:root {
  --bg: #ffffff;
  --fg: #0a0a0a;
  --muted: #666;
  --border: #e6e6e6;
  --elev: #f7f7f7;
  --accent: #111; /* subtle, not colorful */
  --radius: 12px;
  --shadow: 0 1px 2px rgba(0,0,0,0.06), 0 8px 24px rgba(0,0,0,0.06);
}

[data-theme="dark"] {
  --bg: #0a0a0a;
  --fg: #f5f5f5;
  --muted: #b5b5b5;
  --border: #1d1d1d;
  --elev: #121212;
  --accent: #fafafa;
  --shadow: 0 1px 2px rgba(0,0,0,0.4), 0 8px 24px rgba(0,0,0,0.3);
}

/* Base */
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: "Noto Sans", system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.6;
}

.mono { font-family: "Space Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }

.container {
  width: min(1100px, 92vw);
  margin: 0 auto;
}

.section { padding: 72px 0; }
.section-alt { background: var(--elev); }

h1, h2, h3 {
  line-height: 1.2;
  margin: 0 0 12px;
}
h1 { font-size: clamp(2.2rem, 3.5vw, 3rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.6rem, 2.5vw, 2.2rem); }
h3 { font-size: clamp(1.2rem, 1.8vw, 1.3rem); }

p { margin: 0 0 12px; color: var(--fg); }

.list { margin: 0; padding-left: 18px; }
.list li { margin: 6px 0; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  backdrop-filter: saturate(1.1) blur(6px);
  background: color-mix(in oklab, var(--bg), transparent 10%);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 12px min(4vw, 24px);
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; }
.logo-dot { width: 10px; height: 10px; border-radius: 50%; background: var(--accent); display: inline-block; }
.brand-text { letter-spacing: 0.02em; }

.main-nav ul {
  display: flex; gap: 12px; list-style: none; margin: 0; padding: 0;
}
.main-nav a, .theme-toggle, .nav-toggle {
  color: var(--fg); text-decoration: none; padding: 8px 12px; border-radius: 8px; border: 1px solid transparent;
}
.main-nav a:hover, .theme-toggle:hover { border-color: var(--border); background: var(--elev); }
.nav-toggle { display: none; background: transparent; }

@media (max-width: 820px) {
  .nav-toggle { display: inline-block; }
  .main-nav ul { display: none; position: absolute; right: 12px; top: 56px; background: var(--bg); border: 1px solid var(--border); border-radius: 10px; padding: 8px; box-shadow: var(--shadow); }
  .main-nav ul[aria-expanded="true"], .main-nav[aria-expanded="true"] ul { display: flex; flex-direction: column; min-width: 200px; }
}

/* Hero */
.hero {
  display: grid; grid-template-columns: 1.1fr 1fr; align-items: center; gap: 24px;
  padding: clamp(36px, 5vw, 72px) 0;
}
.hero-inner { padding-left: min(4vw, 24px); }
.hero-visual { display: grid; place-items: center; }
.hero-svg { width: min(420px, 70vw); height: auto; }
.ring { fill: none; stroke: var(--border); stroke-width: 1; }
.axis { stroke: var(--border); stroke-width: 1; }

.hero-title { margin-bottom: 8px; }
.hero-subtitle { color: var(--muted); max-width: 52ch; }
.hero-cta { margin-top: 16px; display: flex; gap: 10px; flex-wrap: wrap; }

@media (max-width: 960px) {
  .hero { grid-template-columns: 1fr; }
  .hero-inner { order: 2; padding: 0 min(4vw, 24px); }
  .hero-visual { order: 1; }
}

/* Buttons */
.btn {
  border: 1px solid var(--border);
  background: transparent;
  color: var(--fg);
  padding: 10px 14px;
  border-radius: 10px;
  transition: transform .08s ease, background .2s ease, border-color .2s ease;
}
.btn:hover { transform: translateY(-1px); border-color: var(--fg); }
.btn:active { transform: translateY(0); }
.btn.primary { background: var(--fg); color: var(--bg); border-color: var(--fg); }
.btn.primary:hover { filter: contrast(1.05) brightness(0.98); }
.btn.small { padding: 6px 10px; font-size: 0.9rem; }
.btn.outline { background: transparent; }

