/* ═══════════════════════════════════════════════════
   Swiss Typographic Design System
   Bricolage Grotesque + DM Sans + DM Mono
   ═══════════════════════════════════════════════════ */

:root {
    --bg: #F7F6F3;
    --surface: #FFFFFF;
    --surface-alt: #F0EFEC;
    --ink: #0D0D0D;
    --ink-muted: #2A2A2A;
    --ink-soft: #6B6B6B;
    --line: #D1D0CC;
    --line-soft: #E3E2DE;
    --accent: #D64045;
    --accent-soft: rgba(214, 64, 69, 0.08);
    --danger: #D64045;

    --font-display: 'Source Serif 4', Georgia, serif;
    --font-body: 'IBM Plex Sans', 'Segoe UI', sans-serif;
    --font-mono: 'IBM Plex Mono', 'Courier New', monospace;

    --max-width: 1200px;
    --radius-lg: 3px;
    --radius-md: 2px;
    --radius-sm: 2px;
    --space-section: clamp(5rem, 10vw, 7rem);
    --space-stack: 1.5rem;
    --space-card: 1rem;
    --grid-line: 1px solid var(--line);

    --shadow-soft: none;
    --shadow-card: none;
}

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    color-scheme: light;
}

body {
    font-family: var(--font-body);
    color: var(--ink);
    line-height: 1.65;
    background: var(--bg);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

a {
    color: inherit;
    text-decoration: none;
}

img,
svg {
    display: block;
    max-width: 100%;
}

[hidden] {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* ═══════════════════════════════════════════════════
   Navigation — thin horizontal rule, minimal chrome
   ═══════════════════════════════════════════════════ */
.site-nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(247, 246, 243, 0.92);
    backdrop-filter: blur(12px);
    border-bottom: 2px solid var(--ink);
}

.nav-shell {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0.9rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.brand {
    font-family: var(--font-display);
    font-size: 0.82rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    font-weight: 700;
    color: var(--ink);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    flex-direction: column;
    gap: 5px;
}

.nav-toggle-bar {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--ink);
    border-radius: 0;
    transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-open .nav-toggle-bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-open .nav-toggle-bar:nth-child(2) {
    opacity: 0;
}

.nav-open .nav-toggle-bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

.nav-links {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 0.25rem;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.nav-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-body);
    font-size: 0.78rem;
    font-weight: 500;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-soft);
    padding: 0.4rem 0.7rem;
    min-height: 2.2rem;
    border: 1px solid transparent;
    transition: color 0.15s ease;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--ink);
}

.nav-links a.active {
    border-bottom: 2px solid var(--accent);
    padding-bottom: calc(0.4rem - 2px);
}

/* ═══════════════════════════════════════════════════
   Layout — strict grid, generous whitespace
   ═══════════════════════════════════════════════════ */
main {
    overflow: hidden;
}

.content-section {
    padding: var(--space-section) 2rem;
}

.section-tone {
    background: var(--surface);
    border-top: var(--grid-line);
}

.section-shell {
    max-width: var(--max-width);
    margin: 0 auto;
    display: grid;
    gap: var(--space-stack);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    gap: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--ink);
}

.section-header-tight {
    margin-bottom: 0;
    padding-bottom: 0.8rem;
}

.section-heading {
    display: grid;
    gap: 0.5rem;
}

.section-subtitle {
    color: var(--ink-soft);
    max-width: 60ch;
    font-size: 0.92rem;
    line-height: 1.55;
}

.section-header-meta {
    display: grid;
    justify-items: end;
    gap: 0.5rem;
    text-align: right;
    flex-shrink: 0;
}

.section-updated {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--ink-soft);
    letter-spacing: 0.02em;
}

.section-cta {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--ink);
    background: transparent;
    color: var(--ink);
    font-family: var(--font-body);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    min-height: 2rem;
    padding: 0.2rem 0.8rem;
    transition: all 0.15s ease;
}

.section-cta:hover {
    background: var(--ink);
    color: var(--bg);
}

.section-label-row {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.section-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 2rem;
    min-height: 1.4rem;
    padding: 0 0.38rem;
    border: 1px solid var(--line);
    color: var(--accent);
    background: var(--accent-soft);
    font-family: var(--font-mono);
    font-size: 0.64rem;
    font-weight: 500;
    letter-spacing: 0.06em;
}

