0 3px; font-size: 18px; font-weight: 900; }
.bbf-panel-head p { margin: 0; color: var(--bbf-muted); font-size: 13px; }

.bbf-grid2 { display: grid; gap: 14px; grid-template-columns: repeat(2, minmax(0, 1fr)); margin-bottom: 12px; }
.bbf-grid3 { display: grid; gap: 14px; grid-template-columns: repeat(3, minmax(0, 1fr)); margin-bottom: 12px; }

.bbf-field { display: flex; flex-direction: column; gap: 5px; }
.bbf-label { font-size: 12.5px; font-weight: 700; color: var(--bbf-muted); }
.bbf-input-wrap, .bbf-select-wrap { position: relative; display: block; }
.bbf-input {
    width: 100%;
    padding: 10px 46px 10px 14px;
    border: 2px solid var(--bbf-line);
    border-radius: 16px;
    background: var(--bbf-card-2);
    color: var(--bbf-text);
    font-size: 14.5px;
    font-weight: 600;
    font-family: ui-monospace, Consolas, monospace;
    transition: border-color 0.18s, box-shadow 0.18s;
}
select.bbf-input { padding-right: 32px; appearance: none; cursor: pointer; }
.bbf-select-wrap::after {
    content: "▾";
    position: absolute;
    right: 13px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--bbf-muted);
    font-size: 12px;
    pointer-events: none;
}
.bbf-input:focus {
    outline: none;
    border-color: var(--bbf-teal);
    box-shadow: 0 0 0 3px rgba(43, 168, 156, 0.16);
}
.bbf-input.is-invalid {
    border-color: var(--bbf-rose);
    box-shadow: 0 0 0 3px rgba(226, 96, 122, 0.15);
}
.bbf-unit {
    position: absolute;
    right: 14px;
    top: 50%;
    transform: translateY(-50%);
    font-style: normal;
    font-size: 12px;
    color: var(--bbf-muted);
    pointer-events: none;
}
.bbf-age-ref {
    margin: 4px 0 8px;
    padding: 10px 16px;
    border-radius: 16px;
    background: rgba(240, 149, 74, 0.10);
    border: 1px dashed var(--bbf-apricot);
    color: var(--bbf-apricot-deep);
    font-size: 13px;
    font-weight: 700;
    line-height: 1.7;
}
.bbf-hint {
    margin: 8px 0 0;
    color: var(--bbf-muted);
    font-size: 12.5px;
    line-height: 1.7;
}

/* 奶瓶规格批量输入 */
.bbf-specgrid { display: grid; gap: 10px; margin-bottom: 14px; }
.bbf-specrow {
    display: grid;
    grid-template-columns: 92px minmax(0, 1fr) minmax(0, 1.5fr);
    gap: 12px;
    align-items: center;
}
.bbf-specrow-name {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    font-weight: 800;
    color: var(--bbf-text);
}
.bbf-spec-dot {
    flex: none;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--bbf-grad);
    box-shadow: 0 0 0 3px rgba(43, 168, 156, 0.15);
}
.bbf-specrow .bbf-input { padding-right: 40px; }
.bbf-specnote { font-size: 12px; color: var(--bbf-muted); }

/* 报错 + 按钮 */
.bbf-error {
    margin: 4px 0 12px;
    padding: 11px 16px;
    border-radius: 16px;
    border: 1.5px solid rgba(226, 96, 122, 0.4);
    background: rgba(226, 96, 122, 0.08);
    color: var(--bbf-rose);
    font-size: 13px;
    font-weight: 700;
    line-height: 1.6;
}
.bbf-actions, .bbf-result-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 14px; }
.bbf-btn {
    padding: 10px 22px;
    border: 2px solid var(--bbf-line-strong);
    border-radius: 999px;
    background: var(--bbf-card);
    color: var(--bbf-text);
    font-size: 14px;
    font-weight: 800;
    cursor: pointer;
    transition: transform 0.15s, box-shadow 0.15s, border-color 0.15s;
}
.bbf-btn:hover { transform: translateY(-1px); border-color: var(--bbf-teal); }
.bbf-btn--primary {
    border-color: transparent;
    background: var(--bbf-grad);
    color: #fff;
    box-shadow: 0 6px 16px rgba(43, 168, 156, 0.35);
}
.bbf-btn--primary:hover { box-shadow: 0 9px 20px rgba(43, 168, 156, 0.45); }

