:root {
  --bg-0: #0f1421;
  --bg-1: #161c2c;
  --card: #1c2238;
  --card-2: #232b48;
  --border: #2c3454;
  --text: #e8ecf4;
  --muted: #98a3bf;
  --accent: #6f95ee;       /* moonlight blue */
  --accent-2: #bf94f0;     /* violet */
  --gold: #e6c46c;
  --rem: #d36a86;
  --sws: #6f95ee;
  --n12: #98a3bf;
  --wake: #444a5a;
  --good: #4cd0a0;
  --warn: #e6a04c;
  --bad: #f06464;
  --caf: #d36a86;
  --alc: #e6c46c;
  --ex: #4cd0a0;
  --meal: #f5a37b;
  --light: #f0e3a8;
  --sleep: #6f95ee;
  --cbtmin: #98a3bf;
  --dlmo: #bf94f0;
  --shadow: 0 6px 28px rgba(0,0,0,0.35);
  --radius: 14px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--bg-0);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto,
    "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

.bg {
  position: fixed; inset: 0; pointer-events: none; z-index: 0;
  background:
    radial-gradient(900px 600px at 80% -10%, rgba(111,149,238,0.16), transparent 60%),
    radial-gradient(600px 400px at 10% 110%, rgba(191,148,240,0.12), transparent 60%);
}

header, nav.tabs, main, footer { position: relative; z-index: 1; }

header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 1.2rem 2rem 0.6rem 2rem;
}

.brand { display: flex; align-items: center; gap: 0.8rem; }
.logo-dot {
  width: 36px; height: 36px; border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, var(--accent-2), var(--accent) 60%, #1a3060 100%);
  box-shadow: 0 0 24px rgba(191,148,240,0.45);
}
.brand-text .logo {
  font-size: 1.25rem; font-weight: 700; letter-spacing: -0.01em;
  color: var(--text);
}
.brand-text .tagline { font-size: 0.82rem; color: var(--muted); }

.meta { font-size: 0.8rem; color: var(--muted); }

nav.tabs {
  display: flex; gap: 0.4rem; flex-wrap: wrap;
  padding: 0 2rem; border-bottom: 1px solid var(--border);
}
.tab {
  background: none; border: none; padding: 0.7rem 1.1rem;
  cursor: pointer; font: inherit; color: var(--muted);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px; transition: all 0.15s;
}
.tab:hover { color: var(--text); }
.tab.active {
  color: var(--accent-2); border-bottom-color: var(--accent-2);
  font-weight: 600;
}

main {
  padding: 1.4rem 2rem 3rem 2rem;
  max-width: 1400px; margin: 0 auto;
}
.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fadeIn 0.25s; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.grid-2col {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem;
}
.span-2 { grid-column: 1 / -1; }

@media (max-width: 900px) {
  .grid-2col { grid-template-columns: 1fr; }
  header { padding: 1rem; }
  nav.tabs { padding: 0 0.6rem; overflow-x: auto; }
  main { padding: 1rem; }
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.4rem;
  box-shadow: var(--shadow);
}
.card h2 {
  margin: 0 0 0.6rem 0;
  font-size: 1.05rem; font-weight: 600;
  letter-spacing: -0.005em;
}
.card h3 {
  margin: 1.1rem 0 0.4rem 0;
  font-size: 0.92rem; color: var(--muted);
  text-transform: uppercase; letter-spacing: 0.06em;
}

.row { display: flex; gap: 0.7rem; margin: 0.55rem 0; flex-wrap: wrap; align-items: end; }
.row.two-up > label { flex: 1 1 45%; }

label {
  display: flex; flex-direction: column; gap: 0.2rem;
  font-size: 0.82rem; color: var(--muted); min-width: 0;
  width: 100%;
}
label input, label select {
  font: inherit; font-size: 0.95rem; padding: 0.5rem 0.6rem;
  border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg-1); color: var(--text);
  width: 100%;
}
label input[type="range"] { padding: 0; height: 30px; background: transparent; }

input[type="range"] { -webkit-appearance: none; appearance: none; outline: none; }
input[type="range"]::-webkit-slider-runnable-track {
  height: 4px; background: var(--bg-1); border-radius: 4px;
}
input[type="range"]::-moz-range-track {
  height: 4px; background: var(--bg-1); border-radius: 4px;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--accent-2); margin-top: -7px;
  box-shadow: 0 0 0 4px rgba(191,148,240,0.18);
  cursor: pointer;
}
input[type="range"]::-moz-range-thumb {
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--accent-2); border: none;
  box-shadow: 0 0 0 4px rgba(191,148,240,0.18);
  cursor: pointer;
}
.readout { font-size: 0.82rem; color: var(--text); margin-top: 0.2rem; }

label.checkbox-row {
  flex-direction: row; align-items: center; gap: 0.5rem;
  color: var(--text);
}
label.checkbox-row input { width: auto; }

button {
  font: inherit; padding: 0.55rem 1rem;
  border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg-1); color: var(--text); cursor: pointer;
  transition: all 0.12s;
}
button:hover { border-color: var(--accent-2); color: var(--text); }
button.primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: white; border-color: transparent; font-weight: 600;
  box-shadow: 0 6px 18px rgba(111,149,238,0.35);
}
button.primary:hover { transform: translateY(-1px); }
button.ghost { background: transparent; color: var(--muted); }
button.small { font-size: 0.85rem; padding: 0.4rem 0.7rem; }
button.big { padding: 0.7rem 1.4rem; font-size: 1rem; }

