/* =========================================
   Differential Robotics Report — Styles
   基于 Wise-BJ 视觉语言扩展
   ========================================= */

:root {
    --color-bg: #fafaf8;
    --color-surface: #f3f3ee;
    --color-surface-2: #ececdf;
    --color-ink: #0a0a0a;
    --color-ink-soft: #3d3d3d;
    --color-ink-soft-2: #5a5a5a;
    --color-muted: #8a8a8a;
    --color-line: #e6e6e0;
    --color-line-soft: #efefe8;
    --color-accent: #1f3a2e;
    --color-accent-soft: #e8efe9;
    --color-accent-bright: #5fa777;
    --color-warn: #8b5a2b;
    --color-warn-soft: #f5ecdb;
    --color-danger: #8b2c2c;
    --color-danger-soft: #f5dfdf;

    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial,
        sans-serif;
    --font-serif: "Noto Serif SC", "Songti SC", "STSong", Georgia,
        "Times New Roman", serif;
    --font-mono: "SF Mono", "Menlo", "Consolas", "Liberation Mono", monospace;

    --radius-sm: 6px;
    --radius-md: 10px;
    --max-width: 1200px;
    --content-width: 760px;
}

/* --- Reset / base --- */
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
img, svg { display: block; max-width: 100%; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
    font-family: var(--font-sans);
    color: var(--color-ink);
    background: var(--color-bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-feature-settings: "kern", "liga";
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: opacity 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}
a:hover { opacity: 0.72; }

h1, h2, h3, h4, h5, h6 { font-weight: 500; letter-spacing: -0.005em; }
p { margin: 0 0 1em; }

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 32px;
}
.container-narrow {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 32px;
}

/* --- Header --- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(250, 250, 248, 0.92);
    backdrop-filter: saturate(180%) blur(12px);
    -webkit-backdrop-filter: saturate(180%) blur(12px);
    border-bottom: 1px solid var(--color-line);
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 24px;
}
.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--color-ink);
    text-decoration: none;
}
.brand:hover { opacity: 1; }
.brand-mark {
    width: 22px;
    height: 22px;
    color: inherit;
}
.brand-meta {
    font-size: 0.78rem;
    color: var(--color-muted);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    font-weight: 500;
}

/* --- Hero --- */
.hero {
    position: relative;
    padding: 88px 0 64px;
    background:
        radial-gradient(ellipse at 80% -10%, var(--color-accent-soft), transparent 55%),
        var(--color-bg);
    border-bottom: 1px solid var(--color-line);
    overflow: hidden;
}
.eyebrow {
    font-size: 0.78rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--color-accent);
    margin: 0 0 20px;
    font-weight: 600;
}
.hero-title {
    font-family: var(--font-serif);
    font-size: clamp(2rem, 4.6vw, 3.4rem);
    line-height: 1.18;
    font-weight: 500;
    margin: 0 0 24px;
    max-width: 22ch;
}
.hero-sub {
    font-size: 1.15rem;
    color: var(--color-ink-soft);
    max-width: 56ch;
    margin: 0 0 36px;
    line-height: 1.75;
}
.hero-meta {
    display: flex;
    gap: 36px;
    flex-wrap: wrap;
    border-top: 1px solid var(--color-line);
    padding-top: 28px;
    margin-top: 32px;
    font-size: 0.88rem;
}
.hero-meta-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.hero-meta-label {
    font-size: 0.72rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--color-muted);
    font-weight: 600;
}
.hero-meta-value {
    color: var(--color-ink);
    font-weight: 500;
}

/* --- Layout: main with sidebar TOC --- */
.layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 48px;
    padding: 64px 32px 96px;
    max-width: var(--max-width);
    margin: 0 auto;
}
@media (min-width: 1000px) {
    .layout {
        grid-template-columns: 220px minmax(0, 1fr);
        gap: 64px;
    }
}

.toc {
    position: sticky;
    top: 96px;
    align-self: start;
    font-size: 0.86rem;
    line-height: 1.5;
    display: none;
}
@media (min-width: 1000px) {
    .toc { display: block; }
}
.toc-title {
    font-size: 0.72rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--color-muted);
    margin: 0 0 14px;
    font-weight: 600;
}
.toc ol {
    list-style: none;
    margin: 0;
    padding: 0;
    counter-reset: toc;
}
.toc li {
    counter-increment: toc;
    margin: 0 0 8px;
}
.toc li a {
    display: block;
    color: var(--color-ink-soft);
    padding: 4px 0 4px 28px;
    position: relative;
    border-left: 1px solid var(--color-line);
    transition: all 0.18s ease;
}
.toc li a::before {
    content: counter(toc, decimal-leading-zero);
    position: absolute;
    left: 8px;
    top: 4px;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--color-muted);
}
.toc li a:hover {
    color: var(--color-ink);
    opacity: 1;
    border-left-color: var(--color-accent);
}

