/* ============================================================
   FROSTWATCH — design tokens for the Bear Trap Eligibility Calculator
   Concept: arctic survival outpost console. Ice-blue surfaces,
   glacial neutrals, amber for cooldown, teal-green for eligible.
   ============================================================ */

:root {
  /* Fluid type scale */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.25rem);
  --text-3xl: clamp(2.25rem, 1rem + 3.6vw, 4.25rem);

  /* Spacing (4px base) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  --radius-sm: 0.375rem;
  --radius-md: 0.625rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 9999px;

  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  --content-narrow: 640px;
  --content-default: 880px;
  --content-wide: 1180px;

  --font-display: 'Cabinet Grotesk', 'Segoe UI', sans-serif;
  --font-body: 'Satoshi', 'Helvetica Neue', sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
}

/* ---------- LIGHT MODE (default) ---------- */
:root,
[data-theme='light'] {
  --color-bg: #eef4f7;
  --color-surface: #ffffff;
  --color-surface-2: #f6fafc;
  --color-surface-offset: #e4edf2;
  --color-divider: #d3e2e9;
  --color-border: #c3d7e0;

  --color-text: #0e2430;
  --color-text-muted: #4c6b78;
  --color-text-faint: #93aab3;
  --color-text-inverse: #f4fafc;

  /* Frost teal — primary accent */
  --color-primary: #0e7c86;
  --color-primary-hover: #0a626b;
  --color-primary-active: #084f56;
  --color-primary-highlight: #d3ecee;

  /* Amber — cooldown / warning */
  --color-warning: #c3720d;
  --color-warning-hover: #a25c08;
  --color-warning-active: #7c4706;
  --color-warning-highlight: #f7e3c4;

  /* Green — eligible / success */
  --color-success: #1f8a4c;
  --color-success-hover: #176e3c;
  --color-success-active: #12552e;
  --color-success-highlight: #d3ecdb;

  --color-error: #b0304a;
  --color-error-highlight: #f2d6dc;

  --shadow-sm: 0 1px 2px oklch(0.3 0.03 220 / 0.08);
  --shadow-md: 0 8px 24px oklch(0.3 0.03 220 / 0.1);
  --shadow-lg: 0 20px 48px oklch(0.3 0.03 220 / 0.14);

  --grid-line: color-mix(in oklab, var(--color-primary) 8%, transparent);
}

/* ---------- DARK MODE ---------- */
[data-theme='dark'] {
  --color-bg: #0a1620;
  --color-surface: #101f2c;
  --color-surface-2: #142633;
  --color-surface-offset: #162936;
  --color-divider: #223b49;
  --color-border: #274456;

  --color-text: #dbeaf0;
  --color-text-muted: #8ba8b5;
  --color-text-faint: #547080;
  --color-text-inverse: #0a1620;

  --color-primary: #4fc3cf;
  --color-primary-hover: #6fd4de;
  --color-primary-active: #8adfe7;
  --color-primary-highlight: #17363b;

  --color-warning: #f0a844;
  --color-warning-hover: #f5bc6c;
  --color-warning-active: #f8ce93;
  --color-warning-highlight: #3c2e18;

  --color-success: #4fcb82;
  --color-success-hover: #74d89e;
  --color-success-active: #9ae4ba;
  --color-success-highlight: #163a26;

  --color-error: #e0708a;
  --color-error-highlight: #3a1e26;

  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.3);
  --shadow-md: 0 8px 24px oklch(0 0 0 / 0.35);
  --shadow-lg: 0 20px 48px oklch(0 0 0 / 0.45);

  --grid-line: color-mix(in oklab, var(--color-primary) 10%, transparent);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #0a1620;
    --color-surface: #101f2c;
    --color-surface-2: #142633;
    --color-surface-offset: #162936;
    --color-divider: #223b49;
    --color-border: #274456;
    --color-text: #dbeaf0;
    --color-text-muted: #8ba8b5;
    --color-text-faint: #547080;
    --color-text-inverse: #0a1620;
    --color-primary: #4fc3cf;
    --color-primary-hover: #6fd4de;
    --color-primary-active: #8adfe7;
    --color-primary-highlight: #17363b;
    --color-warning: #f0a844;
    --color-warning-hover: #f5bc6c;
    --color-warning-active: #f8ce93;
    --color-warning-highlight: #3c2e18;
    --color-success: #4fcb82;
    --color-success-hover: #74d89e;
    --color-success-active: #9ae4ba;
    --color-success-highlight: #163a26;
    --color-error: #e0708a;
    --color-error-highlight: #3a1e26;
    --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.3);
    --shadow-md: 0 8px 24px oklch(0 0 0 / 0.35);
    --shadow-lg: 0 20px 48px oklch(0 0 0 / 0.45);
    --grid-line: color-mix(in oklab, var(--color-primary) 10%, transparent);
  }
}

body {
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 48px 48px;
  background-attachment: fixed;
}

