/* SleepCalc — night theme. Vanilla CSS, no frameworks. Mobile-first. */
:root {
  --bg0: #070b1d;
  --bg1: #0d1330;
  --surface: rgba(255, 255, 255, 0.045);
  --surface-2: rgba(255, 255, 255, 0.07);
  --border: rgba(255, 255, 255, 0.10);
  --text: #eceefb;
  --muted: #a6aecf;
  --faint: #7c85ab;
  --amber: #f6b73c;
  --amber-soft: rgba(246, 183, 60, 0.14);
  --indigo: #8b93f8;
  --green: #4ade80;
  --radius: 18px;
  --maxw: 1060px;
  --serif: Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--sans);
  color: var(--text);
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(99, 102, 241, 0.22), transparent 60%),
    radial-gradient(900px 500px at 10% 0%, rgba(246, 183, 60, 0.07), transparent 55%),
    linear-gradient(180deg, var(--bg1), var(--bg0) 60%);
  min-height: 100vh;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* starfield */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    radial-gradient(1px 1px at 12% 22%, #fff 60%, transparent),
    radial-gradient(1px 1px at 32% 8%, #fff 60%, transparent),
    radial-gradient(1.5px 1.5px at 55% 18%, #fff 60%, transparent),
    radial-gradient(1px 1px at 71% 32%, #fff 60%, transparent),
    radial-gradient(1px 1px at 88% 12%, #fff 60%, transparent),
    radial-gradient(1.5px 1.5px at 44% 34%, #fff 60%, transparent),
    radial-gradient(1px 1px at 22% 44%, #fff 60%, transparent),
    radial-gradient(1px 1px at 63% 46%, #fff 60%, transparent),
    radial-gradient(1px 1px at 5% 60%, #fff 60%, transparent),
    radial-gradient(1.5px 1.5px at 80% 58%, #fff 60%, transparent),
    radial-gradient(1px 1px at 38% 66%, #fff 60%, transparent),
    radial-gradient(1px 1px at 92% 74%, #fff 60%, transparent),
    radial-gradient(1px 1px at 18% 82%, #fff 60%, transparent),
    radial-gradient(1.5px 1.5px at 52% 88%, #fff 60%, transparent);
  opacity: 0.5;
  z-index: 0;
}

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; position: relative; z-index: 1; }

/* header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(7, 11, 29, 0.72);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 50;
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; padding-top: 12px; padding-bottom: 12px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-family: var(--serif); font-size: 1.25rem; letter-spacing: 0.02em; }
.brand svg { width: 30px; height: 30px; flex: none; }
.brand small { font-family: var(--sans); font-size: 0.68rem; color: var(--faint); display: block; line-height: 1.2; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; }
.nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.86rem;
  padding: 8px 12px;
  border-radius: 999px;
  transition: background 0.2s, color 0.2s;
}
.nav a:hover { background: var(--surface-2); color: var(--text); }
.nav a.active { background: var(--amber-soft); color: var(--amber); }

/* hero */
.hero { text-align: center; padding: 56px 0 28px; }
.hero .moon { width: 84px; height: 84px; margin: 0 auto 18px; filter: drop-shadow(0 0 26px rgba(246, 183, 60, 0.45)); }
.hero h1 { font-family: var(--serif); font-weight: 500; font-size: clamp(1.9rem, 5vw, 3rem); margin: 0 0 12px; line-height: 1.2; }
.hero h1 .accent { color: var(--amber); font-style: italic; }
.hero p.lead { color: var(--muted); font-size: 1.06rem; max-width: 640px; margin: 0 auto; }

/* calculator card */
.calc-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(20px, 4vw, 36px);
  margin: 28px auto 8px;
  max-width: 680px;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
}
.tabs { display: flex; gap: 8px; margin-bottom: 22px; background: rgba(0,0,0,0.25); padding: 6px; border-radius: 999px; }
.tabs button {
  flex: 1;
  border: 0;
  background: transparent;
  color: var(--muted);
  font-size: 0.92rem;
  font-weight: 600;
  padding: 12px 8px;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
}
.tabs button[aria-selected="true"] { background: var(--amber); color: #1a1206; }
.field { margin-bottom: 18px; }
.field label { display: block; font-size: 0.9rem; color: var(--muted); margin-bottom: 8px; font-weight: 600; }
input[type="time"] {
  width: 100%;
  font-size: 1.5rem;
  padding: 14px 16px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(0, 0, 0, 0.3);
  color: var(--text);
  color-scheme: dark;
}
.btn {
  display: inline-block;
  width: 100%;
  border: 0;
  cursor: pointer;
  background: linear-gradient(135deg, var(--amber), #e09a1f);
  color: #1a1206;
  font-size: 1.05rem;
  font-weight: 700;
  padding: 15px;
  border-radius: 12px;
  transition: transform 0.15s, box-shadow 0.2s;
  box-shadow: 0 10px 30px rgba(246, 183, 60, 0.25);
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 14px 34px rgba(246, 183, 60, 0.35); }
.btn:active { transform: translateY(0); }

