:root {
    --paper: #f5f1e8;
    --paper-strong: #fffdfa;
    --paper-soft: rgba(255, 253, 250, 0.88);
    --ink: #16253a;
    --ink-soft: #5b6980;
    --navy: #12324a;
    --navy-deep: #0d2133;
    --bronze: #8c6a39;
    --line: rgba(18, 50, 74, 0.14);
    --line-strong: rgba(18, 50, 74, 0.22);
    --shadow: 0 22px 48px rgba(17, 34, 56, 0.12);
    --shadow-soft: 0 14px 28px rgba(17, 34, 56, 0.08);
    --radius-xl: 28px;
    --radius-lg: 22px;
    --radius-md: 16px;
    --radius-sm: 12px;
    --transition: 0.2s ease;
}

html {
    scroll-behavior: smooth;
}

body.site-body {
    margin: 0;
    color: var(--ink);
    background:
        radial-gradient(circle at top left, rgba(140, 106, 57, 0.18), transparent 30%),
        radial-gradient(circle at 90% 10%, rgba(18, 50, 74, 0.14), transparent 28%),
        linear-gradient(180deg, #f7f3eb 0%, #f1ede3 100%);
    font-family: "Palatino Linotype", "Book Antiqua", "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;
    min-height: 100vh;
}

body.site-body::before,
body.site-body::after {
    position: fixed;
    z-index: 0;
    color: rgba(18, 50, 74, 0.06);
    pointer-events: none;
    white-space: pre;
    font-family: "Cambria Math", "Times New Roman", serif;
}

body.site-body::before {
    content: "f(x)=\\sum a_n x^n";
    top: 28px;
    right: 40px;
    font-size: 1.35rem;
    letter-spacing: 0.08rem;
}

body.site-body::after {
    content: "∫  Σ  π  ∂  ∞";
    bottom: 36px;
    left: 28px;
    font-size: 3rem;
    letter-spacing: 0.35rem;
}

body.theme-dark {
    --paper: #101923;
    --paper-strong: #162230;
    --paper-soft: rgba(22, 34, 48, 0.9);
    --ink: #e8eef6;
    --ink-soft: #a3b2c4;
    --navy: #88a9ce;
    --navy-deep: #e9f2ff;
    --bronze: #d6b98d;
    --line: rgba(136, 169, 206, 0.18);
    --line-strong: rgba(136, 169, 206, 0.28);
    --shadow: 0 22px 48px rgba(0, 0, 0, 0.28);
    --shadow-soft: 0 14px 28px rgba(0, 0, 0, 0.22);
    background:
        radial-gradient(circle at top left, rgba(136, 169, 206, 0.12), transparent 30%),
        radial-gradient(circle at 90% 10%, rgba(214, 185, 141, 0.08), transparent 26%),
        linear-gradient(180deg, #0b1118 0%, #101923 100%);
}

body.theme-dark::before,
body.theme-dark::after {
    color: rgba(233, 242, 255, 0.08);
}

a {
    color: inherit;
}

button,
input,
textarea,
select {
    font: inherit;
}

.site-shell {
    position: relative;
    z-index: 1;
    width: min(1220px, calc(100% - 28px));
    margin: 0 auto;
    padding: 18px 0 44px;
}

.site-header {
    position: sticky;
    top: 14px;
    z-index: 30;
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 18px;
    align-items: center;
    padding: 14px 18px;
    margin-bottom: 24px;
    border: 1px solid var(--line);
    border-radius: 20px;
    background: rgba(255, 253, 250, 0.96);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    box-shadow: var(--shadow-soft);
}

body.theme-dark .site-header {
    background: rgba(16, 25, 35, 0.96);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.brand-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    border-radius: 14px;
    background: linear-gradient(135deg, var(--navy) 0%, #12263b 100%);
    color: #fff;
    font-size: 1.1rem;
    font-weight: 700;
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.14);
}

body.theme-dark .brand-mark {
    color: #0b1118;
    background: linear-gradient(135deg, #dae8f8 0%, #88a9ce 100%);
}