/* Cards and grids */
.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
}

.grid.two {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-bottom: 16px;
}
.grid.three {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px;
}
@media (max-width: 860px) {
  .grid.two, .grid.three { grid-template-columns: 1fr; }
}

/* Compass */
.compass-wrap {
  display: grid; grid-template-columns: 1fr 320px; gap: 24px; align-items: start;
}
@media (max-width: 940px) {
  .compass-wrap { grid-template-columns: 1fr; }
}

.compass { display: grid; gap: 16px; }
.compass-face {
  width: min(520px, 86vw);
  aspect-ratio: 1/1;
  margin: 0 auto;
  background: radial-gradient(ellipse at center, color-mix(in oklab, var(--elev), transparent 0%), var(--elev));
  border: 1px solid var(--border);
  border-radius: 50%;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow);
  touch-action: none;
  user-select: none;
}
.compass-face:focus { outline: 2px solid var(--border); }

.tick { position: absolute; left: 50%; top: 50%; transform-origin: 0 0; }
.tick-line { width: 1px; background: var(--border); position: absolute; left: 0; top: -44%; height: 12%; }
.tick-line.major { height: 16%; background: var(--fg); }
.tick-line.cardinal { height: 20%; background: var(--fg); }
.tick-label {
  position: absolute; top: -60%; left: -12px;
  width: 24px; text-align: center; font-size: 0.8rem; color: var(--muted);
}
.tick-label.dir { top: -84%; font-weight: 700; color: var(--fg); }

.needle { position: absolute; inset: 0; }
.needle-north, .needle-south {
  position: absolute; left: 50%; top: 50%;
  width: 0; height: 0; border-left: 10px solid transparent; border-right: 10px solid transparent;
  transform: translate(-50%, -50%);
}
.needle-north { border-bottom: 110px solid var(--fg); }
.needle-south { border-top: 110px solid color-mix(in oklab, var(--fg), transparent 30%); }

.compass-status {
  display: grid; gap: 10px; align-items: center;
}
.readouts {
  display: grid; grid-template-columns: 1fr 1fr; gap: 10px;
}
.readout { background: var(--bg); border: 1px solid var(--border); border-radius: 10px; padding: 10px; text-align: center; }
.readout .label { display: block; font-size: 0.8rem; color: var(--muted); }
.readout .value { font-size: 1.4rem; font-weight: 700; }

.legend { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px; box-shadow: var(--shadow); }
.legend h3 { margin-bottom: 8px; }
.legend-list { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 6px 12px; }
.badge { display: inline-grid; place-items: center; width: 28px; height: 28px; border: 1px solid var(--border); border-radius: 8px; font-weight: 700; margin-right: 8px; }

/* Quiz */
.quiz { display: grid; gap: 16px; }
.q { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px; }
.q-text { margin-bottom: 8px; }
.options { display: grid; gap: 6px; }
.quiz-actions { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.quiz-result { min-width: 180px; font-weight: 700; }

.field { display: grid; gap: 6px; }
.field input {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border);
  background: var(--bg); color: var(--fg); border-radius: 10px;
}
.calc .fields { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 10px; }
.calc-actions { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 4px; }
.calc-out { display: block; margin-top: 8px; font-weight: 700; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 24px 0; }
.footer-inner { display: grid; gap: 4px; }
.muted { color: var(--muted); }

/* Accessibility */
.skip-link {
  position: absolute; left: -9999px; top: auto; width: 1px; height: 1px; overflow: hidden;
}
.skip-link:focus {
  position: fixed; left: 12px; top: 12px; width: auto; height: auto;
  padding: 8px 12px; background: var(--fg); color: var(--bg); border-radius: 8px;
}