:root {
  --font-sans: 'IBM Plex Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'IBM Plex Mono', ui-monospace, SFMono-Regular, monospace;
  --max-width: 1200px;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --transition-fast: 120ms ease;
  --transition-normal: 200ms ease;
  --transition-slow: 300ms ease;

  /* Light theme (default) - warm technical */
  --bg: #f6f5f2;
  --bg-elevated: #fefefe;
  --bg-card: #ffffff;
  --bg-hover: #ebe9e4;
  --border: #d4d2cc;
  --border-strong: #b8b5ad;
  --fg: #1a1917;
  --fg-muted: #4a4844;
  --fg-subtle: #6a6864;
  --accent: #1e6b35;
  --accent-hover: #185a2d;
  --accent-muted: #dcf0e0;
  --accent-border: #a8d4b8;
  --success: #1e6b35;
  --success-muted: #dcf0e0;
  --success-border: #a8d4b8;
  --warning: #a06800;
  --warning-muted: #fef3e0;
  --warning-border: #e8d0a0;
  --error: #a82e1f;
  --error-muted: #fcecec;
  --error-border: #e8b8b8;
  --code-bg: #1a1a2e;
  --code-fg: #e4e4e7;
  --header-bg: rgba(254, 254, 254, 0.92);
  --shadow-sm: 0 1px 2px rgba(26, 25, 23, 0.04);
  --shadow-md: 0 4px 16px rgba(26, 25, 23, 0.06);
  --shadow-lg: 0 8px 28px rgba(26, 25, 23, 0.08);
  --focus-ring: 0 0 0 3px var(--accent-muted);
}

[data-theme="dark"] {
  --bg: #0f0e0d;
  --bg-elevated: #181715;
  --bg-card: #1d1b19;
  --bg-hover: #25221f;
  --border: #33302c;
  --border-strong: #4a453f;
  --fg: #f5f3f0;
  --fg-muted: #c8c4bc;
  --fg-subtle: #9a958d;
  --accent: #4ade80;
  --accent-hover: #5ee090;
  --accent-muted: #1a3520;
  --accent-border: #2d6b3f;
  --success: #4ade80;
  --success-muted: #1a3520;
  --success-border: #2d6b3f;
  --warning: #fbbf24;
  --warning-muted: #352d0a;
  --warning-border: #6b5a1a;
  --error: #f87171;
  --error-muted: #fcecec;
  --error-border: #f5c0c0;
  --code-bg: #0d0c0a;
  --code-fg: #e4e4e7;
  --header-bg: rgba(15, 14, 13, 0.92);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 28px rgba(0, 0, 0, 0.35);
  --focus-ring: 0 0 0 3px var(--accent-muted);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
body { font-family: var(--font-sans); font-size: 1rem; line-height: 1.7; color: var(--fg); background-color: var(--bg); background-image: radial-gradient(ellipse at top, var(--bg-hover) 0%, transparent 50%); background-attachment: fixed; transition: background-color var(--transition-normal), color var(--transition-normal), border-color var(--transition-normal), background-image var(--transition-normal); }
a { color: var(--accent); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--accent-hover); text-decoration: underline; }
a:focus-visible { outline: none; box-shadow: var(--focus-ring); border-radius: var(--radius-sm); }
h1, h2, h3, h4, h5, h6 { font-weight: 600; line-height: 1.25; color: var(--fg); }
h1 { font-size: clamp(2.25rem, 5vw, 3.75rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.75rem, 3.5vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 2.5vw, 1.75rem); }
p { margin-bottom: var(--spacing-md); color: var(--fg-muted); }
code, pre, kbd, samp { font-family: var(--font-mono); font-size: 0.875em; }
code { background: var(--bg-hover); padding: 0.125rem 0.375rem; border-radius: var(--radius-sm); border: 1px solid var(--border); color: var(--accent); }
pre { background: var(--code-bg); color: var(--code-fg); border: 1px solid var(--border); border-radius: var(--radius-md); padding: var(--spacing-md); overflow-x: auto; margin-bottom: var(--spacing-md); }
pre code { background: transparent; padding: 0; border: none; font-size: 0.875rem; line-height: 1.6; color: inherit; }
img { max-width: 100%; height: auto; display: block; }
ul, ol { padding-left: var(--spacing-xl); color: var(--fg-muted); }
li { margin-bottom: var(--spacing-xs); }
.container { width: 100%; max-width: var(--max-width); margin: 0 auto; padding: 0 var(--spacing-md); }
.section { padding: var(--spacing-2xl) 0; }
.section-title { margin-bottom: var(--spacing-lg); padding-bottom: var(--spacing-sm); border-bottom: 1px solid var(--border); position: relative; }
.section-title::after { content: ''; position: absolute; bottom: -1px; left: 0; width: 60px; height: 2px; background: var(--accent); border-radius: 1px; }
.skip-link { position: absolute; top: -100%; left: 50%; transform: translateX(-50%); background: var(--accent); color: var(--bg); padding: var(--spacing-sm) var(--spacing-md); border-radius: var(--radius-md); font-weight: 600; font-size: 0.875rem; z-index: 1000; transition: top var(--transition-fast); }
.skip-link:focus { top: var(--spacing-md); }