/* ---------- 结果列 ---------- */
.bbf-result-col {
    position: sticky;
    top: 84px;
    display: grid;
    gap: 16px;
}
.bbf-result-hero {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 22px 24px;
    border-radius: 26px;
    background: var(--bbf-grad);
    color: #fff;
    box-shadow: 0 10px 26px rgba(43, 168, 156, 0.4);
}
.bbf-rh-label { font-size: 12.5px; font-weight: 700; letter-spacing: 0.1em; opacity: 0.85; }
.bbf-rh-num {
    font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
    font-size: 36px;
    font-weight: 900;
    line-height: 1.2;
}
.bbf-rh-sub { font-size: 13px; font-weight: 600; opacity: 0.92; }
.bbf-result-hero b { color: #fff; }

.bbf-kpis { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.bbf-kpi {
    display: flex;
    flex-direction: column;
    gap: 3px;
    padding: 14px 16px;
    border: 1px solid var(--bbf-line);
    border-radius: 20px;
    background: var(--bbf-card);
    box-shadow: var(--bbf-shadow);
}
.bbf-kpi span { font-size: 12px; font-weight: 700; color: var(--bbf-muted); }
.bbf-kpi b {
    font-family: ui-monospace, Consolas, monospace;
    font-size: 19px;
    font-weight: 900;
    color: var(--bbf-apricot-deep);
}
.bbf-kpi small { font-size: 11px; color: var(--bbf-muted); }

.bbf-verdict { display: grid; gap: 10px; }
.bbf-verdict-item {
    display: flex;
    gap: 10px;
    align-items: flex-start;
    padding: 12px 16px;
    border-radius: 18px;
    border: 1.5px solid var(--bbf-line);
    background: var(--bbf-card);
    font-size: 13px;
    line-height: 1.75;
    box-shadow: var(--bbf-shadow);
}
.bbf-verdict-item .bbf-vi-icon { flex: none; font-size: 16px; line-height: 1.6; }
.bbf-verdict-item.is-teal { border-color: rgba(43, 168, 156, 0.45); background: rgba(43, 168, 156, 0.07); }
.bbf-verdict-item.is-apricot { border-color: rgba(240, 149, 74, 0.5); background: rgba(240, 149, 74, 0.08); }
.bbf-verdict-item.is-rose { border-color: rgba(226, 96, 122, 0.5); background: rgba(226, 96, 122, 0.07); }

.bbf-mini-card {
    padding: 18px 20px;
    border: 1px solid var(--bbf-line);
    border-radius: 22px;
    background: var(--bbf-card);
    box-shadow: var(--bbf-shadow);
}
.bbf-mini-card h3 { margin: 0 0 10px; font-size: 14.5px; font-weight: 900; }

.bbf-table-scroll { overflow-x: auto; }
.bbf-table { width: 100%; border-collapse: collapse; font-size: 12.8px; }
.bbf-mini-card .bbf-table { font-size: 12.5px; }
.bbf-table th {
    padding: 8px 10px;
    text-align: left;
    border-bottom: 2px solid var(--bbf-line-strong);
    color: var(--bbf-teal-deep);
    font-size: 12px;
    font-weight: 800;
    white-space: nowrap;
}
.bbf-table td {
    padding: 8px 10px;
    border-bottom: 1px solid var(--bbf-line);
    font-family: ui-monospace, Consolas, monospace;
    white-space: nowrap;
}
.bbf-table td:first-child { font-family: inherit; font-weight: 700; }
.bbf-table tbody tr:hover { background: rgba(43, 168, 156, 0.05); }
.bbf-table .is-good { color: var(--bbf-teal-deep); font-weight: 800; }
.bbf-table .is-warn { color: var(--bbf-apricot-deep); font-weight: 800; }
.bbf-table .is-bad { color: var(--bbf-rose); font-weight: 800; }
.bbf-table .is-dim { color: var(--bbf-muted); }
.bbf-table-empty { text-align: center; color: var(--bbf-muted); font-family: inherit; }
.bbf-result-foot { margin: 0; font-size: 12px; color: var(--bbf-muted); }

/* ---------- A4 记录卡 ---------- */
.bbf-sheet-wrap { margin-bottom: 34px; }
.bbf-sheet-head {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: flex-end;
    gap: 12px;
    margin-bottom: 16px;
}
.bbf-sheet-kicker {
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.14em;
    color: var(--bbf-apricot-deep);
    text-transform: uppercase;
}
.bbf-sheet-head h2 { margin: 4px 0 6px; font-size: 22px; font-weight: 900; }
.bbf-sheet-head p { margin: 0; max-width: 62ch; color: var(--bbf-muted); font-size: 13px; }
.bbf-sheet-badge {
    padding: 5px 14px;
    border-radius: 999px;
    border: 1px dashed var(--bbf-line-strong);
    color: var(--bbf-muted);
    font-size: 12px;
    font-weight: 700;
}