.brand-text {
    display: flex;
    flex-direction: column;
    line-height: 1.08;
}

.brand-text strong {
    font-size: 1rem;
    letter-spacing: 0.08rem;
}

.brand-text small {
    color: var(--ink-soft);
    font-size: 0.72rem;
    letter-spacing: 0.12rem;
    text-transform: uppercase;
}

.header-nav {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 14px;
    flex-wrap: wrap;
}

.header-nav a,
.header-actions a,
.header-actions button,
.page-nav-link,
.text-link {
    color: var(--ink-soft);
    text-decoration: none;
    transition: color var(--transition), transform var(--transition), border-color var(--transition), background var(--transition);
}

.header-nav a:hover,
.page-nav-link:hover,
.text-link:hover {
    color: var(--navy);
}

.header-nav a.is-page-active,
.page-nav-link.is-active {
    color: var(--navy);
    font-weight: 700;
}

.header-actions {
    display: inline-flex;
    align-items: center;
    justify-content: flex-end;
    gap: 10px;
}

.utility-button,
.repo-link,
.filter-chip,
.tag-chip,
.page-nav-link,
.copy-button,
.favorite-toggle,
.sort-chip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-height: 38px;
    padding: 0 14px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.03);
    color: var(--ink-soft);
    cursor: pointer;
}

.utility-button:hover,
.repo-link:hover,
.filter-chip:hover,
.tag-chip:hover,
.copy-button:hover,
.favorite-toggle:hover,
.sort-chip:hover {
    border-color: var(--line-strong);
    color: var(--navy);
    transform: translateY(-1px);
}

.utility-button.is-on,
.filter-chip.is-active,
.tag-chip.is-active,
.sort-chip.is-active {
    background: linear-gradient(135deg, var(--navy) 0%, #173a58 100%);
    color: #fff;
    border-color: transparent;
}

body.theme-dark .utility-button.is-on,
body.theme-dark .filter-chip.is-active,
body.theme-dark .tag-chip.is-active,
body.theme-dark .sort-chip.is-active {
    color: #0b1118;
}

.repo-link {
    text-decoration: none;
}

.page-nav {
    position: sticky;
    top: 96px;
    z-index: 20;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 22px;
    padding: 12px 14px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: var(--paper-soft);
    box-shadow: var(--shadow-soft);
}

.page-nav-link {
    min-height: 34px;
    padding: 0 14px;
    border-radius: 999px;
    border: 1px solid transparent;
}

.page-nav-link.is-active {
    background: rgba(18, 50, 74, 0.08);
    border-color: var(--line);
}

.page-hero,
.page-section,
.workspace-panel,
.portal-card,
.search-results-shell,
.table-wrap,
.step-card,
.subject-block,
.formula-card,
.prompt-card,
.footer-shell,
.empty-state {
    border: 1px solid var(--line);
    background: var(--paper-soft);
    box-shadow: var(--shadow-soft);
}

.page-hero {
    overflow: hidden;
    border-radius: var(--radius-xl);
    padding: 28px;
    margin-bottom: 22px;
    position: relative;
}

.page-hero::after {
    content: "";
    position: absolute;
    inset: 0;
    background:
        linear-gradient(rgba(18, 50, 74, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(18, 50, 74, 0.05) 1px, transparent 1px);
    background-size: 24px 24px;
    -webkit-mask-image: linear-gradient(160deg, rgba(0, 0, 0, 0.78), transparent 84%);
    mask-image: linear-gradient(160deg, rgba(0, 0, 0, 0.78), transparent 84%);
    pointer-events: none;
}

body.theme-dark .page-hero::after {
    background:
        linear-gradient(rgba(233, 242, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(233, 242, 255, 0.05) 1px, transparent 1px);
    background-size: 24px 24px;
}