.badge { display: inline-flex; align-items: center; padding: 0.1875rem 0.5625rem; font-size: 0.7rem; font-weight: 600; border-radius: var(--radius-sm); border: 1px solid; white-space: nowrap; letter-spacing: 0.02em; text-transform: uppercase; }
.badge-done { background: var(--success-muted); color: var(--success); border-color: var(--success-border); }
.badge-progress { background: var(--warning-muted); color: var(--warning); border-color: var(--warning-border); }
.badge-planned { background: var(--accent-muted); color: var(--accent); border-color: var(--accent-border); }

.card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: var(--spacing-xl); transition: border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast); }
.card:hover { border-color: var(--border-strong); box-shadow: var(--shadow-md); transform: translateY(-1px); }
.card:focus-within { box-shadow: var(--focus-ring); }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: var(--spacing-sm); padding: var(--spacing-sm) var(--spacing-xl); font-family: var(--font-sans); font-size: 0.875rem; font-weight: 500; border-radius: var(--radius-md); border: 1px solid transparent; cursor: pointer; transition: all var(--transition-fast); text-decoration: none; }
.btn-primary { background: var(--accent); color: var(--bg); border-color: var(--accent); }
.btn-primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: var(--bg); text-decoration: none; }
.btn-secondary { background: transparent; color: var(--fg); border-color: var(--border); }
.btn-secondary:hover { background: var(--bg-hover); border-color: var(--border-strong); color: var(--fg); text-decoration: none; }
.btn-ghost { background: transparent; color: var(--fg-muted); border-color: transparent; }
.btn-ghost:hover { background: var(--bg-hover); color: var(--fg); text-decoration: none; }

.text-center { text-align: center; }
.text-muted { color: var(--fg-muted); }
.text-subtle { color: var(--fg-subtle); }
.text-accent { color: var(--accent); }

.mt-xs { margin-top: var(--spacing-xs); } .mt-sm { margin-top: var(--spacing-sm); } .mt-md { margin-top: var(--spacing-md); } .mt-lg { margin-top: var(--spacing-lg); } .mt-xl { margin-top: var(--spacing-xl); }
.mb-xs { margin-bottom: var(--spacing-xs); } .mb-sm { margin-bottom: var(--spacing-sm); } .mb-md { margin-bottom: var(--spacing-md); } .mb-lg { margin-bottom: var(--spacing-lg); } .mb-xl { margin-bottom: var(--spacing-xl); }

/* Theme toggle */
.theme-toggle { display: inline-flex; align-items: center; justify-content: center; width: 40px; height: 40px; border-radius: var(--radius-md); background: var(--bg-hover); border: 1px solid var(--border); color: var(--fg-muted); cursor: pointer; transition: all var(--transition-fast); }
.theme-toggle:hover { background: var(--bg-card); border-color: var(--border-strong); color: var(--fg); }
.theme-toggle:focus-visible { box-shadow: var(--focus-ring); }
.theme-toggle svg { width: 20px; height: 20px; stroke: currentColor; }
.theme-toggle .sun-icon { display: none; }
.theme-toggle .moon-icon { display: block; }
[data-theme="dark"] .theme-toggle .sun-icon { display: block; }
[data-theme="dark"] .theme-toggle .moon-icon { display: none; }

@media (max-width: 640px) {
  :root { --spacing-2xl: 2rem; --spacing-xl: 1.5rem; --spacing-lg: 1.25rem; }
  html { font-size: 15px; }
  body { background-attachment: scroll; }
}