.section-divider {
    padding-top: 0.7rem;
}

.section-label {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.16em;
    color: var(--accent);
    font-weight: 500;
}

/* ═══════════════════════════════════════════════════
   Typography — dramatic scale, Bricolage Grotesque
   ═══════════════════════════════════════════════════ */
h1,
h2,
h3,
h4 {
    font-family: var(--font-display);
    line-height: 1.1;
    color: var(--ink);
    font-weight: 700;
    letter-spacing: -0.03em;
}

h1 {
    font-size: clamp(2.8rem, 6vw, 5rem);
    font-weight: 800;
    letter-spacing: -0.04em;
    line-height: 1.0;
}

h2 {
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 700;
    letter-spacing: -0.03em;
}

h3 {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

p {
    color: var(--ink-muted);
}

/* ═══════════════════════════════════════════════════
   Hero — asymmetric, oversized type
   ═══════════════════════════════════════════════════ */
.hero {
    padding: 5rem 2rem 6rem;
    border-bottom: 2px solid var(--ink);
}

.hero-shell {
    max-width: var(--max-width);
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: 3rem;
    align-items: center;
}

.eyebrow {
    font-family: var(--font-mono);
    font-size: 0.76rem;
    text-transform: uppercase;
    letter-spacing: 0.14em;
    color: var(--accent);
    margin-bottom: 1rem;
}

.hero-lead {
    margin-top: 1.4rem;
    font-size: 1.05rem;
    max-width: 55ch;
    line-height: 1.6;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    margin-top: 2.2rem;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    padding: 0.7rem 1.4rem;
    border: 2px solid transparent;
    transition: all 0.15s ease;
}

.button-primary {
    background: var(--ink);
    color: var(--bg);
    border-color: var(--ink);
}

.button-primary:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: #FFFFFF;
}

.button-secondary {
    border-color: var(--ink);
    background: transparent;
    color: var(--ink);
}

.button-secondary:hover {
    background: var(--ink);
    color: var(--bg);
}

.hero-facts {
    margin-top: 1.4rem;
    list-style: none;
    display: grid;
    gap: 0.45rem;
}

.hero-facts li {
    font-size: 0.88rem;
    color: var(--ink-soft);
}

.hero-visual {
    display: grid;
    gap: 0.9rem;
}

.graph-card {
    background: var(--surface);
    border: 2px solid var(--ink);
    padding: 1rem;
}

#nav-graph-container {
    width: 100%;
    max-width: 440px;
    margin: 0 auto;
}

.nav-graph-svg {
    width: 100%;
    height: auto;
}

.nav-graph-svg .nav-edge {
    stroke: var(--ink-soft);
    stroke-width: 1;
    opacity: 0.25;
}

.nav-graph-svg .nav-vertex-bg {
    fill: var(--surface);
    stroke: var(--ink);
    stroke-width: 1.5;
}

.nav-graph-svg .nav-axis-label {
    font-size: 10px;
    font-family: var(--font-mono);
    fill: var(--ink-soft);
    font-weight: 500;
}


.graph-placeholder {
    font-size: 0.84rem;
    color: var(--ink-soft);
}

/* ═══════════════════════════════════════════════════
   Cards & Grids — sharp edges, structural borders
   ═══════════════════════════════════════════════════ */
.two-column {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-card);
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1rem;
}

.feature-card,
.interest-card,
.course-card,
.resource-column,
.document-item,
.panel {
    background: var(--surface);
    border: 1px solid var(--line);
    border-top: 3px solid var(--ink);
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    height: 100%;
}

.feature-card,
.interest-card,
.course-card,
.resource-column,
.document-item,
.panel {
    padding: 1.4rem 1.2rem;
}

.feature-card p,
.interest-card p,
.course-card p {
    margin-top: 0.5rem;
    font-size: 0.92rem;
    line-height: 1.6;
}

.materials-strip {
    margin-top: 1.5rem;
    padding: 1.2rem;
    border: 1px dashed var(--line);
    background: var(--surface-alt);
}

.materials-strip h3 {
    font-size: 1.06rem;
}

.materials-strip ul {
    margin-top: 0.7rem;
    list-style: none;
    display: grid;
    gap: 0.42rem;
}