/* --- Content --- */
.content {
    max-width: var(--content-width);
}
.content > section {
    padding: 56px 0;
    border-top: 1px solid var(--color-line);
}
.content > section:first-child { border-top: none; padding-top: 0; }

.section-num {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.18em;
    color: var(--color-accent);
    font-weight: 600;
    margin: 0 0 16px;
}
.content h2 {
    font-family: var(--font-serif);
    font-size: clamp(1.7rem, 3.2vw, 2.3rem);
    line-height: 1.25;
    margin: 0 0 24px;
}
.content h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin: 36px 0 14px;
    line-height: 1.4;
}
.content h4 {
    font-size: 1.02rem;
    font-weight: 600;
    margin: 28px 0 10px;
    color: var(--color-ink-soft);
}
.content p {
    font-size: 1rem;
    color: var(--color-ink-soft);
    margin: 0 0 16px;
    line-height: 1.75;
}
.content p strong { color: var(--color-ink); font-weight: 600; }
.content ul, .content ol {
    color: var(--color-ink-soft);
    padding-left: 22px;
    margin: 0 0 16px;
}
.content li {
    margin: 0 0 8px;
    line-height: 1.7;
}
.content li::marker {
    color: var(--color-accent);
}

/* Lead paragraph */
.lead {
    font-size: 1.12rem;
    line-height: 1.75;
    color: var(--color-ink-soft);
    border-left: 3px solid var(--color-accent);
    padding-left: 20px;
    margin: 0 0 32px;
    max-width: 56ch;
}

/* --- Tables --- */
.table-wrap {
    margin: 24px 0 28px;
    overflow-x: auto;
    border: 1px solid var(--color-line);
    border-radius: var(--radius-sm);
}
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.92rem;
}
th, td {
    text-align: left;
    padding: 12px 16px;
    border-bottom: 1px solid var(--color-line);
    vertical-align: top;
    line-height: 1.55;
}
th {
    background: var(--color-surface);
    font-weight: 600;
    color: var(--color-ink);
    font-size: 0.82rem;
    letter-spacing: 0.04em;
}
tr:last-child td { border-bottom: none; }
td { color: var(--color-ink-soft); }
td strong { color: var(--color-ink); font-weight: 600; }
.table-compact th, .table-compact td { padding: 8px 12px; font-size: 0.86rem; }

/* --- Key Findings / Callout cards --- */
.callout {
    background: var(--color-surface);
    border-left: 4px solid var(--color-accent);
    padding: 24px 28px;
    margin: 24px 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.callout p:last-child { margin-bottom: 0; }
.callout h4 {
    margin: 0 0 8px;
    color: var(--color-accent);
    font-size: 0.78rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
}
.callout-warn {
    background: var(--color-warn-soft);
    border-left-color: var(--color-warn);
}
.callout-warn h4 { color: var(--color-warn); }
.callout-danger {
    background: var(--color-danger-soft);
    border-left-color: var(--color-danger);
}
.callout-danger h4 { color: var(--color-danger); }

/* --- Trap cards (5 大陷阱) --- */
.trap-card {
    background: #fff;
    border: 1px solid var(--color-line);
    border-left: 4px solid var(--color-danger);
    border-radius: var(--radius-sm);
    padding: 22px 24px;
    margin: 0 0 16px;
}
.trap-num {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.18em;
    color: var(--color-danger);
    font-weight: 600;
    margin: 0 0 8px;
}
.trap-card h4 {
    font-size: 1.05rem;
    margin: 0 0 12px;
    color: var(--color-ink);
}
.trap-card .vs {
    font-size: 0.86rem;
    margin: 0 0 8px;
}
.trap-card .vs .label {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    color: var(--color-muted);
    width: 64px;
}
.trap-card .vs .text-wrong { color: var(--color-danger); }
.trap-card .vs .text-right { color: var(--color-accent); }
.trap-card .warning {
    margin: 12px 0 0;
    padding-top: 12px;
    border-top: 1px dashed var(--color-line);
    font-size: 0.92rem;
    color: var(--color-ink-soft);
}
.trap-card .warning::before {
    content: "→ 警示：";
    font-weight: 600;
    color: var(--color-danger);
}

