:root {
  --bg: #ffffff;
  --fg: #0e0e0f;
  --muted: #666;
  --card: #f7f7f8;
  --border: #e6e6e8;
  --accent: #111;
  --focus: 2px solid #0d6efd;
}

:root.dark {
  --bg: #0b0b0c;
  --fg: #f3f3f3;
  --muted: #b7b7b7;
  --card: #121214;
  --border: #1f1f22;
  --accent: #f5f5f5;
  --focus: 2px solid #9ecbff;
}

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

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  backdrop-filter: saturate(1.2) blur(10px);
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  border-bottom: 1px solid var(--border);
}
.container { width: min(1100px, 92vw); margin: 0 auto; }
.header-inner { display: flex; align-items: center; gap: 16px; padding: 14px 0; }
.brand { margin: 0; font-size: 1.25rem; letter-spacing: 0.2px; }
.nav { margin-left: auto; display: flex; gap: 18px; }
.nav a { text-decoration: none; color: var(--fg); opacity: 0.8; }
.nav a:hover { opacity: 1; }
.mode-toggle {
  border: 1px solid var(--border); background: var(--card); color: var(--fg);
  width: 36px; height: 36px; border-radius: 50%; cursor: pointer;
}

/* Hero */
.hero { padding: 56px 0 20px; border-bottom: 1px solid var(--border); }
.hero-inner { display: grid; grid-template-columns: 1.2fr 1fr; gap: 28px; align-items: center; }
.hero-copy h2 { margin: 0 0 8px; font-size: clamp(1.6rem, 2.3vw, 2.2rem); }
.hero-copy p { color: var(--muted); margin: 0 0 18px; }
.cta { display: inline-block; padding: 10px 14px; border: 1px solid var(--border); border-radius: 10px; text-decoration: none; color: var(--fg); background: var(--card); }
.cta:hover { transform: translateY(-1px); }
.moon-wrap { display:flex; justify-content:center; align-items:center; }
.moon-hero { width: 220px; height: 220px; }

/* Explore */
.explore { padding: 38px 0; }
.controls { display: grid; grid-template-columns: 240px 1fr; gap: 18px; align-items: end; }
.controls label { display: grid; gap: 6px; font-weight: 600; }
.controls input[type="date"] {
  padding: 10px 12px; border-radius: 10px; border:1px solid var(--border); background: var(--bg); color: var(--fg);
}
.slider-wrap { display: grid; gap: 6px; }
#daySlider { width: 100%; accent-color: var(--accent); }
.slider-legend { display:flex; justify-content:space-between; color: var(--muted); font-size: 0.9rem; }

.viewer { display: grid; grid-template-columns: 280px 1fr; gap: 24px; margin-top: 22px; align-items: center; }
.viewer-moon { display:flex; justify-content:center; }
.moon-svg { width: 240px; height: 240px; }
.phase-name { font-size: 1.3rem; font-weight: 800; margin-bottom: 6px; }
.stats { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 10px; margin-bottom: 10px; }
.stats .stat-label { display:block; color: var(--muted); font-size: 0.85rem; }
.stats .stat-value { display:block; font-weight: 700; }
.explain { color: var(--muted); margin: 0; }

/* Phases grid */
.phases { padding: 38px 0; border-top: 1px solid var(--border); }
.grid { display: grid; grid-template-columns: repeat(4, minmax(0,1fr)); gap: 16px; }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: 14px;
  padding: 14px; display: grid; gap: 8px; transition: transform 120ms ease;
}
.card:hover { transform: translateY(-2px); }
.card .title { font-weight: 700; }
.card .desc { color: var(--muted); font-size: 0.95rem; }
.card .mini {
  width: 56px; height: 56px; border-radius: 50%; border: 1px solid var(--border); background: radial-gradient(circle at 50% 45%, #f4f4f4, #dcdcdc 75%);
  position: relative; overflow: hidden;
}
.card .mini::after { content:""; position:absolute; inset:0; background: var(--mini-mask, transparent); }

/* Calendar */
.calendar { padding: 38px 0; border-top: 1px solid var(--border); }
.cal-header { display:flex; justify-content:space-between; align-items:center; margin-bottom: 12px; }
.cal-controls { display:flex; align-items:center; gap: 10px; }
.cal-controls button {
  border: 1px solid var(--border); background: var(--card); color: var(--fg);
  border-radius: 10px; padding: 6px 10px; cursor: pointer;
}
.cal-label { font-weight: 700; }
.cal-grid {
  display:grid; grid-template-columns: repeat(7, minmax(0,1fr)); gap: 10px;
}
.day {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 8px; min-height: 84px;
  display:grid; grid-template-rows: auto 1fr; gap: 6px; cursor: pointer;
}
.day .d { font-weight: 700; font-size: 0.95rem; opacity: 0.9; }
.day .moon {
  width: 34px; height: 34px; border-radius: 50%; background: radial-gradient(circle at 50% 45%, #f4f4f4, #dcdcdc 75%);
  position: relative; overflow: hidden; border: 1px solid var(--border);
}
.day .moon::after { content:""; position:absolute; inset:0; background: var(--mini-mask, transparent); }
.day.out { opacity: 0.35; }

/* FAQ */
.faq { padding: 38px 0; border-top: 1px solid var(--border); }
details { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 10px 12px; margin-bottom: 10px; }
summary { cursor: pointer; font-weight: 700; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 20px 0; color: var(--muted); font-size: 0.95rem; }

/* Accessibility */
:focus { outline: none; }
:focus-visible { outline: var(--focus); border-radius: 8px; }

/* Responsive */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .controls { grid-template-columns: 1fr; }
  .viewer { grid-template-columns: 1fr; }
  .grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
}
@media (max-width: 520px) {
  .grid { grid-template-columns: 1fr; }
}