.materials-strip a {
    color: var(--accent);
    font-weight: 500;
}

.materials-strip a:hover,
.text-link:hover,
.resource-column a:hover,
.document-action:hover {
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 3px;
}

.interest-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--space-card);
    align-items: stretch;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: var(--space-card);
    align-items: stretch;
}

.course-card header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 0.6rem;
    margin-bottom: 0.35rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--line-soft);
}

.course-code {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    font-weight: 500;
    color: var(--accent);
}

.course-term {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--ink-soft);
}

.course-meta {
    margin-top: 0.8rem;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--ink-soft);
}

.text-link {
    margin-top: 0.9rem;
    display: inline-block;
    color: var(--accent);
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.course-card .text-link {
    margin-top: auto;
    padding-top: 0.5rem;
}

.resource-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: var(--space-card);
    align-items: stretch;
}

.resource-column h3 {
    font-size: 1.06rem;
    margin-bottom: 0.7rem;
}

.resource-column ul {
    list-style: none;
    display: grid;
    gap: 0.45rem;
}

.resource-column a {
    color: var(--ink-muted);
    font-size: 0.93rem;
}

/* ═══════════════════════════════════════════════════
   Dossier — login panel
   ═══════════════════════════════════════════════════ */
.dossier-intro {
    max-width: 80ch;
    margin-bottom: 1.2rem;
}

.dossier-panel {
    background: var(--surface);
    border: 1px solid var(--line);
    border-top: 3px solid var(--ink);
    padding: 1.5rem;
}

.login-box {
    max-width: 560px;
    display: grid;
    gap: 0.8rem;
}

.login-title {
    color: var(--ink);
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.1rem;
}

.login-box form {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.login-box input {
    width: 100%;
    min-width: 220px;
    border: 2px solid var(--line);
    padding: 0.65rem 0.85rem;
    font-family: var(--font-mono);
    font-size: 0.88rem;
    color: var(--ink);
    background: var(--bg);
    transition: border-color 0.15s ease;
}

.login-box input:focus {
    outline: none;
    border-color: var(--ink);
}

.login-box button,
.logout-btn {
    border: 2px solid var(--ink);
    background: var(--ink);
    color: var(--bg);
    font-family: var(--font-body);
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    padding: 0.65rem 1.1rem;
    cursor: pointer;
    transition: all 0.15s ease;
}

.login-box button:hover,
.logout-btn:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: #FFFFFF;
}

.auth-message {
    min-height: 1.25rem;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--ink-soft);
}

.auth-message.error {
    color: var(--danger);
}

.auth-message.success {
    color: var(--accent);
}

.protected-content {
    display: grid;
    gap: 1rem;
}

.protected-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    gap: 1rem;
}

.protected-header h3 {
    font-size: 1.4rem;
}

.documents-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-card);
    align-items: stretch;
}

.document-item {
    display: grid;
    gap: 0.55rem;
}

.document-item h4 {
    font-size: 1.04rem;
}

.document-item p {
    font-size: 0.89rem;
}

.document-action {
    width: fit-content;
    margin-top: 0.15rem;
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    color: var(--accent);
}

.document-item:not(.is-available) .document-action {
    color: var(--ink-soft);
    cursor: not-allowed;
    pointer-events: none;
}

.document-item.is-available {
    border-color: var(--accent);
    border-top-color: var(--accent);
}

.protected-file-item {
    display: flex;
    align-items: baseline;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.protected-file-download {
    font-family: var(--font-body);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--accent);
    border: 1.5px solid var(--accent);
    padding: 0.15rem 0.55rem;
    transition: all 0.15s ease;
    white-space: nowrap;
}

.protected-file-download:hover {
    background: var(--accent);
    color: #ffffff;
    text-decoration: none;
}

.protected-file-meta {
    margin-left: 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--ink-soft);
    white-space: nowrap;
}

/* ═══════════════════════════════════════════════════
   Course page — DS1000
   ═══════════════════════════════════════════════════ */
.course-page {
    padding: clamp(3.8rem, 7vw, 5rem) 2rem var(--space-section);
}

.course-shell {
    max-width: var(--max-width);
    margin: 0 auto;
    display: grid;
    gap: 1.5rem;
}

.breadcrumb {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--ink-soft);
    letter-spacing: 0.02em;
}