/* Hero */
.hero { padding: var(--spacing-2xl) 0 var(--spacing-xl); min-height: calc(100vh - 72px); display: flex; align-items: center; }
.hero-content { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--spacing-md); }
.hero-badges { display: flex; flex-wrap: wrap; gap: var(--spacing-sm); margin-bottom: var(--spacing-lg); }
.hero-title { font-weight: 700; letter-spacing: -0.02em; margin-bottom: var(--spacing-md); line-height: 1.15; }
.hero-subtitle { display: block; font-weight: 400; font-size: 0.55em; color: var(--fg-muted); margin-top: var(--spacing-xs); letter-spacing: 0.01em; }
.hero-description { font-size: 1.1875rem; max-width: 65ch; margin-bottom: var(--spacing-xl); line-height: 1.8; color: var(--fg-muted); }
.hero-actions { display: flex; flex-wrap: wrap; gap: var(--spacing-md); margin-bottom: var(--spacing-2xl); }
.hero-terminal { background: var(--code-bg); border: 1px solid var(--border); border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-lg); max-width: 100%; }
.terminal-header { background: var(--bg-elevated); border-bottom: 1px solid var(--border); padding: var(--spacing-sm) var(--spacing-md); display: flex; align-items: center; gap: var(--spacing-md); }
.terminal-dots { display: flex; gap: 6px; }
.terminal-dots span { width: 12px; height: 12px; border-radius: 50%; background: var(--border-strong); }
.terminal-dots span:nth-child(1) { background: var(--error); }
.terminal-dots span:nth-child(2) { background: var(--warning); }
.terminal-dots span:nth-child(3) { background: var(--success); }
.terminal-title { font-family: var(--font-mono); font-size: 0.7rem; color: var(--fg-subtle); letter-spacing: 0.02em; }
.terminal-body { padding: var(--spacing-md); max-height: 360px; overflow-y: auto; }
.terminal-body pre { margin: 0; background: transparent; border: none; font-size: 0.8rem; line-height: 1.7; }
.term-prompt { color: var(--success); font-weight: 500; }
.term-command { color: var(--accent); }
.term-output { color: var(--fg-muted); }
.term-cursor { animation: blink 1s infinite; color: var(--fg); }
@keyframes blink { 0%, 50% { opacity: 1; } 51%, 100% { opacity: 0; } }
@media (max-width: 640px) { .hero { padding: var(--spacing-xl) 0; min-height: auto; } .terminal-body { max-height: 260px; } .hero-description { font-size: 1.125rem; } }

/* Progress */
.progress-header { display: flex; flex-wrap: wrap; align-items: flex-start; justify-content: space-between; gap: var(--spacing-md); margin-bottom: var(--spacing-xl); }
.progress-legend { display: flex; flex-wrap: wrap; gap: var(--spacing-sm); }
.progress-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: var(--spacing-lg); }
.progress-card { display: flex; flex-direction: column; }
.progress-card-header { display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between; gap: var(--spacing-sm); margin-bottom: var(--spacing-sm); }
.progress-card-title { font-size: 1.0625rem; font-weight: 600; color: var(--fg); line-height: 1.35; }
.progress-card-desc { font-size: 0.9rem; color: var(--fg-muted); margin: 0; flex: 1; }
@media (max-width: 640px) { .progress-grid { grid-template-columns: 1fr; } .progress-card-title { font-size: 1rem; } }