/* ============================================================
   LAYOUT
   ============================================================ */

.wrap {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--color-primary);
  color: var(--color-text-inverse);
  padding: var(--space-3) var(--space-4);
  z-index: 100;
  border-radius: var(--radius-sm);
}
.skip-link:focus {
  left: var(--space-4);
  top: var(--space-4);
}

/* ---------- Header ---------- */
.site-header {
  padding-block: var(--space-6);
  border-bottom: 1px solid var(--color-divider);
  background: color-mix(in oklab, var(--color-surface) 88%, transparent);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 20;
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}
.brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text);
}
.brand svg {
  width: 38px;
  height: 38px;
  color: var(--color-primary);
  flex-shrink: 0;
}
.brand-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-lg);
  letter-spacing: -0.01em;
  line-height: 1.1;
}
.brand-tag {
  display: block;
  font-family: var(--font-body);
  font-weight: 500;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-surface-2);
  color: var(--color-text);
}
.theme-toggle:hover {
  background: var(--color-surface-offset);
  border-color: var(--color-primary);
}
.theme-toggle svg {
  width: 18px;
  height: 18px;
}

/* ---------- Hero ---------- */
.hero {
  padding-block: var(--space-16) var(--space-10);
  overflow: hidden;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  align-items: center;
  gap: var(--space-8);
}
@media (min-width: 900px) {
  .hero-grid {
    grid-template-columns: 1.2fr 0.8fr;
    gap: var(--space-12);
  }
}
.hero-illustration {
  display: flex;
  justify-content: center;
  order: -1;
}
@media (min-width: 900px) {
  .hero-illustration {
    order: 0;
    justify-content: flex-end;
  }
}
.hero-illustration img {
  width: 100%;
  max-width: 340px;
  height: auto;
  filter: drop-shadow(0 16px 32px oklch(0.3 0.05 220 / 0.18));
}
@media (min-width: 900px) {
  .hero-illustration img {
    max-width: 400px;
  }
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: var(--color-primary-highlight);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-5);
}
.eyebrow svg {
  width: 14px;
  height: 14px;
}
.hero h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-2xl);
  letter-spacing: -0.015em;
  max-width: 16ch;
  margin-bottom: var(--space-5);
}
.hero p.lede {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 62ch;
  font-weight: 400;
}

/* ---------- Section shells ---------- */
main {
  padding-bottom: var(--space-24);
}
.section {
  padding-block: var(--space-12);
}
.section-head {
  margin-bottom: var(--space-8);
}
.section-kicker {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin-bottom: var(--space-2);
}
.section h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-xl);
  letter-spacing: -0.01em;
}

/* ============================================================
   CALCULATOR CARD
   ============================================================ */
.calc-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.calc-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}
@media (min-width: 860px) {
  .calc-grid {
    grid-template-columns: 1.05fr 1fr;
  }
  .calc-inputs {
    border-right: 1px solid var(--color-divider);
  }
}

.calc-inputs,
.calc-result {
  padding: var(--space-8);
}

.calc-inputs h3,
.calc-result h3 {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 700;
  margin-bottom: var(--space-5);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.result-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-3);
  flex-wrap: wrap;
}
.result-head h3 {
  margin-bottom: 0;
}
.mode-toggle-sm {
  margin-bottom: var(--space-5);
  padding: 3px;
}
.mode-toggle-sm button {
  min-width: 64px;
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
}
.calc-inputs h3 svg,
.calc-result h3 svg {
  width: 18px;
  height: 18px;
  color: var(--color-primary);
}

/* Segmented toggle: Local vs UTC */
.mode-toggle {
  display: inline-flex;
  background: var(--color-surface-offset);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: var(--space-1);
  gap: var(--space-1);
  margin-bottom: var(--space-6);
}
.mode-toggle button {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  padding: var(--space-2) var(--space-5);
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  min-width: 100px;
}
.mode-toggle button[aria-pressed='true'] {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-sm);
}
.mode-toggle button:not([aria-pressed='true']):hover {
  color: var(--color-text);
}