.breadcrumb:hover {
    color: var(--ink);
}

.quick-links-mobile {
    display: none;
}

.course-intro {
    display: grid;
    gap: 0.8rem;
    background: var(--surface);
    border: 1px solid var(--line);
    border-top: 3px solid var(--ink);
    padding: 1.5rem;
}

.course-intro .section-header {
    border-bottom: none;
    padding-bottom: 0;
}

.course-intro .section-label {
    margin: 0;
}

.course-intro p {
    max-width: 78ch;
}

.course-updates .update-strip {
    border-style: dashed;
    background: var(--surface-alt);
}

.update-list {
    margin-top: 0.65rem;
    padding-left: 1.1rem;
    display: grid;
    gap: 0.42rem;
}

.update-list li {
    color: var(--ink-muted);
    font-size: 0.91rem;
}

.course-meta-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--space-card);
}

.panel h3 {
    font-size: 1.06rem;
}

.panel p,
.panel li {
    font-size: 0.92rem;
    color: var(--ink-muted);
}

.panel ul {
    margin-top: 0.7rem;
    list-style: none;
    display: grid;
    gap: 0.45rem;
}

.material-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
}

.material-card h3 {
    font-size: 1.08rem;
}

.material-list {
    margin-top: 0.75rem;
    list-style: none;
    display: grid;
    gap: 0.45rem;
}

.material-list a,
.material-note a {
    color: var(--accent);
    font-size: 0.9rem;
}

.pdf-updated-meta {
    display: inline-block;
    margin-left: 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--ink-soft);
    white-space: nowrap;
}

.material-note {
    margin-top: 0.75rem;
    font-size: 0.88rem;
    color: var(--ink-soft);
}

.placeholder-text {
    margin-top: 0.75rem;
    font-size: 0.88rem;
    color: var(--ink-soft);
    font-style: italic;
}

.core-materials {
    display: grid;
    gap: var(--space-stack);
}

.weekly-materials {
    display: grid;
    gap: var(--space-stack);
}

.week-list {
    display: grid;
    gap: var(--space-card);
}

.assignment-list {
    display: grid;
    gap: var(--space-card);
    margin-top: 0.75rem;
}

.week-item {
    background: var(--surface);
    border: 1px solid var(--line);
    border-left: 3px solid var(--ink);
    overflow: hidden;
}

.week-item summary {
    list-style: none;
    cursor: pointer;
    padding: 1rem 1.2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    border-bottom: 1px solid transparent;
    transition: background 0.1s ease;
}

.week-item summary::-webkit-details-marker {
    display: none;
}

.week-item[open] summary {
    border-bottom-color: var(--line);
    background: var(--surface-alt);
}

.week-title {
    font-family: var(--font-display);
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--ink);
    letter-spacing: -0.01em;
}

.week-updated {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--ink-soft);
    white-space: nowrap;
    margin-left: auto;
}

.week-status {
    flex-shrink: 0;
    font-family: var(--font-mono);
    font-size: 0.68rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 500;
    color: var(--accent);
    background: var(--accent-soft);
    padding: 0.22rem 0.56rem;
}

.week-status-soon {
    color: var(--ink-soft);
    background: var(--surface-alt);
}

.week-content {
    padding: 1rem 1.2rem 1.2rem;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-card);
    align-items: stretch;
}

.week-block {
    border: 1px solid var(--line-soft);
    padding: 0.85rem;
    background: var(--bg);
    height: 100%;
}

.week-block h3 {
    font-size: 1rem;
}

.week-block .placeholder-text {
    margin-top: 0.5rem;
}

.autofile-link.is-unavailable {
    color: var(--ink-soft);
    text-decoration: line-through;
    cursor: not-allowed;
    pointer-events: none;
}

.autofile-link:not([href]),
.autofile-link[aria-disabled="true"] {
    color: var(--ink-soft);
    text-decoration: line-through;
    cursor: not-allowed;
    pointer-events: none;
    opacity: 0.9;
}

.autofile-link:not([href])::before,
.autofile-link[aria-disabled="true"]::before {
    content: '\2717  ';
    font-weight: 600;
}

.autofile-link.is-available {
    pointer-events: auto;
}

.inactive-file-link {
    color: var(--ink-soft) !important;
    text-decoration: line-through;
    cursor: not-allowed;
    pointer-events: none;
    opacity: 0.9;
}