.cta-card {
  display: flex; flex-direction: row; align-items: center; gap: 0.6rem;
  justify-content: flex-start;
}

/* Caffeine / alcohol / exercise rows */
.item-row {
  display: grid; gap: 0.4rem; margin: 0.3rem 0;
  grid-template-columns: 1fr 1fr 36px;
  align-items: end;
}
.item-row.three { grid-template-columns: 1fr 1fr 1fr 36px; }
.item-row .remove-btn {
  background: transparent; border: 1px solid var(--border); color: var(--muted);
  height: 38px; padding: 0;
}
.item-row .remove-btn:hover { border-color: var(--bad); color: var(--bad); }

/* Score ring */
.score-ring { position: relative; width: 200px; height: 200px; margin: 0.6rem auto; }
.score-ring svg { width: 100%; height: 100%; }
.score-center {
  position: absolute; inset: 0;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
}
.score-value {
  font-size: 3.2rem; font-weight: 700; line-height: 1; color: var(--text);
  background: linear-gradient(180deg, var(--text), var(--accent-2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.score-label { color: var(--muted); font-size: 0.85rem; }

.interpretation {
  text-align: center; color: var(--muted); margin-top: 0.6rem;
  font-size: 0.95rem;
}

.hero-card { background: linear-gradient(160deg, var(--card-2), var(--card)); }

/* Metric grid */
.metric-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.7rem;
}
@media (max-width: 700px) { .metric-grid { grid-template-columns: repeat(2, 1fr); } }
.metric { background: var(--bg-1); border-radius: 10px; padding: 0.7rem 0.9rem; }
.metric-value {
  font-size: 1.25rem; font-weight: 700; color: var(--text);
  font-variant-numeric: tabular-nums;
}
.metric-label { font-size: 0.78rem; color: var(--muted); margin-top: 0.2rem; }

/* Canvas + legends */
canvas {
  display: block; width: 100%;
  background: var(--bg-1); border-radius: 10px;
  margin: 0.4rem 0;
}

.chart-legend {
  display: flex; gap: 1rem; flex-wrap: wrap;
  font-size: 0.82rem; color: var(--muted); margin-top: 0.3rem;
}
.chart-legend .dot {
  display: inline-block; width: 0.6rem; height: 0.6rem;
  border-radius: 50%; margin-right: 0.3rem; vertical-align: middle;
}
.chart-legend .wake     { background: var(--wake); }
.chart-legend .rem      { background: var(--rem); }
.chart-legend .n12      { background: var(--n12); }
.chart-legend .sws      { background: var(--sws); }
.chart-legend .processS { background: var(--accent-2); }
.chart-legend .upperT   { background: var(--gold); }
.chart-legend .lowerT   { background: var(--n12); }
.chart-legend .alert    { background: var(--accent); }
.chart-legend .kss      { background: var(--gold); }
.chart-legend .sleep-band { background: rgba(111,149,238,0.3); }

/* Clock card */
.clock-card canvas { aspect-ratio: 1 / 1; max-width: 600px; margin: 0 auto; background: transparent; }

.legend-list { padding: 0; list-style: none; margin: 0; }
.legend-list li {
  font-size: 0.92rem; color: var(--text); margin: 0.45rem 0;
  display: flex; align-items: center; gap: 0.55rem;
}
.legend-swatch {
  display: inline-block; width: 14px; height: 14px; border-radius: 50%;
}
.legend-swatch.caf    { background: var(--caf); }
.legend-swatch.alc    { background: var(--alc); }
.legend-swatch.ex     { background: var(--ex); }
.legend-swatch.meal   { background: var(--meal); }
.legend-swatch.light  { background: var(--light); }
.legend-swatch.sleep  { background: var(--sleep); }
.legend-swatch.cbtmin { background: var(--cbtmin); }
.legend-swatch.dlmo   { background: var(--dlmo); }

.hint { font-size: 0.86rem; color: var(--muted); margin: 0.2rem 0 0.6rem 0; }

/* Optimize table */
.opt-table { width: 100%; border-collapse: collapse; }
.opt-table th, .opt-table td {
  text-align: left; padding: 0.6rem 0.8rem;
  border-bottom: 1px solid var(--border);
}
.opt-table th {
  font-size: 0.74rem; color: var(--muted);
  text-transform: uppercase; letter-spacing: 0.06em; font-weight: 600;
}
.opt-table .delta { color: var(--good); font-weight: 600; font-variant-numeric: tabular-nums; }
.opt-table .delta.zero { color: var(--muted); font-weight: normal; }
.opt-table .delta.neg { color: var(--bad); }
.opt-table .iname { color: var(--text); font-weight: 600; }
.opt-table .idesc { color: var(--muted); font-size: 0.82rem; margin-top: 0.15rem; }

footer {
  padding: 1rem 2rem 2rem 2rem;
  color: var(--muted); font-size: 0.82rem;
  max-width: 1400px; margin: 0 auto;
  text-align: center;
}