/* Roadmap */
.roadmap-groups { display: grid; gap: var(--spacing-xl); }
.roadmap-group { background: var(--bg-elevated); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: var(--spacing-xl); }
.roadmap-group-header { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--spacing-md); margin-bottom: var(--spacing-lg); padding-bottom: var(--spacing-md); border-bottom: 1px solid var(--border); }
.roadmap-group-title { display: flex; align-items: center; gap: var(--spacing-md); }
.roadmap-group-number { font-family: var(--font-mono); font-size: 0.75rem; font-weight: 600; color: var(--fg-subtle); text-transform: uppercase; letter-spacing: 0.05em; }
.roadmap-group-name { font-size: 1.25rem; font-weight: 600; color: var(--fg); }
.roadmap-group-badge { font-size: 0.7rem; font-weight: 600; padding: 0.1875rem 0.5625rem; border-radius: var(--radius-sm); text-transform: uppercase; letter-spacing: 0.02em; }
.roadmap-group-badge.complete { background: var(--success-muted); color: var(--success); border: 1px solid var(--success-border); }
.roadmap-group-badge.current { background: var(--warning-muted); color: var(--warning); border: 1px solid var(--warning-border); }
.roadmap-group-badge.upcoming { background: var(--accent-muted); color: var(--accent); border: 1px solid var(--accent-border); }
.roadmap-group-items { display: grid; gap: var(--spacing-sm); }
.roadmap-group-item { display: flex; align-items: flex-start; gap: var(--spacing-md); padding: var(--spacing-sm) 0; transition: opacity var(--transition-fast); }
.roadmap-group-item:hover { opacity: 0.8; }
.roadmap-item-checkbox { flex-shrink: 0; width: 22px; height: 22px; margin-top: 2px; border: 2px solid var(--border); border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center; transition: all var(--transition-fast); background: var(--bg-card); }
.roadmap-group-item.done .roadmap-item-checkbox { background: var(--success); border-color: var(--success); color: var(--bg); }
.roadmap-group-item.done .roadmap-item-checkbox::before { content: '✓'; font-size: 0.75rem; font-weight: 700; }
.roadmap-item-text { font-family: var(--font-mono); font-size: 0.85rem; line-height: 1.6; color: var(--fg-muted); }
.roadmap-group-item.done .roadmap-item-text { color: var(--fg); }
@media (max-width: 640px) { .roadmap-group-header { flex-direction: column; align-items: flex-start; } .roadmap-item-text { font-size: 0.8125rem; } }

/* Commits */
.section-header { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--spacing-md); margin-bottom: var(--spacing-lg); }
.section-header .section-title { margin-bottom: 0; border-bottom: none; padding-bottom: 0; }
.commits-loading { display: flex; align-items: center; justify-content: center; gap: var(--spacing-md); padding: var(--spacing-xl); color: var(--fg-muted); }
.loading-spinner { width: 28px; height: 28px; border: 2px solid var(--border); border-top-color: var(--accent); border-radius: 50%; animation: spin 1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.commits-error { border-color: var(--error); background: var(--error-muted); color: var(--error); max-width: 600px; margin: 0 auto; }
.commits-list { list-style: none; padding: 0; margin: 0; display: grid; gap: var(--spacing-md); }
.commit-item { display: flex; flex-direction: column; }
.commit-content { display: flex; flex-direction: column; gap: var(--spacing-sm); }
.commit-header { display: flex; flex-wrap: wrap; align-items: baseline; gap: var(--spacing-md); margin-bottom: var(--spacing-xs); }
.commit-sha { font-family: var(--font-mono); font-size: 0.8125rem; font-weight: 500; color: var(--accent); background: var(--accent-muted); padding: 0.1875rem 0.5625rem; border-radius: var(--radius-sm); border: 1px solid var(--accent-border); transition: all var(--transition-fast); text-decoration: none; }
.commit-sha:hover { background: var(--accent); border-color: var(--accent); color: var(--bg); text-decoration: none; }
.commit-date { font-family: var(--font-mono); font-size: 0.75rem; color: var(--fg-subtle); white-space: nowrap; }
.commit-message { margin: 0; font-size: 0.9375rem; color: var(--fg); line-height: 1.6; font-weight: 400; }
.commit-message a { color: var(--fg); text-decoration: none; transition: color var(--transition-fast); font-weight: 500; }
.commit-message a:hover { color: var(--accent); text-decoration: underline; }
.commit-author { display: flex; align-items: center; gap: var(--spacing-xs); font-size: 0.75rem; color: var(--fg-subtle); }
.commit-author svg { flex-shrink: 0; }
.commits-empty { padding: var(--spacing-xl); color: var(--fg-muted); }
@media (max-width: 640px) { .section-header { flex-direction: column; align-items: flex-start; } .commit-header { flex-direction: column; align-items: flex-start; gap: var(--spacing-xs); } .commit-message { font-size: 0.875rem; } }

/* About */
.about-content { display: grid; gap: var(--spacing-xl); max-width: 720px; }
.about-section h3 { font-size: 1.1875rem; font-weight: 600; margin-bottom: var(--spacing-md); color: var(--fg); }
.about-section p { margin-bottom: var(--spacing-md); line-height: 1.8; }
.about-section ul { list-style: disc; padding-left: var(--spacing-xl); }
.about-section li { margin-bottom: var(--spacing-sm); line-height: 1.8; }
.about-section code { font-size: 0.875em; background: var(--bg-hover); padding: 0.125rem 0.375rem; border-radius: var(--radius-sm); border: 1px solid var(--border); color: var(--accent); }
.about-section a { text-underline-offset: 3px; }
@media (max-width: 640px) { .about-content { gap: var(--spacing-lg); } }