.inactive-file-link::before {
    content: '\2717  ';
    font-weight: 600;
}

/* ═══════════════════════════════════════════════════
   Footer — minimal, structural
   ═══════════════════════════════════════════════════ */
.site-footer {
    border-top: 2px solid var(--ink);
    background: var(--bg);
}

.footer-shell {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1.4rem 2rem 2rem;
}

.site-footer p {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--ink-soft);
    letter-spacing: 0.04em;
}

/* ═══════════════════════════════════════════════════
   Motion — precise, mechanical reveals
   ═══════════════════════════════════════════════════ */
.reveal {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1),
                transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* ═══════════════════════════════════════════════════
   Pace Tracker
   ═══════════════════════════════════════════════════ */
.pace-page {
    padding: clamp(3.8rem, 7vw, 5rem) 2rem var(--space-section);
}

.pace-shell {
    max-width: 600px;
    margin: 0 auto;
    display: grid;
    gap: 1.5rem;
}

.pace-intro {
    display: grid;
    gap: 0.5rem;
}

.pace-intro p {
    font-size: 0.92rem;
    max-width: 50ch;
}

.pace-vote-group {
    display: grid;
    gap: 0.75rem;
}

.pace-vote-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    width: 100%;
    min-height: 3.6rem;
    padding: 0.9rem 1.2rem;
    border: 2px solid var(--line);
    background: var(--surface);
    color: var(--ink);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    cursor: pointer;
    transition: border-color 0.15s ease, background 0.15s ease, color 0.15s ease;
}

.pace-vote-btn:hover {
    border-color: var(--ink);
}

.pace-vote-btn.is-selected {
    border-color: var(--accent);
    background: var(--accent);
    color: #FFFFFF;
}

.pace-vote-btn:disabled {
    opacity: 0.6;
    cursor: wait;
}

.pace-vote-icon {
    font-size: 1.3rem;
    line-height: 1;
}

.pace-vote-confirm {
    min-height: 1.5rem;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--ink-soft);
}

.pace-qr-section {
    display: grid;
    gap: 0.6rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--line-soft);
}

.pace-qr-section p {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--ink-soft);
}

.pace-qr-canvas {
    width: 140px;
    height: 140px;
    border: 1px solid var(--line);
    background: #FFFFFF;
    padding: 8px;
}

.pace-divider {
    border: none;
    border-top: 2px solid var(--ink);
    margin: 0.5rem 0;
}

/* ── Instructor dashboard ── */
.pace-dashboard {
    display: grid;
    gap: 1rem;
}

.pace-dashboard-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 1rem;
}

.pace-dashboard-header h3 {
    font-size: 1.25rem;
}

.pace-total {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--ink-soft);
}

.pace-bar-chart {
    display: grid;
    gap: 0.6rem;
}

.pace-bar-row {
    display: grid;
    grid-template-columns: 100px 1fr 50px;
    align-items: center;
    gap: 0.75rem;
}

.pace-bar-label {
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--ink);
}

.pace-bar-track {
    height: 28px;
    background: var(--surface-alt);
    border: 1px solid var(--line-soft);
    position: relative;
    overflow: hidden;
}

.pace-bar-fill {
    height: 100%;
    transition: width 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    min-width: 0;
}

.pace-bar-fill-fast {
    background: var(--accent);
}

.pace-bar-fill-good {
    background: #3b8132;
}

.pace-bar-fill-slow {
    background: #2e86ab;
}

[data-theme="dark"] .pace-bar-fill-good {
    background: #81C784;
}

[data-theme="dark"] .pace-bar-fill-slow {
    background: #64B5F6;
}

.pace-bar-value {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--ink-muted);
    text-align: right;
}

.pace-reset-btn {
    justify-self: start;
    border: 2px solid var(--line);
    background: transparent;
    color: var(--ink-soft);
    font-family: var(--font-body);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: all 0.15s ease;
}

.pace-reset-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.pace-session-meta {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--ink-soft);
}

/* ═══════════════════════════════════════════════════
   Responsive
   ═══════════════════════════════════════════════════ */
@media (max-width: 1024px) {
    .hero-shell {
        grid-template-columns: 1fr;
    }

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

    .resource-grid,
    .course-meta-grid,
    .material-grid {
        grid-template-columns: 1fr;
    }

    .week-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 760px) {
    .nav-shell {
        flex-wrap: wrap;
        padding: 0.75rem 1.25rem;
        gap: 0.75rem;
    }