.hero-grid {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.82fr);
    gap: 22px;
}

.hero-copy h1 {
    margin: 0;
    font-size: clamp(2.25rem, 4vw, 3.9rem);
    line-height: 1.04;
    max-width: 12ch;
}

.eyebrow {
    margin: 0 0 12px;
    color: var(--bronze);
    font-size: 0.78rem;
    letter-spacing: 0.16rem;
    text-transform: uppercase;
}

.hero-summary,
.section-summary,
.panel-note,
.card-summary,
.subject-summary,
.step-body,
.empty-state,
.meta-line {
    color: var(--ink-soft);
    line-height: 1.8;
}

.hero-summary {
    max-width: 62ch;
    margin: 18px 0 0;
    font-size: 1.04rem;
}

.hero-actions,
.hero-tags,
.panel-actions,
.toolbar-row,
.filter-row,
.card-meta,
.footer-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.hero-actions {
    margin-top: 24px;
}

.primary-button,
.secondary-button,
.panel-submit {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 18px;
    border-radius: 999px;
    text-decoration: none;
    border: none;
    cursor: pointer;
}

.primary-button,
.panel-submit {
    background: linear-gradient(135deg, var(--navy) 0%, #173a58 100%);
    color: #fff;
    box-shadow: 0 14px 30px rgba(18, 50, 74, 0.18);
}

body.theme-dark .primary-button,
body.theme-dark .panel-submit {
    color: #0b1118;
}

.secondary-button {
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.03);
}

.metric-grid,
.card-grid,
.portal-grid,
.workspace-grid,
.mini-card-grid,
.step-grid,
.prompt-grid,
.formula-grid,
.subject-grid {
    display: grid;
    gap: 16px;
}

.metric-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    margin-top: 26px;
}

.metric-card {
    padding: 18px;
    border-radius: 18px;
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.04);
}

.metric-card strong {
    display: block;
    font-size: 1.95rem;
    line-height: 1;
    color: var(--navy);
}

.metric-card span {
    display: block;
    margin-top: 8px;
    color: var(--ink-soft);
}

.hero-panel {
    display: grid;
    gap: 14px;
    padding: 22px;
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    background: rgba(255, 253, 250, 0.92);
    box-shadow: var(--shadow-soft);
}

body.theme-dark .hero-panel {
    background: rgba(22, 34, 48, 0.92);
}

.panel-heading strong {
    display: block;
    font-size: 1.15rem;
}

.panel-input,
.search-input,
.panel-textarea {
    width: 100%;
    min-height: 48px;
    padding: 0 16px;
    border-radius: 16px;
    border: 1px solid var(--line);
    background: rgba(255, 255, 255, 0.76);
    color: var(--ink);
    outline: none;
}

body.theme-dark .panel-input,
body.theme-dark .search-input,
body.theme-dark .panel-textarea {
    background: rgba(10, 18, 27, 0.6);
}

.panel-input:focus,
.search-input:focus,
.panel-textarea:focus {
    border-color: var(--navy);
    box-shadow: 0 0 0 4px rgba(18, 50, 74, 0.08);
}

.panel-textarea {
    min-height: 156px;
    padding: 14px 16px;
    resize: vertical;
}

.page-section {
    padding: 24px;
    border-radius: var(--radius-xl);
    margin-bottom: 22px;
}

.section-heading {
    display: flex;
    align-items: end;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 18px;
}

.section-title {
    margin: 0;
    font-size: clamp(1.55rem, 2vw, 2.15rem);
}

.card-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
}

.portal-grid,
.workspace-grid,
.step-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.mini-card-grid,
.prompt-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.formula-grid,
.subject-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.portal-card,
.workspace-panel,
.link-card,
.step-card,
.subject-block,
.formula-card,
.prompt-card {
    position: relative;
    overflow: hidden;
    border-radius: var(--radius-lg);
}

.portal-card,
.workspace-panel,
.step-card,
.subject-block,
.formula-card,
.prompt-card {
    padding: 20px;
}