/* --- Method cards (6 大方法论) --- */
.method-card {
    background: #fff;
    border: 1px solid var(--color-line);
    border-left: 4px solid var(--color-accent);
    border-radius: var(--radius-sm);
    padding: 22px 24px;
    margin: 0 0 16px;
}
.method-num {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.18em;
    color: var(--color-accent);
    font-weight: 600;
    margin: 0 0 8px;
}
.method-card h4 {
    font-size: 1.05rem;
    margin: 0 0 12px;
}
.method-card .star {
    color: var(--color-accent);
    margin-left: 4px;
    font-size: 0.85rem;
}
.method-card .row {
    font-size: 0.92rem;
    color: var(--color-ink-soft);
    margin: 6px 0;
}
.method-card .row .label {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    color: var(--color-muted);
    width: 80px;
}

/* --- Stage timeline (5 阶段) --- */
.stage {
    padding: 28px 0;
    border-top: 1px solid var(--color-line);
    display: grid;
    grid-template-columns: 120px 1fr;
    gap: 32px;
}
.stage:last-child { border-bottom: 1px solid var(--color-line); }
.stage-num {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.18em;
    color: var(--color-accent);
    font-weight: 600;
    padding-top: 6px;
}
.stage-num small {
    display: block;
    font-size: 0.7rem;
    letter-spacing: 0.06em;
    color: var(--color-muted);
    margin-top: 6px;
    font-weight: 500;
    text-transform: none;
}
.stage-content h3 {
    margin-top: 0;
    font-size: 1.2rem;
}
.stage-content .stage-meta {
    font-size: 0.86rem;
    color: var(--color-muted);
    margin: 0 0 16px;
    font-family: var(--font-mono);
    letter-spacing: 0.04em;
}
@media (max-width: 700px) {
    .stage {
        grid-template-columns: 1fr;
        gap: 12px;
    }
}

/* --- Investor quote cards --- */
.quote {
    margin: 24px 0;
    padding: 22px 28px;
    background: var(--color-surface);
    border-radius: var(--radius-sm);
    font-style: italic;
    color: var(--color-ink-soft);
    border-left: 3px solid var(--color-accent);
}
.quote .source {
    display: block;
    margin-top: 12px;
    font-style: normal;
    font-size: 0.84rem;
    color: var(--color-muted);
    letter-spacing: 0.02em;
}

/* --- Financing timeline --- */
.timeline {
    position: relative;
    margin: 32px 0;
    padding-left: 0;
}
.timeline-row {
    display: grid;
    grid-template-columns: 110px 1fr;
    gap: 20px;
    padding: 18px 0;
    border-top: 1px solid var(--color-line);
    align-items: start;
}
.timeline-row:last-child { border-bottom: 1px solid var(--color-line); }
.timeline-when {
    font-family: var(--font-mono);
    font-size: 0.84rem;
    color: var(--color-accent);
    font-weight: 600;
    padding-top: 4px;
}
.timeline-when small {
    display: block;
    color: var(--color-muted);
    font-weight: 500;
    font-size: 0.72rem;
    margin-top: 4px;
}
.timeline-body strong { font-weight: 600; color: var(--color-ink); }
.timeline-body .amount {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.86rem;
    color: var(--color-accent);
    background: var(--color-accent-soft);
    padding: 1px 8px;
    border-radius: 3px;
    margin-right: 8px;
}
.timeline-body p { margin: 4px 0 0; font-size: 0.92rem; }

/* --- Comparison rows (故事 vs 事实) --- */
.compare-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    padding: 18px 0;
    border-top: 1px solid var(--color-line);
    font-size: 0.92rem;
}
.compare-row:last-child { border-bottom: 1px solid var(--color-line); }
.compare-row .story {
    color: var(--color-ink-soft);
}
.compare-row .truth {
    color: var(--color-danger);
    font-weight: 500;
}
.compare-row .truth.confirmed {
    color: var(--color-accent);
}
.compare-header {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    padding: 12px 0;
    font-family: var(--font-mono);
    font-size: 0.74rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--color-muted);
    font-weight: 600;
    border-bottom: 2px solid var(--color-ink);
}

