html {
    scroll-behavior: smooth;
}

/* Dark mode variables */
:root {
    --background: #ffffff;
    --text: #363636;
    --border: #dbdbdb;
    --card-background: #ffffff;
    --card-border: #dbdbdb;
}

[data-theme="dark"] {
    --background: #1a1a1a;
    --text: #f5f5f5;
    --border: #363636;
    --card-background: #2a2a2a;
    --card-border: #363636;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text);
    background-color: var(--background);
    transition: background-color 0.3s, color 0.3s;
}

[data-theme="dark"] .title,
[data-theme="dark"] .subtitle {
    color: var(--text);
}

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

.section {
    padding: 2rem 1.5rem;
}

.title, .subtitle {
    font-weight: 300;
}

.content {
    max-width: 1000px;
    margin: 0 auto;
    background-color: var(--background);
    color: var(--text);
}

.divider {
    background-color: #cacaca;
    height: 0.2rem;
}

.author-info {
    margin-top: 1.5rem;
}

.author-info a {
    color: inherit;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #3273dc;
}

[data-theme="dark"] a:hover {
    color: #64b5f6;
}

.image-card {
    margin-bottom: 0rem;
    background-color: var(--card-background);
    border: 1px solid var(--card-border);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
    height: 100%;
}

.image-card img {
    width: 100%;
    height: 220px;
    object-fit: cover;
    display: block;
}

.image-card video {
    width: 100%;
    height: auto;
    display: block;
}

.video-grid {
    display: grid;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.video-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.video-grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.video-grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
.video-grid.cols-5 { grid-template-columns: repeat(5, 1fr); }

@media (max-width: 768px) {
    .video-grid.cols-3,
    .video-grid.cols-4,
    .video-grid.cols-5 { grid-template-columns: repeat(2, 1fr); }
}

.video-tile {
    background-color: var(--card-background);
    border: 1px solid var(--card-border);
    border-radius: 6px;
    overflow: hidden;
    box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.video-tile video {
    width: 100%;
    height: auto;
    display: block;
}

.video-tile .caption {
    padding: 0.35rem 0.5rem;
    font-size: 0.82em;
    text-align: center;
    line-height: 1.25;
    color: var(--text);
}

.video-tile .caption .label {
    font-weight: 600;
    color: var(--text);
}

.video-tile .caption .sr {
    display: block;
    font-size: 0.92em;
    color: var(--text);
    opacity: 0.85;
}

[data-theme="dark"] .video-tile .caption,
[data-theme="dark"] .video-tile .caption .label,
[data-theme="dark"] .video-tile .caption .sr {
    color: #f5f5f5;
}

[data-theme="dark"] .video-tile .caption .sr {
    opacity: 0.9;
}

/* Diagram figure — image has dark text, needs a light backdrop in both themes. */
.diagram-figure {
    background-color: #f0f0f0;
    border-color: #d0d0d0;
    margin-bottom: 1rem;
}

.diagram-figure img {
    display: block;
    width: 100%;
    height: auto;
    background-color: #f0f0f0;
    padding: 0.75rem;
    box-sizing: border-box;
}

[data-theme="dark"] .diagram-figure {
    background-color: #e0e0e0;
    border-color: #a0a0a0;
}

[data-theme="dark"] .diagram-figure img {
    background-color: #e0e0e0;
}

/* Code blocks + inline code for the planning-language walkthrough */
pre.code-block {
    background-color: #f5f5f5;
    border: 1px solid #d8d8d8;
    border-radius: 6px;
    padding: 0.75rem 0.9rem;
    font-size: 0.82em;
    line-height: 1.45;
    overflow-x: auto;
    margin: 0.5rem 0 1rem 0;
    color: #2a2a2a;
}

code.inline {
    background-color: #efefef;
    border-radius: 4px;
    padding: 0.05rem 0.3rem;
    font-size: 0.9em;
    color: #363636;
}

[data-theme="dark"] pre.code-block {
    background-color: #262626;
    border-color: #3a3a3a;
    color: #e8e8e8;
}

[data-theme="dark"] code.inline {
    background-color: #2e2e2e;
    color: #f0f0f0;
}

details.walkthrough {
    border: 1px solid var(--card-border);
    border-radius: 6px;
    padding: 0.4rem 0.9rem;
    margin-bottom: 0.6rem;
    background-color: var(--card-background);
}

details.walkthrough > summary {
    cursor: pointer;
    font-weight: 500;
    padding: 0.35rem 0;
    list-style: none;
    color: var(--text);
}

details.walkthrough > summary::marker,
details.walkthrough > summary::-webkit-details-marker { display: none; }

details.walkthrough > summary::before {
    content: "▸ ";
    display: inline-block;
    width: 1em;
    transition: transform 0.15s ease;
}

details.walkthrough[open] > summary::before {
    content: "▾ ";
}

details.walkthrough > *:not(summary) {
    font-size: 0.93em;
}

.toc {
    border: 1px solid var(--card-border);
    border-radius: 6px;
    padding: 0.75rem 1rem;
    background-color: var(--card-background);
    margin: 1rem 0 1.5rem 0;
    font-size: 0.92em;
}

.toc-title {
    font-weight: 500;
    margin-bottom: 0.4rem;
    color: var(--text);
}

.toc ol {
    columns: 2;
    column-gap: 1.75rem;
    margin: 0;
    padding-left: 1.25rem;
}

.toc li {
    break-inside: avoid;
    margin-bottom: 0.1rem;
}

.toc .toc-sub {
    list-style: disc;
    padding-left: 1.2rem;
    margin: 0.1rem 0 0.25rem 0;
    font-size: 0.92em;
    opacity: 0.85;
}

.toc .toc-sub li { margin-bottom: 0.05rem; }

.toc a {
    color: var(--text);
    text-decoration: none;
}

.toc a:hover { color: #3273dc; }
[data-theme="dark"] .toc a:hover { color: #64b5f6; }

@media (max-width: 600px) {
    .toc ol { columns: 1; }
}

.figure-caption {
    font-size: 0.9em;
    margin-top: 0.75rem;
    text-align: left;
}

.anon-note {
    font-style: italic;
    opacity: 0.75;
    font-size: 0.9em;
}

.dark-mode-toggle {
    position: fixed;
    bottom: 2rem;
    right: 3rem;
    z-index: 1000;
    background-color: var(--card-background);
    color: var(--text);
    border-color: var(--border);
    transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.dark-mode-toggle:hover {
    background-color: var(--text);
    color: var(--background);
}

.button {
    background-color: var(--card-background);
    color: var(--text);
    border-color: var(--border);
    transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

[data-theme="dark"] .button {
    background-color: #363636;
    color: #f5f5f5;
    border-color: #4a4a4a;
}

.button:hover {
    background-color: #fcfcfc;
    color: #363636;
}

[data-theme="dark"] .button:hover {
    background-color: #4a4a4a;
    color: #f5f5f5;
}