/* ============================================================
   Fun With Math – Global Stylesheet
   ============================================================ */

:root {
  --bg: #0d1117;
  --surface: #161b22;
  --border: #30363d;
  --accent: #58a6ff;
  --accent2: #bc8cff;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.5);
}

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

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family:
    'Segoe UI',
    system-ui,
    -apple-system,
    sans-serif;
  line-height: 1.6;
  min-height: 100vh;
}

/* ── Nav ─────────────────────────────────────────────────── */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 17, 23, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  height: 56px;
}

nav .brand {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
}

nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s;
}
nav a:hover {
  color: var(--text);
}

nav .spacer {
  flex: 1;
}

/* ── Page Header ─────────────────────────────────────────── */
.page-header {
  text-align: center;
  padding: 4rem 1.5rem 2.5rem;
}
.page-header h1 {
  font-size: clamp(1.8rem, 5vw, 3rem);
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.75rem;
}
.page-header p {
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto;
  font-size: 1.05rem;
}

/* ── Experiment Card Grid ────────────────────────────────── */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  max-width: 1100px;
  margin: 0 auto;
  padding: 1.5rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-decoration: none;
  color: var(--text);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition:
    border-color 0.25s,
    transform 0.25s,
    box-shadow 0.25s;
}
.card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.card-icon {
  font-size: 2.5rem;
  line-height: 1;
}
.card h2 {
  font-size: 1.15rem;
  color: var(--accent);
}
.card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  flex: 1;
}
.card .tag {
  display: inline-block;
  font-size: 0.75rem;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: rgba(88, 166, 255, 0.12);
  color: var(--accent);
  border: 1px solid rgba(88, 166, 255, 0.25);
}

/* ── Experiment Page Layout ──────────────────────────────── */
.experiment-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 1.5rem;
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.5rem;
  align-items: start;
}

@media (max-width: 800px) {
  .experiment-layout {
    grid-template-columns: 1fr;
  }
}

.canvas-wrapper {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.canvas-wrapper canvas {
  display: block;
  max-width: 100%;
  height: auto;
}

/* ── Controls Panel ──────────────────────────────────────── */
.controls {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.controls h3 {
  font-size: 1rem;
  color: var(--accent);
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.5rem;
}
.controls label {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.controls label span {
  color: var(--text);
  font-size: 0.8rem;
}
.controls input[type='range'] {
  width: 100%;
  accent-color: var(--accent);
  cursor: pointer;
}
.controls select,
.controls input[type='number'],
.controls input[type='text'] {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  padding: 0.35rem 0.6rem;
  font-size: 0.875rem;
  width: 100%;
}
.controls select:focus,
.controls input:focus {
  outline: none;
  border-color: var(--accent);
}

/* ── Buttons ─────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 600;
  transition:
    opacity 0.2s,
    transform 0.1s;
  text-decoration: none;
}
.btn:active {
  transform: scale(0.97);
}
.btn-primary {
  background: var(--accent);
  color: #0d1117;
}
.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

/* ── Info Box ────────────────────────────────────────────── */
.info-box {
  background: rgba(88, 166, 255, 0.07);
  border: 1px solid rgba(88, 166, 255, 0.2);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.7;
}
.info-box h4 {
  color: var(--accent);
  margin-bottom: 0.4rem;
  font-size: 0.95rem;
}
.info-box code {
  background: rgba(255, 255, 255, 0.06);
  border-radius: 4px;
  padding: 0.1em 0.35em;
  font-family: 'Fira Code', Consolas, monospace;
  font-size: 0.85em;
  color: var(--accent2);
}

/* ── Footer ──────────────────────────────────────────────── */
footer {
  text-align: center;
  padding: 2rem 1rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}
footer a {
  color: var(--accent);
  text-decoration: none;
}
footer a:hover {
  text-decoration: underline;
}