    .nav-toggle {
        display: flex;
        order: 2;
        min-width: 2.75rem;
        min-height: 2.75rem;
        align-items: center;
        justify-content: center;
    }

    .brand {
        order: 1;
        flex: 1;
        min-width: 0;
    }

    .theme-toggle {
        order: 3;
    }

    .nav-shell nav {
        display: none;
        width: 100%;
        padding-top: 0.75rem;
        order: 4;
        border-top: 1px solid var(--line);
    }

    .nav-open nav {
        display: block;
    }

    .nav-links {
        flex-direction: column;
        gap: 0;
        width: 100%;
    }

    .nav-links a {
        display: flex;
        align-items: center;
        width: 100%;
        padding: 0.75rem 0.5rem;
        min-height: 2.9rem;
        font-size: 0.82rem;
        border-bottom: 1px solid var(--line-soft);
    }

    .nav-links a.active {
        border-bottom-color: var(--accent);
        padding-bottom: 0.75rem;
    }

    .quick-links-mobile {
        display: flex;
        gap: 0.4rem;
        overflow-x: auto;
        padding: 0.5rem 0 0.25rem;
        margin-top: -0.35rem;
        position: sticky;
        top: 4rem;
        z-index: 85;
        background: rgba(247, 246, 243, 0.96);
        border-bottom: 1px solid var(--line);
        backdrop-filter: blur(8px);
    }

    .quick-links-mobile a {
        white-space: nowrap;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        min-height: 2.2rem;
        padding: 0.15rem 0.7rem;
        font-family: var(--font-mono);
        font-size: 0.72rem;
        letter-spacing: 0.04em;
        border: 1px solid var(--line);
        color: var(--ink-muted);
        background: var(--surface);
    }

    .hero {
        padding: 3rem 1.25rem 3.5rem;
    }

    .content-section {
        padding: 3.5rem 1.25rem;
    }

    .course-page {
        padding: 2.5rem 1.25rem 3.5rem;
    }

    h1 {
        font-size: 2.2rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    h3 {
        font-size: 1.1rem;
    }

    .hero-lead {
        font-size: 0.95rem;
    }

    .hero-actions {
        margin-top: 1.6rem;
    }

    .hero-visual {
        display: none;
    }

    .two-column,
    .card-grid,
    .interest-grid,
    .course-grid,
    .documents-grid {
        grid-template-columns: 1fr;
    }

    .feature-card,
    .interest-card,
    .course-card,
    .resource-column,
    .document-item,
    .panel {
        padding: 1.1rem 1rem;
    }

    .login-box form {
        flex-direction: column;
        align-items: stretch;
    }

    .login-box input {
        min-width: 0;
        font-size: 1rem;
        padding: 0.75rem 0.85rem;
    }

    .login-box button,
    .logout-btn {
        padding: 0.75rem 1rem;
        font-size: 0.82rem;
    }

    .protected-file-item {
        flex-direction: column;
        gap: 0.3rem;
        padding: 0.5rem 0;
        border-bottom: 1px solid var(--line-soft);
    }

    .protected-file-item:last-child {
        border-bottom: none;
    }

    .protected-file-download {
        align-self: flex-start;
    }

    .protected-file-meta {
        margin-left: 0;
    }

    .week-item summary {
        padding: 0.85rem 1rem;
        flex-wrap: wrap;
        gap: 0.4rem;
    }

    .week-title {
        flex: 1 1 100%;
        font-size: 0.98rem;
    }

    .week-updated {
        margin-left: 0;
    }

    .week-content {
        padding: 0.75rem;
        gap: 0.6rem;
    }

    .week-block {
        padding: 0.7rem;
    }

    .material-list a,
    .material-note a {
        font-size: 0.88rem;
        display: inline-block;
        padding: 0.15rem 0;
    }

    .assignment-content {
        grid-template-columns: 1fr;
    }

    .course-intro {
        padding: 1.2rem;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .section-header-meta {
        width: 100%;
        justify-items: start;
        text-align: left;
    }

    .footer-shell {
        padding: 1.2rem 1.25rem;
    }

    .dossier-panel {
        padding: 1.1rem;
    }

    .button {
        padding: 0.7rem 1.1rem;
        font-size: 0.78rem;
    }

    .pace-page {
        padding: 2.5rem 1.25rem 3.5rem;
    }

    .pace-bar-row {
        grid-template-columns: 80px 1fr 45px;
        gap: 0.5rem;
    }