.bbf-sheet {
    padding: 30px 34px;
    border: 1px solid var(--bbf-line);
    border-radius: 16px;
    background: #fffdf8;
    color: #3a352c;
    box-shadow: var(--bbf-shadow);
    font-size: 13px;
    line-height: 1.65;
}
[data-theme="dark"] .bbf-sheet { background: #fffdf8; color: #3a352c; }
.bbf-sheet-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 16px;
    padding-bottom: 12px;
    border-bottom: 3px double #2ba89c;
}
.bbf-sheet-top h3 { margin: 0 0 3px; font-size: 18px; color: #1d7f76; }
.bbf-sheet-top p { margin: 0; font-size: 12px; color: #8a8172; }
.bbf-sheet-meta { text-align: right; font-size: 12px; color: #6b6353; display: flex; flex-direction: column; gap: 3px; }
.bbf-sheet-meta b { font-family: ui-monospace, Consolas, monospace; color: #1d7f76; }
.bbf-sheet-info {
    display: grid;
    grid-template-columns: repeat(4, auto);
    justify-content: space-between;
    gap: 8px 22px;
    padding: 12px 0;
    border-bottom: 1px solid #e7dcc8;
    font-size: 12.5px;
    color: #6b6353;
}
.bbf-sheet-info b { font-family: ui-monospace, Consolas, monospace; color: #1d7f76; }
.bbf-sheet-big {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    margin: 14px 0;
}
.bbf-sheet-big-item {
    display: flex;
    flex-direction: column;
    gap: 3px;
    padding: 10px 12px;
    border: 1.5px solid #cdeae6;
    border-radius: 12px;
    background: #f2faf8;
}
.bbf-sheet-big-item span { font-size: 11px; font-weight: 700; color: #6b6353; }
.bbf-sheet-big-item b { font-family: ui-monospace, Consolas, monospace; font-size: 14px; color: #1d7f76; }
.bbf-sheet-table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: 12.5px; }
.bbf-sheet-table th {
    padding: 7px 10px;
    text-align: left;
    background: #eaf6f4;
    border: 1px solid #cdeae6;
    color: #1d7f76;
    font-weight: 800;
}
.bbf-sheet-table td { padding: 7px 10px; border: 1px solid #e7dcc8; font-family: ui-monospace, Consolas, monospace; }
.bbf-sheet-table td:nth-child(2) { font-family: inherit; }
.bbf-sheet-table .w-no { width: 42px; }
.bbf-sheet-table .w-sub { width: 100px; }
.bbf-sheet-notes { padding: 12px 14px; border-radius: 12px; background: #fdf3e3; font-size: 11.5px; color: #7a6a4c; }
.bbf-sheet-notes p { margin: 0 0 6px; }
.bbf-sheet-notes p:last-child { margin-bottom: 0; }
.bbf-sheet-notes b { color: #d97b2e; }
.bbf-sheet-foot { margin-top: 14px; text-align: center; font-size: 11px; color: #a89e8a; }

/* ---------- 参考 / 规则 / FAQ ---------- */
.bbf-reference, .bbf-rules, .bbf-faq { margin-bottom: 34px; }
.bbf-section-head { margin-bottom: 18px; }
.bbf-section-kicker {
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.16em;
    color: var(--bbf-apricot-deep);
    text-transform: uppercase;
}
.bbf-section-head h2 { margin: 6px 0 6px; font-size: 23px; font-weight: 900; }
.bbf-section-head p { margin: 0; color: var(--bbf-muted); font-size: 13.5px; }

.bbf-ref-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.bbf-ref-card {
    padding: 20px 22px;
    border: 1px solid var(--bbf-line);
    border-radius: 24px;
    background: var(--bbf-card);
    box-shadow: var(--bbf-shadow);
}
.bbf-ref-card h3 { margin: 0 0 2px; font-size: 16px; font-weight: 900; }
.bbf-ref-sub { margin: 0 0 12px; font-size: 12px; color: var(--bbf-muted); }
.bbf-ref-card .bbf-table { min-width: 0; }
.bbf-ref-card .bbf-table td.is-price { color: var(--bbf-teal-deep); font-weight: 800; }
.bbf-ref-tip { margin: 12px 0 0; font-size: 12.5px; color: var(--bbf-muted); line-height: 1.7; }
.bbf-ref-note {
    margin: 16px 0 0;
    padding: 13px 18px;
    border-radius: 20px;
    border: 1px dashed var(--bbf-teal);
    background: rgba(43, 168, 156, 0.06);
    font-size: 13px;
    color: var(--bbf-muted);
    line-height: 1.8;
}
.bbf-ref-note b { color: var(--bbf-teal-deep); }