.link-card {
    display: flex;
    flex-direction: column;
    min-height: 100%;
    padding: 20px;
    transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.link-card::before,
.portal-card::before,
.workspace-panel::before,
.subject-block::before,
.formula-card::before,
.prompt-card::before,
.step-card::before {
    content: "";
    position: absolute;
    inset: 0 auto auto 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--bronze) 0%, var(--navy) 100%);
    opacity: 0.9;
}

.link-card:hover,
.portal-card:hover,
.workspace-panel:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.card-head,
.workspace-head,
.prompt-head {
    display: flex;
    align-items: start;
    justify-content: space-between;
    gap: 10px;
}

.card-kind,
.portal-kind,
.prompt-kind,
.workspace-kind {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--bronze);
    font-size: 0.76rem;
    letter-spacing: 0.12rem;
    text-transform: uppercase;
}

.favorite-toggle {
    width: 38px;
    padding: 0;
    flex: 0 0 38px;
}

.favorite-toggle.is-favorite {
    background: linear-gradient(135deg, #d69a38 0%, #b57211 100%);
    color: #fff;
    border-color: transparent;
}

.card-link {
    display: block;
    margin-top: 14px;
    text-decoration: none;
}

.card-title,
.portal-title,
.prompt-title,
.subject-title {
    margin: 0;
    font-size: 1.14rem;
    line-height: 1.32;
}

.card-summary {
    margin: 12px 0 0;
}

.card-meta {
    margin-top: auto;
    padding-top: 14px;
}

.meta-pill,
.official-pill,
.tag-badge {
    display: inline-flex;
    align-items: center;
    min-height: 28px;
    padding: 0 10px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.04);
    font-size: 0.82rem;
    color: var(--ink-soft);
}

.official-pill {
    color: var(--navy);
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 14px;
}

.search-toolbar {
    display: grid;
    gap: 12px;
}

.search-results-shell {
    padding: 18px;
    border-radius: var(--radius-lg);
}

.search-result-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 14px;
}

.workspace-grid {
    align-items: start;
}

.workspace-panel {
    min-height: 240px;
}

.workspace-panel[draggable="true"] {
    cursor: grab;
}

.workspace-panel.is-dragging {
    opacity: 0.45;
}

.drag-handle {
    color: var(--ink-soft);
    font-size: 0.95rem;
}

.empty-hint {
    color: var(--ink-soft);
    line-height: 1.8;
    margin-top: 14px;
}

.portal-card {
    text-decoration: none;
}

.portal-card p,
.workspace-panel p,
.prompt-card p {
    margin: 10px 0 0;
    color: var(--ink-soft);
    line-height: 1.8;
}

.table-wrap {
    overflow: auto;
    border-radius: var(--radius-lg);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 900px;
}

.data-table th,
.data-table td {
    padding: 14px 16px;
    border-bottom: 1px solid var(--line);
    text-align: left;
    vertical-align: top;
}

.data-table thead th {
    position: sticky;
    top: 0;
    background: var(--paper-strong);
    color: var(--navy);
    z-index: 1;
}

body.theme-dark .data-table thead th {
    background: var(--paper);
}

.compare-badge {
    display: inline-flex;
    align-items: center;
    min-height: 28px;
    padding: 0 10px;
    border-radius: 999px;
    background: rgba(18, 50, 74, 0.08);
    color: var(--navy);
    font-size: 0.82rem;
}

.step-grid {
    margin-top: 18px;
}

.step-index {
    color: var(--bronze);
    font-weight: 700;
    letter-spacing: 0.08rem;
    text-transform: uppercase;
}

.step-card h3 {
    margin: 12px 0 10px;
    font-size: 1.1rem;
}

.subject-toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 16px;
}

.subject-bookshelf {
    display: grid;
    gap: 12px;
    margin-top: 16px;
}

.book-list {
    display: grid;
    gap: 10px;
    padding: 0;
    margin: 0;
    list-style: none;
}