.input-hint {
  display: flex;
  align-items: flex-start;
  gap: var(--space-2);
  background: var(--color-warning-highlight);
  color: var(--color-warning-active, var(--color-warning));
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-xs);
  line-height: 1.5;
  margin-bottom: var(--space-6);
}
.input-hint svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  margin-top: 1px;
}
.input-hint strong {
  font-weight: 700;
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  margin-bottom: var(--space-5);
}
.field {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.field label {
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-text-muted);
  letter-spacing: 0.03em;
  text-transform: uppercase;
}
.field input {
  border: 1px solid var(--color-border);
  background: var(--color-surface-2);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  font-family: var(--font-mono);
  color: var(--color-text);
  width: 100%;
}
.field input:focus-visible {
  border-color: var(--color-primary);
  background: var(--color-surface);
}

.tz-note {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-bottom: var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.tz-note svg {
  width: 13px;
  height: 13px;
  flex-shrink: 0;
}

.btn-row {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
}
.btn {
  font-family: var(--font-body);
  font-weight: 600;
  font-size: var(--text-sm);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}
.btn svg {
  width: 15px;
  height: 15px;
}
.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}
.btn-primary:hover {
  background: var(--color-primary-hover);
}
.btn-ghost {
  background: var(--color-surface-offset);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}
.btn-ghost:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ---------- Result panel ---------- */
.calc-result {
  background: var(--color-surface-2);
  display: flex;
  flex-direction: column;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-5);
  width: fit-content;
}
.status-badge.is-cooldown {
  background: var(--color-warning-highlight);
  color: var(--color-warning-active, var(--color-warning));
}
.status-badge.is-eligible {
  background: var(--color-success-highlight);
  color: var(--color-success-active, var(--color-success));
}
.status-badge .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: currentColor;
}

.result-label {
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-faint);
  margin-bottom: var(--space-2);
}
.result-utc {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-1);
  word-break: break-word;
}
.result-local {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}

.countdown {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-2);
  margin-bottom: var(--space-6);
}
.countdown .unit {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-2);
  text-align: center;
}
.countdown .unit .num {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--color-primary);
  display: block;
}
.countdown .unit .lbl {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.result-footnote {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: auto;
  padding-top: var(--space-4);
  border-top: 1px dashed var(--color-divider);
}

/* ============================================================
   RULE EXPLANATION
   ============================================================ */
.rule-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-sm);
}
.rule-card > p {
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
  font-size: var(--text-base);
}
.rule-card strong {
  color: var(--color-text);
}

.timeline {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}
.timeline .step {
  background: var(--color-surface-2);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  position: relative;
}
.timeline .step .step-index {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-bottom: var(--space-2);
}
.timeline .step h4 {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  margin-bottom: var(--space-2);
}
.timeline .step p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}
.timeline .step.accent {
  border-color: var(--color-primary);
  background: var(--color-primary-highlight);
}
.timeline .step.accent h4 {
  color: var(--color-primary-active, var(--color-primary));
}

.example-box {
  background: var(--color-surface-offset);
  border-radius: var(--radius-lg);
  padding: var(--space-5) var(--space-6);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  border-left: 3px solid var(--color-primary);
}
.example-box strong {
  color: var(--color-text);
}

/* ---------- FAQ ---------- */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}
.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: var(--space-5) var(--space-6);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-base);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}
.faq-item summary::-webkit-details-marker {
  display: none;
}
.faq-item summary .chev {
  width: 18px;
  height: 18px;
  color: var(--color-text-faint);
  flex-shrink: 0;
  transition: transform var(--transition-interactive);
}
.faq-item[open] summary .chev {
  transform: rotate(180deg);
}
.faq-item .faq-body {
  padding: 0 var(--space-6) var(--space-6);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* ---------- Footer ---------- */
.site-footer {
  padding-block: var(--space-10);
  border-top: 1px solid var(--color-divider);
}
.site-footer .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-4);
  align-items: center;
}
.site-footer p {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}
.credit-note {
  width: 100%;
  text-align: center;
  padding-top: var(--space-4);
  margin-top: var(--space-2);
  border-top: 1px dashed var(--color-divider);
  letter-spacing: 0.02em;
}
.site-footer a {
  color: var(--color-primary);
  text-decoration: none;
}
.site-footer a:hover {
  text-decoration: underline;
}

/* ---------- Responsive ---------- */
@media (max-width: 859px) {
  .timeline {
    grid-template-columns: 1fr;
  }
  .countdown {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 480px) {
  .field-row {
    grid-template-columns: 1fr;
  }
  .hero h1 {
    max-width: none;
  }
}