/* results */
.results { margin-top: 26px; display: none; }
.results.show { display: block; animation: fadeUp 0.45s ease; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.results h2 { font-family: var(--serif); font-weight: 500; font-size: 1.35rem; margin: 0 0 4px; }
.results .sub { color: var(--muted); font-size: 0.9rem; margin: 0 0 16px; }
.result-grid { display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); }
.result-card {
  background: rgba(0, 0, 0, 0.28);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px 12px;
  text-align: center;
  position: relative;
}
.result-card .time { font-size: 1.5rem; font-weight: 700; letter-spacing: 0.01em; }
.result-card .cycles { font-size: 0.8rem; color: var(--muted); margin-top: 4px; }
.result-card .hours { font-size: 0.78rem; color: var(--faint); }
.result-card.recommended { border-color: var(--amber); background: var(--amber-soft); }
.badge {
  position: absolute;
  top: -11px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--amber);
  color: #1a1206;
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 3px 12px;
  border-radius: 999px;
  white-space: nowrap;
}

/* content sections */
.content { padding: 36px 0; }
.content h2 { font-family: var(--serif); font-weight: 500; font-size: clamp(1.4rem, 3vw, 1.9rem); margin: 40px 0 14px; }
.content h2:first-child { margin-top: 0; }
.content h3 { font-size: 1.08rem; margin: 26px 0 8px; color: var(--text); }
.content p { color: var(--muted); margin: 0 0 14px; }
.content p strong, .content li strong { color: var(--text); }
.content ul, .content ol { color: var(--muted); padding-left: 22px; margin: 0 0 14px; }
.content li { margin-bottom: 8px; }
.tip-box {
  background: var(--amber-soft);
  border: 1px solid rgba(246, 183, 60, 0.35);
  border-radius: 14px;
  padding: 18px 20px;
  margin: 22px 0;
}
.tip-box p { margin: 0; color: var(--text); font-size: 0.95rem; }
.tip-box .kicker { color: var(--amber); font-weight: 700; font-size: 0.78rem; letter-spacing: 0.08em; text-transform: uppercase; display: block; margin-bottom: 6px; }

/* bedtime table */
.sleep-table { width: 100%; border-collapse: collapse; margin: 18px 0 8px; font-size: 0.95rem; }
.sleep-table th, .sleep-table td { padding: 13px 10px; text-align: left; border-bottom: 1px solid var(--border); }
.sleep-table th { color: var(--faint); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.07em; font-weight: 700; }
.sleep-table td.time { font-size: 1.25rem; font-weight: 700; }
.sleep-table tr.recommended td { color: var(--amber); }
.sleep-table tr.recommended td.time::after {
  content: "Recommended";
  font-size: 0.66rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--amber);
  color: #1a1206;
  border-radius: 999px;
  padding: 3px 10px;
  margin-left: 10px;
  vertical-align: middle;
}
.table-note { font-size: 0.82rem; color: var(--faint); margin: 0 0 18px; }

/* faq */
.faq { margin: 10px 0; border: 1px solid var(--border); border-radius: 14px; overflow: hidden; background: var(--surface); }
.faq + .faq { margin-top: 12px; }
.faq summary { cursor: pointer; padding: 16px 20px; font-weight: 600; list-style: none; display: flex; justify-content: space-between; align-items: center; gap: 12px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--amber); font-size: 1.4rem; font-weight: 400; flex: none; }
.faq[open] summary::after { content: "–"; }
.faq .a { padding: 0 20px 18px; color: var(--muted); font-size: 0.95rem; }
.faq .a p { margin: 0 0 10px; }

/* page links */
.page-links { display: grid; gap: 10px; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); margin: 18px 0; }
.page-links a {
  display: block;
  text-decoration: none;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px;
  font-size: 0.92rem;
  font-weight: 600;
  text-align: center;
  transition: border-color 0.2s, transform 0.15s;
}
.page-links a:hover { border-color: var(--amber); transform: translateY(-2px); }
.page-links a span { display: block; font-weight: 400; font-size: 0.78rem; color: var(--faint); margin-top: 2px; }
.pager { display: flex; justify-content: space-between; gap: 12px; margin: 34px 0 8px; }
.pager a {
  flex: 1;
  text-decoration: none;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  font-size: 0.9rem;
}
.pager a:hover { border-color: var(--amber); }
.pager .dir { display: block; font-size: 0.72rem; color: var(--faint); text-transform: uppercase; letter-spacing: 0.07em; margin-bottom: 2px; }

/* footer */
.site-footer { border-top: 1px solid var(--border); margin-top: 40px; padding: 34px 0 44px; }
.site-footer .cols { display: grid; gap: 26px; grid-template-columns: 1.4fr 1fr 1fr; }
.site-footer h4 { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--faint); margin: 0 0 12px; }
.site-footer a { color: var(--muted); text-decoration: none; font-size: 0.9rem; display: block; margin-bottom: 8px; }
.site-footer a:hover { color: var(--amber); }
.site-footer .fine { margin-top: 26px; font-size: 0.8rem; color: var(--faint); }
.site-footer .fine a { display: inline; font-size: 0.8rem; }

@media (max-width: 720px) {
  .site-footer .cols { grid-template-columns: 1fr 1fr; }
  .nav { display: none; }
  .hero { padding: 40px 0 20px; }
  .result-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 721px) {
  .menu-btn { display: none; }
}
.menu-btn {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 10px;
  padding: 8px 12px;
  font-size: 1.1rem;
  cursor: pointer;
}
.mobile-nav { display: none; border-top: 1px solid var(--border); padding: 10px 20px 16px; }
.mobile-nav.open { display: block; }
.mobile-nav a { display: block; color: var(--muted); text-decoration: none; padding: 10px 4px; border-bottom: 1px solid rgba(255,255,255,0.05); font-size: 0.95rem; }