    .pace-bar-label {
        font-size: 0.8rem;
    }
}

@media (max-width: 400px) {
    .nav-shell {
        padding: 0.7rem 0.9rem;
    }

    .hero {
        padding: 2rem 0.9rem 2.5rem;
    }

    .content-section {
        padding: 2.5rem 0.9rem;
    }

    .course-page {
        padding: 2rem 0.9rem 3rem;
    }

    h1 {
        font-size: 1.8rem;
    }

    .brand {
        font-size: 0.75rem;
    }

    .pace-page {
        padding: 2rem 0.9rem 3rem;
    }
}

@media (hover: none) {
    .button-primary:hover {
        background: var(--ink);
        border-color: var(--ink);
        color: var(--bg);
    }

    .login-box button:hover,
    .logout-btn:hover {
        background: var(--ink);
        border-color: var(--ink);
    }

    .button-primary:active {
        opacity: 0.85;
    }

    .login-box button:active,
    .logout-btn:active {
        opacity: 0.85;
    }

    .nav-links a:active {
        color: var(--accent);
    }

    .week-item summary:active {
        background: var(--surface-alt);
    }
}

@media print {
    .site-nav,
    .site-footer {
        display: none;
    }

    .login-box {
        display: none;
    }

    body {
        background: #ffffff;
    }

    .content-section,
    .hero,
    .course-page {
        padding: 1.5rem 0;
    }
}

/* ═══════════════════════════════════════════════════
   Theme toggle
   ═══════════════════════════════════════════════════ */
.theme-toggle {
    background: none;
    border: 2px solid var(--ink);
    cursor: pointer;
    padding: 0.35rem 0.45rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--ink);
    transition: all 0.15s ease;
    flex-shrink: 0;
}

.theme-toggle:hover {
    background: var(--ink);
    color: var(--bg);
}

a:focus-visible,
button:focus-visible,
summary:focus-visible,
input:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.theme-toggle svg {
    width: 15px;
    height: 15px;
    display: block;
}

.theme-toggle .icon-moon { display: block; }
.theme-toggle .icon-sun { display: none; }

[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun { display: block; }

/* ═══════════════════════════════════════════════════
   Dark mode — true black, high contrast
   ═══════════════════════════════════════════════════ */
[data-theme="dark"] {
    --bg: #0A0A0A;
    --surface: #141414;
    --surface-alt: #1A1A1A;
    --ink: #F0F0F0;
    --ink-muted: #C8C8C8;
    --ink-soft: #888888;
    --line: #333333;
    --line-soft: #262626;
    --accent: #EF6461;
    --accent-soft: rgba(239, 100, 97, 0.12);
    --danger: #EF6461;
    --shadow-soft: none;
    --shadow-card: none;
    color-scheme: dark;
}

[data-theme="dark"] body {
    background: var(--bg);
}

[data-theme="dark"] .site-nav {
    background: rgba(10, 10, 10, 0.94);
    border-bottom-color: var(--ink);
}

[data-theme="dark"] .section-tone {
    background: var(--surface);
    border-top-color: var(--line);
}

[data-theme="dark"] .section-header {
    border-bottom-color: var(--ink);
}

[data-theme="dark"] .section-cta {
    border-color: var(--ink);
    background: transparent;
    color: var(--ink);
}

[data-theme="dark"] .section-cta:hover {
    background: var(--ink);
    color: var(--bg);
}

[data-theme="dark"] .section-icon {
    border-color: var(--line);
    color: var(--accent);
    background: var(--accent-soft);
}

[data-theme="dark"] .dossier-panel {
    background: var(--surface);
    border-color: var(--line);
    border-top-color: var(--ink);
}

[data-theme="dark"] .login-box input {
    background: var(--bg);
    color: var(--ink);
    border-color: var(--line);
}

[data-theme="dark"] .login-box input:focus {
    border-color: var(--ink);
}

[data-theme="dark"] .week-item[open] summary {
    background: var(--surface-alt);
}

[data-theme="dark"] .week-block {
    background: var(--bg);
}

[data-theme="dark"] .site-footer {
    background: var(--bg);
    border-top-color: var(--ink);
}

