:root {
  --dark-teal: #243832;
  --dark-bg: #1a2e28;
  --darker-bg: #142420;
  --gold: #C9A96E;
  --cream: #F0EDE6;
  --cream-muted: #8a9a94;
  --green: #4CAF50;
  --yellow: #C9A96E;
  --red: #E57373;
  --card-bg: #1e3a33;
  --card-border: #2d4f46;
}

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

html {
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  background: var(--darker-bg);
  color: var(--cream);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* Header */
.header {
  background: var(--dark-bg);
  border-bottom: 1px solid var(--card-border);
  padding: 1rem 1.25rem;
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-inner {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.625rem;
}

.brand-mark {
  width: 2rem;
  height: 2rem;
  background: var(--gold);
  border-radius: 0.375rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.875rem;
  color: var(--dark-teal);
}

.brand h1 {
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.brand h1 span {
  color: var(--gold);
}

#date {
  font-size: 0.75rem;
  color: var(--cream-muted);
}

#demo-badge {
  display: none;
  background: var(--gold);
  color: var(--dark-teal);
  font-size: 0.625rem;
  font-weight: 700;
  padding: 0.125rem 0.5rem;
  border-radius: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Main */
main {
  max-width: 800px;
  margin: 0 auto;
  padding: 1rem 1.25rem 2rem;
}

/* Metrics Grid */
#metrics {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.875rem;
}

/* Cards */
.metric-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 0.75rem;
  padding: 1.25rem;
}

.primary-card {
  border-color: var(--gold);
  border-width: 1px;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.card-header h2 {
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--cream-muted);
}

/* Zone Badges */
.zone-badge {
  font-size: 0.6875rem;
  font-weight: 600;
  padding: 0.1875rem 0.625rem;
  border-radius: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.zone-green {
  background: rgba(76, 175, 80, 0.15);
  color: var(--green);
}

.zone-yellow {
  background: rgba(201, 169, 110, 0.15);
  color: var(--yellow);
}

.zone-red {
  background: rgba(229, 115, 115, 0.15);
  color: var(--red);
}

/* Gauge */
.gauge {
  display: flex;
  justify-content: center;
  margin: 0.5rem 0;
}

.gauge svg {
  width: 120px;
  height: 120px;
}

.gauge-value {
  font-size: 1.75rem;
  font-weight: 700;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, monospace;
}

.gauge-unit {
  font-size: 0.75rem;
  font-weight: 400;
}

/* Metric Values */
.metric-value {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--cream);
  text-align: center;
  margin: 0.5rem 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, monospace;
}

.metric-unit {
  font-size: 1rem;
  font-weight: 400;
  color: var(--cream-muted);
  margin-left: 0.25rem;
}

.metric-subtitle {
  font-size: 0.75rem;
  color: var(--cream-muted);
  text-align: center;
}

/* Sleep / Strain Details */
.sleep-details,
.strain-details {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--card-border);
}

.sleep-detail {
  display: flex;
  flex-direction: column;
  gap: 0.125rem;
}

.detail-label {
  font-size: 0.6875rem;
  color: var(--cream-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.detail-value {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--cream);
}

/* Loading */
.loading {
  grid-column: 1 / -1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding: 3rem;
  color: var(--cream-muted);
}

.loading-spinner {
  width: 2rem;
  height: 2rem;
  border: 3px solid var(--card-border);
  border-top-color: var(--gold);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Error */
.error-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: 3rem;
  color: var(--cream-muted);
}

.error-state button {
  margin-top: 1rem;
  padding: 0.5rem 1.5rem;
  background: var(--gold);
  color: var(--dark-teal);
  border: none;
  border-radius: 0.375rem;
  font-weight: 600;
  cursor: pointer;
}

.error-state button:hover {
  opacity: 0.9;
}

/* Tablet: 2-column */
@media (min-width: 600px) {
  #metrics {
    grid-template-columns: 1fr 1fr;
  }

  .primary-card {
    grid-column: 1 / -1;
  }

  .metric-card:last-child:nth-child(odd) {
    grid-column: 1 / -1;
  }
}

/* Desktop tweaks */
@media (min-width: 900px) {
  .header {
    padding: 1.25rem 2rem;
  }

  main {
    padding: 1.5rem 2rem 3rem;
  }

  .gauge svg {
    width: 140px;
    height: 140px;
  }
}