/* Footer */
.footer { border-top: 1px solid var(--border); padding: var(--spacing-2xl) 0 var(--spacing-xl); background: var(--bg-elevated); margin-top: var(--spacing-2xl); background-image: radial-gradient(ellipse at top, var(--bg-hover) 0%, transparent 40%); }
.footer-grid { display: grid; grid-template-columns: 2fr repeat(3, 1fr); gap: var(--spacing-xl); margin-bottom: var(--spacing-xl); }
.footer-title { font-size: 1.375rem; font-weight: 700; margin-bottom: var(--spacing-xs); color: var(--fg); }
.footer-tagline { color: var(--fg-muted); font-size: 0.9375rem; margin-bottom: var(--spacing-sm); }
.footer-status { font-size: 0.8125rem; color: var(--accent); font-weight: 500; }
.footer-heading { font-size: 0.7rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; color: var(--fg-subtle); margin-bottom: var(--spacing-md); }
.footer-nav ul { list-style: none; padding: 0; margin: 0; display: grid; gap: var(--spacing-sm); }
.footer-nav a { font-size: 0.875rem; color: var(--fg-muted); transition: color var(--transition-fast); text-decoration: none; }
.footer-nav a:hover { color: var(--accent); text-decoration: none; }
.footer-bottom { padding-top: var(--spacing-lg); border-top: 1px solid var(--border); display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: var(--spacing-md); }
.footer-copyright { font-size: 0.875rem; color: var(--fg-subtle); margin: 0; }
.footer-note { font-size: 0.8125rem; color: var(--fg-subtle); margin: 0; }
.footer-note a { color: var(--fg-subtle); text-underline-offset: 2px; }
.footer-note a:hover { color: var(--accent); }
@media (max-width: 640px) { .footer-grid { grid-template-columns: 1fr 1fr; } .footer-brand { grid-column: 1 / -1; } .footer-bottom { flex-direction: column; text-align: center; } }
@media (max-width: 480px) { .footer-grid { grid-template-columns: 1fr; } }

/* Header */
.site-header { position: sticky; top: 0; z-index: 100; background: var(--header-bg); backdrop-filter: blur(12px); border-bottom: 1px solid var(--border); padding: var(--spacing-sm) 0; }
.header-nav { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: var(--spacing-md); }
.header-logo { display: flex; align-items: center; gap: var(--spacing-sm); font-weight: 700; font-size: 1.125rem; color: var(--fg); text-decoration: none; }
.header-logo:hover { color: var(--accent); text-decoration: none; }
.logo-icon { flex-shrink: 0; }
.header-links { display: flex; align-items: center; gap: var(--spacing-lg); list-style: none; margin: 0; padding: 0; }
.header-links a { font-size: 0.875rem; font-weight: 500; color: var(--fg-muted); text-decoration: none; transition: color var(--transition-fast); padding: var(--spacing-xs) 0; position: relative; }
.header-links a::after { content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 2px; background: var(--accent); transition: width var(--transition-fast); }
.header-links a:hover { color: var(--accent); text-decoration: none; }
.header-links a:hover::after { width: 100%; }
.header-github { display: flex; align-items: center; color: var(--fg-subtle) !important; padding: var(--spacing-xs); border-radius: var(--radius-sm); transition: all var(--transition-fast); }
.header-github:hover { color: var(--accent) !important; background: var(--bg-hover); }
@media (max-width: 768px) { .header-links { display: none; } .header-github { display: flex; } }

/* Page-specific: wider content for progress/roadmap */
.page-progress .progress-grid,
.page-roadmap .roadmap-groups,
.page-activity .commits-list {
  max-width: 100%;
}

/* Documentation page specific */
.about-section pre {
  background: var(--code-bg);
  color: var(--code-fg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
  font-size: 0.875rem;
  line-height: 1.6;
}
.about-section pre code {
  background: transparent;
  padding: 0;
  border: none;
  color: inherit;
  font-size: inherit;
}
.about-section table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-md) 0;
  font-size: 0.9rem;
}
.about-section th,
.about-section td {
  padding: var(--spacing-sm);
  border: 1px solid var(--border);
  text-align: left;
}
.about-section th {
  background: var(--bg-hover);
  font-weight: 600;
}