[data-theme="dark"] .course-updates .update-strip {
    background: var(--surface-alt);
}

[data-theme="dark"] .nav-graph-svg .nav-edge {
    stroke: var(--ink-soft);
    opacity: 0.3;
}

[data-theme="dark"] .nav-graph-svg .nav-vertex-bg {
    fill: var(--surface);
    stroke: var(--ink);
    stroke-width: 1.5;
}

[data-theme="dark"] .nav-graph-svg .nav-scatter-dot {
    opacity: 1;
    filter: url(#glow);
}

[data-theme="dark"] {
    --graph-c1: #64B5F6;
    --graph-c2: #F06292;
    --graph-c3: #FFB74D;
    --graph-c4: #81C784;
    --graph-c5: #BA68C8;
    --graph-c6: #FF8A65;
}

[data-theme="dark"] .nav-toggle-bar {
    background: var(--ink);
}

[data-theme="dark"] .theme-toggle {
    border-color: var(--ink);
    color: var(--ink);
    background: transparent;
}

[data-theme="dark"] .theme-toggle:hover {
    background: var(--ink);
    color: var(--bg);
}

[data-theme="dark"] .button-primary {
    background: var(--ink);
    color: var(--bg);
    border-color: var(--ink);
}

[data-theme="dark"] .button-primary:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: #FFFFFF;
}

[data-theme="dark"] .button-secondary {
    background: transparent;
    color: var(--ink);
    border-color: var(--ink);
}

[data-theme="dark"] .button-secondary:hover {
    background: var(--ink);
    color: var(--bg);
}

[data-theme="dark"] .protected-file-download {
    color: var(--accent);
    border-color: var(--accent);
}

[data-theme="dark"] .protected-file-download:hover {
    background: var(--accent);
    color: var(--bg);
}

[data-theme="dark"] .week-status-soon {
    background: var(--surface-alt);
    color: var(--ink-soft);
}

[data-theme="dark"] .document-item.is-available {
    border-color: var(--accent);
    border-top-color: var(--accent);
    background: var(--surface);
}

[data-theme="dark"] .nav-links a {
    color: var(--ink-soft);
}

[data-theme="dark"] .nav-links a:hover,
[data-theme="dark"] .nav-links a.active {
    color: var(--ink);
}

[data-theme="dark"] .nav-links a.active {
    border-bottom-color: var(--accent);
}

[data-theme="dark"] .quick-links-mobile {
    background: rgba(10, 10, 10, 0.96);
    border-bottom-color: var(--line);
}

[data-theme="dark"] .quick-links-mobile a {
    background: var(--surface);
    border-color: var(--line);
    color: var(--ink-muted);
}

[data-theme="dark"] .quick-links-mobile a:hover,
[data-theme="dark"] .quick-links-mobile a:focus-visible {
    border-color: var(--ink-soft);
    color: var(--ink);
}

[data-theme="dark"] .text-link,
[data-theme="dark"] .materials-strip a,
[data-theme="dark"] .material-list a,
[data-theme="dark"] .material-note a,
[data-theme="dark"] .document-action,
[data-theme="dark"] .protected-file-download {
    color: var(--accent);
}

[data-theme="dark"] .text-link:hover,
[data-theme="dark"] .materials-strip a:hover,
[data-theme="dark"] .material-list a:hover,
[data-theme="dark"] .material-note a:hover,
[data-theme="dark"] .document-action:hover {
    color: #F8A09E;
}

[data-theme="dark"] .resource-column a {
    color: var(--ink-muted);
}

[data-theme="dark"] .resource-column a:hover {
    color: var(--accent);
}

[data-theme="dark"] .placeholder-text,
[data-theme="dark"] .material-note,
[data-theme="dark"] .pdf-updated-meta,
[data-theme="dark"] .protected-file-meta,
[data-theme="dark"] .week-updated {
    color: var(--ink-soft);
}

[data-theme="dark"] .autofile-link:not([href]),
[data-theme="dark"] .autofile-link[aria-disabled="true"],
[data-theme="dark"] .inactive-file-link {
    color: #666666 !important;
    text-decoration-color: #666666;
    opacity: 0.78;
}

/* ═══════════════════════════════════════════════════
   Course description expand/collapse
   ═══════════════════════════════════════════════════ */
.course-description {
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}