.book-card {
    padding: 14px 16px;
    border-radius: 14px;
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.04);
}

.book-card strong {
    display: block;
    font-size: 1rem;
}

.book-card span {
    display: block;
    margin-top: 6px;
    color: var(--ink-soft);
}

.mini-card-grid .link-card,
.mini-card-grid .portal-card,
.mini-card-grid .formula-card {
    padding: 16px;
}

.formula-card h3,
.prompt-card h3 {
    margin: 0;
    font-size: 1.06rem;
}

.formula-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 14px;
}

.formula-table td,
.formula-table th {
    padding: 10px 0;
    border-bottom: 1px solid var(--line);
    vertical-align: top;
}

.formula-command {
    font-family: "Cascadia Code", Consolas, monospace;
    font-size: 0.94rem;
}

.formula-symbol {
    font-size: 1.12rem;
    color: var(--navy);
}

.code-snippet {
    padding: 14px;
    border-radius: 14px;
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.06);
    overflow: auto;
    white-space: pre;
    font-family: "Cascadia Code", Consolas, monospace;
    font-size: 0.9rem;
    line-height: 1.7;
}

.result-box {
    width: 100%;
    min-height: 160px;
    margin-top: 14px;
    padding: 16px;
    border-radius: 16px;
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.04);
    white-space: pre-wrap;
    line-height: 1.75;
}

.footer-shell {
    margin-top: 26px;
    padding: 20px 22px;
    border-radius: 20px;
}

.footer-shell p {
    margin: 0;
    color: var(--ink-soft);
    line-height: 1.8;
}

.footer-shell .footer-row {
    margin-top: 10px;
}

.floating-top {
    position: fixed;
    right: 18px;
    bottom: 18px;
    z-index: 40;
    width: 46px;
    height: 46px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: rgba(255, 253, 250, 0.92);
    color: var(--navy);
    box-shadow: var(--shadow-soft);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition), transform var(--transition);
}

body.theme-dark .floating-top {
    background: rgba(16, 25, 35, 0.92);
}

.floating-top.is-visible {
    opacity: 1;
    pointer-events: auto;
}

.status-message {
    padding: 14px 16px;
    border-radius: 16px;
    border: 1px solid var(--line);
    background: rgba(18, 50, 74, 0.04);
    color: var(--ink-soft);
}

.loading-shell {
    padding: 90px 20px;
    text-align: center;
    color: var(--ink-soft);
}

@media (max-width: 1180px) {
    .card-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .portal-grid,
    .workspace-grid,
    .step-grid,
    .subject-grid,
    .formula-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 920px) {
    .site-header {
        grid-template-columns: 1fr;
        justify-items: stretch;
    }

    .header-nav {
        justify-content: flex-start;
        overflow-x: auto;
        flex-wrap: nowrap;
        padding-bottom: 4px;
    }

    .header-actions {
        justify-content: flex-start;
        flex-wrap: wrap;
    }

    .hero-grid {
        grid-template-columns: 1fr;
    }

    .metric-grid,
    .card-grid,
    .portal-grid,
    .workspace-grid,
    .mini-card-grid,
    .prompt-grid,
    .step-grid,
    .subject-grid,
    .formula-grid {
        grid-template-columns: 1fr;
    }

    .section-heading,
    .search-result-head {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 640px) {
    .site-shell {
        width: min(100% - 18px, 100%);
        padding-top: 12px;
    }

    .site-header {
        top: 8px;
        padding: 12px;
    }

    .page-nav {
        top: 84px;
    }

    .page-hero,
    .page-section,
    .workspace-panel,
    .portal-card,
    .step-card,
    .subject-block,
    .formula-card,
    .prompt-card {
        padding: 18px;
    }

    .hero-copy h1 {
        max-width: 100%;
    }

    body.site-body::before,
    body.site-body::after {
        display: none;
    }
}