.bbf-rule-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; margin-bottom: 18px; }
.bbf-rule {
    padding: 18px;
    border: 1px solid var(--bbf-line);
    border-radius: 22px;
    background: var(--bbf-card);
    box-shadow: var(--bbf-shadow);
}
.bbf-rule-no {
    display: inline-grid;
    place-items: center;
    width: 30px;
    height: 30px;
    margin-bottom: 10px;
    border-radius: 50%;
    background: rgba(240, 149, 74, 0.16);
    color: var(--bbf-apricot-deep);
    font-size: 15px;
    font-weight: 800;
}
.bbf-rule h3 { margin: 0 0 6px; font-size: 15px; font-weight: 900; }
.bbf-rule p { margin: 0; font-size: 12.5px; color: var(--bbf-muted); line-height: 1.75; }

.bbf-example {
    padding: 20px 24px;
    border-radius: 24px;
    border: 1px solid var(--bbf-line-strong);
    background:
        radial-gradient(80% 120% at 100% 0%, rgba(240, 149, 74, 0.12), transparent 60%),
        var(--bbf-card-2);
}
.bbf-example h3 { margin: 0 0 8px; font-size: 16px; font-weight: 900; }
.bbf-example p { margin: 0 0 8px; font-size: 13.5px; line-height: 1.9; }
.bbf-example-note { color: var(--bbf-muted); font-size: 12.5px; }

.bbf-faq .faq-list { display: grid; gap: 12px; }
.bbf-faq .faq-item {
    border: 1px solid var(--bbf-line);
    border-radius: 20px;
    background: var(--bbf-card);
    padding: 4px 20px;
    box-shadow: none;
}
.bbf-faq .faq-item summary { font-weight: 800; font-size: 14.5px; }
.bbf-faq .faq-a { font-size: 13.5px; color: var(--bbf-muted); line-height: 1.9; }

/* 返回顶部 */
.bbf-top {
    position: fixed;
    right: 22px;
    bottom: 26px;
    width: 44px;
    height: 44px;
    border: none;
    border-radius: 50%;
    background: var(--bbf-grad);
    color: #fff;
    font-size: 18px;
    font-weight: 800;
    cursor: pointer;
    box-shadow: 0 8px 20px rgba(43, 168, 156, 0.4);
    opacity: 0;
    transform: translateY(12px);
    pointer-events: none;
    transition: opacity 0.25s, transform 0.25s;
    z-index: 60;
}
.bbf-top.is-show { opacity: 1; transform: none; pointer-events: auto; }

/* ---------- 响应式 ---------- */
@media (max-width: 1020px) {
    .bbf-hero { grid-template-columns: 1fr; }
    .bbf-hero-bottle { display: none; }
    .bbf-calc { grid-template-columns: 1fr; }
    .bbf-result-col { position: static; }
    .bbf-grid3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .bbf-ref-grid, .bbf-rule-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 620px) {
    .bbf-hero { padding: 22px 18px; border-radius: 22px; }
    .bbf-panel, .bbf-mini-card { padding: 16px 14px; }
    .bbf-grid2, .bbf-grid3 { grid-template-columns: 1fr; }
    .bbf-kpis { grid-template-columns: 1fr 1fr; }
    .bbf-ref-grid, .bbf-rule-grid { grid-template-columns: 1fr; }
    .bbf-specrow { grid-template-columns: 80px minmax(0, 1fr) minmax(0, 1.2fr); gap: 8px; }
    .bbf-sheet { padding: 20px 16px; }
    .bbf-sheet-info, .bbf-sheet-big { grid-template-columns: 1fr 1fr; }
}

/* ---------- 打印：仅 A4 记录卡 ---------- */
@media print {
    .bbf-page .bbf-hero, .bbf-page .bbf-calc, .bbf-page .bbf-reference,
    .bbf-page .bbf-rules, .bbf-page .bbf-faq, .bbf-page .related,
    .bbf-page .bbf-comments, .bbf-sheet-head, .bbf-top, .detail-breadcrumb {
        display: none !important;
    }
    .bbf-sheet-wrap { margin: 0; }
    .bbf-sheet { border: none; border-radius: 0; box-shadow: none; padding: 0; }
    .detail-wrap, .container { padding: 0; margin: 0; max-width: none; }
}