/* --- Constraint formula --- */
.formula {
    background: var(--color-ink);
    color: #f0f0e8;
    padding: 20px 24px;
    margin: 24px 0;
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.92rem;
    line-height: 1.7;
    white-space: pre;
    overflow-x: auto;
}
.formula .acc { color: var(--color-accent-bright); }

/* --- Hypothesis matrix --- */
.hyp-row {
    display: grid;
    grid-template-columns: 60px 1fr 100px 100px;
    gap: 16px;
    padding: 14px 0;
    border-top: 1px solid var(--color-line);
    align-items: center;
    font-size: 0.92rem;
}
.hyp-row:last-child { border-bottom: 1px solid var(--color-line); }
.hyp-head {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--color-muted);
    font-weight: 600;
    border-bottom: 2px solid var(--color-ink);
    padding-bottom: 8px;
}
.hyp-id {
    font-family: var(--font-mono);
    font-weight: 600;
    color: var(--color-accent);
}
.hyp-strength, .hyp-conf {
    font-family: var(--font-mono);
    font-size: 0.84rem;
    text-align: center;
    padding: 3px 8px;
    border-radius: 3px;
    font-weight: 600;
}
.s-strong { background: var(--color-danger-soft); color: var(--color-danger); }
.s-moderate { background: var(--color-warn-soft); color: var(--color-warn); }
.s-low { background: var(--color-accent-soft); color: var(--color-accent); }
@media (max-width: 700px) {
    .hyp-row, .hyp-head {
        grid-template-columns: 50px 1fr;
        gap: 10px;
    }
    .hyp-strength, .hyp-conf { display: none; }
}

/* --- Forecast cards --- */
.forecast {
    background: #fff;
    border: 1px solid var(--color-line);
    border-radius: var(--radius-sm);
    padding: 20px 24px;
    margin: 0 0 14px;
}
.forecast-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 0 0 12px;
    flex-wrap: wrap;
    gap: 8px;
}
.forecast-title {
    font-weight: 600;
    color: var(--color-ink);
    font-size: 0.98rem;
}
.forecast-conf {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--color-accent);
    background: var(--color-accent-soft);
    padding: 2px 10px;
    border-radius: 12px;
    font-weight: 600;
}
.forecast p {
    margin: 0;
    font-size: 0.92rem;
    color: var(--color-ink-soft);
}

/* --- Closing block --- */
.closing {
    margin: 56px 0;
    padding: 40px 36px;
    background: var(--color-ink);
    color: #f0f0e8;
    border-radius: var(--radius-md);
}
.closing h2 {
    font-family: var(--font-serif);
    font-size: 1.6rem;
    margin: 0 0 16px;
    color: #fff;
    font-weight: 500;
}
.closing p {
    color: #d0d0c8;
    margin: 0 0 16px;
    font-size: 1rem;
    line-height: 1.8;
}
.closing p:last-child { margin-bottom: 0; }
.closing strong { color: var(--color-accent-bright); font-weight: 600; }

/* --- Footer --- */
.footer {
    border-top: 1px solid var(--color-line);
    background: var(--color-surface);
    padding: 48px 0 32px;
    color: var(--color-muted);
    font-size: 0.86rem;
}
.footer-inner {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 24px;
}
.footer p { margin: 0; }
.footer .meta {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.05em;
}

/* --- Utility --- */
.text-mono { font-family: var(--font-mono); }
.text-accent { color: var(--color-accent); }
.text-muted { color: var(--color-muted); }
.text-center { text-align: center; }
.mb-0 { margin-bottom: 0; }

/* --- Mobile --- */
@media (max-width: 700px) {
    .container, .container-narrow { padding: 0 20px; }
    .hero { padding: 56px 0 40px; }
    .layout { padding: 40px 20px 64px; gap: 32px; }
    .hero-meta { gap: 20px; }
    .header-inner { height: 56px; }
    .content > section { padding: 40px 0; }
    .stage { padding: 24px 0; }
    .timeline-row { grid-template-columns: 1fr; gap: 6px; }
    .compare-row { grid-template-columns: 1fr; gap: 12px; padding: 14px 0; }
    .compare-row .truth::before { content: "→ "; }
    .compare-header { display: none; }
    .closing { padding: 28px 22px; margin: 32px 0; }
}

/* --- Print --- */
@media print {
    .site-header, .toc, .footer { display: none; }
    body { background: white; }
    .content > section { padding: 24px 0; page-break-inside: avoid; }
    .closing { background: white; color: black; border: 1px solid #ccc; }
    .closing h2, .closing p, .closing strong { color: black; }
}