/*
 * SunSafe Timer — Main Stylesheet
 * Art direction: Health/wellness tool → clean, precise, calming with warm-sun accents
 * Palette: Nexus warm beige surfaces + amber/gold sun accent + teal primary
 * Typography: Instrument Serif (display) + Work Sans (body)
 * Density: Balanced — clear data cards with comfortable breathing room
 */

/* ====================================================================
   1. DESIGN TOKENS
   ==================================================================== */
: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,  3.5rem);

  /* 4px spacing scale */
  --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;

  /* Content widths */
  --content-narrow:  640px;
  --content-default: 960px;
  --content-wide:    1200px;

  /* Radius */
  --radius-sm:   0.375rem;
  --radius-md:   0.5rem;
  --radius-lg:   0.75rem;
  --radius-xl:   1rem;
  --radius-full: 9999px;

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

  /* Fonts */
  --font-display: 'Instrument Serif', Georgia, serif;
  --font-body:    'Work Sans', 'Helvetica Neue', sans-serif;
}

/* Light mode (Nexus palette + sun amber accent) */
:root, [data-theme="light"] {
  --color-bg:               #f7f6f2;
  --color-surface:          #f9f8f5;
  --color-surface-2:        #fbfbf9;
  --color-surface-offset:   #f3f0ec;
  --color-surface-offset-2: #edeae5;
  --color-surface-dynamic:  #e6e4df;
  --color-divider:          #dcd9d5;
  --color-border:           #d4d1ca;

  --color-text:         #28251d;
  --color-text-muted:   #7a7974;
  --color-text-faint:   #bab9b4;
  --color-text-inverse: #f9f8f4;

  /* Primary teal — actions, links */
  --color-primary:           #01696f;
  --color-primary-hover:     #0c4e54;
  --color-primary-active:    #0f3638;
  --color-primary-highlight: #cedcd8;

  /* Sun accent — amber/gold for UV / sun elements */
  --color-sun:            #d48800;
  --color-sun-hover:      #b56c00;
  --color-sun-highlight:  #f7e8c8;
  --color-sun-text:       #7a4700;

  /* Risk level colours */
  --color-risk-low:       #437a22;
  --color-risk-moderate:  #d19900;
  --color-risk-high:      #da7101;
  --color-risk-very-high: #a12c7b;
  --color-risk-extreme:   #a13544;

  /* Semantic */
  --color-success:  #437a22;
  --color-warning:  #da7101;
  --color-error:    #a13544;
  --color-info:     #006494;

  /* Shadows */
  --shadow-sm: 0 1px 2px oklch(0.2 0.01 80 / 0.06);
  --shadow-md: 0 4px 12px oklch(0.2 0.01 80 / 0.08);
  --shadow-lg: 0 12px 32px oklch(0.2 0.01 80 / 0.12);
}

/* Dark mode */
[data-theme="dark"],
@media (prefers-color-scheme: dark) { :root:not([data-theme]) {
  --color-bg:               #171614;
  --color-surface:          #1c1b19;
  --color-surface-2:        #201f1d;
  --color-surface-offset:   #1d1c1a;
  --color-surface-offset-2: #22211f;
  --color-surface-dynamic:  #2d2c2a;
  --color-divider:          #262523;
  --color-border:           #393836;

  --color-text:         #cdccca;
  --color-text-muted:   #797876;
  --color-text-faint:   #5a5957;
  --color-text-inverse: #2b2a28;

  --color-primary:           #4f98a3;
  --color-primary-hover:     #227f8b;
  --color-primary-active:    #1a626b;
  --color-primary-highlight: #313b3b;

  --color-sun:            #f0a928;
  --color-sun-hover:      #d98c00;
  --color-sun-highlight:  #3a3020;
  --color-sun-text:       #f0a928;

  --color-risk-low:       #6daa45;
  --color-risk-moderate:  #e8af34;
  --color-risk-high:      #fdab43;
  --color-risk-very-high: #d163a7;
  --color-risk-extreme:   #dd6974;

  --color-success:  #6daa45;
  --color-warning:  #fdab43;
  --color-error:    #dd6974;
  --color-info:     #5591c7;

  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.2);
  --shadow-md: 0 4px 12px oklch(0 0 0 / 0.3);
  --shadow-lg: 0 12px 32px oklch(0 0 0 / 0.4);
}}

[data-theme="dark"] {
  --color-bg:               #171614;
  --color-surface:          #1c1b19;
  --color-surface-2:        #201f1d;
  --color-surface-offset:   #1d1c1a;
  --color-surface-offset-2: #22211f;
  --color-surface-dynamic:  #2d2c2a;
  --color-divider:          #262523;
  --color-border:           #393836;
  --color-text:         #cdccca;
  --color-text-muted:   #797876;
  --color-text-faint:   #5a5957;
  --color-text-inverse: #2b2a28;
  --color-primary:           #4f98a3;
  --color-primary-hover:     #227f8b;
  --color-primary-active:    #1a626b;
  --color-primary-highlight: #313b3b;
  --color-sun:            #f0a928;
  --color-sun-hover:      #d98c00;
  --color-sun-highlight:  #3a3020;
  --color-sun-text:       #f0a928;
  --color-risk-low:       #6daa45;
  --color-risk-moderate:  #e8af34;
  --color-risk-high:      #fdab43;
  --color-risk-very-high: #d163a7;
  --color-risk-extreme:   #dd6974;
  --color-success:  #6daa45;
  --color-warning:  #fdab43;
  --color-error:    #dd6974;
  --color-info:     #5591c7;
  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.2);
  --shadow-md: 0 4px 12px oklch(0 0 0 / 0.3);
  --shadow-lg: 0 12px 32px oklch(0 0 0 / 0.4);
}

/* ====================================================================
   2. BASE RESET
   ==================================================================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-16);
}

body {
  min-height: 100dvh;
  line-height: 1.6;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  display: flex;
  flex-direction: column;
}

img, picture, video, canvas, svg { display: block; max-width: 100%; height: auto; }
ul[role="list"], ol[role="list"] { list-style: none; }
input, button, textarea, select { font: inherit; color: inherit; }
h1, h2, h3, h4, h5, h6 { text-wrap: balance; line-height: 1.2; }
p, li, figcaption { text-wrap: pretty; }

::selection { background: oklch(from var(--color-primary) l c h / 0.25); }

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

button { cursor: pointer; background: none; border: none; }
table  { border-collapse: collapse; width: 100%; }

a, button, [role="button"], input, textarea, select {
  transition: color var(--transition-interactive),
              background var(--transition-interactive),
              border-color var(--transition-interactive),
              box-shadow var(--transition-interactive);
}

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border-width: 0;
}

/* ====================================================================
   3. LAYOUT
   ==================================================================== */
.container {
  max-width: var(--content-default);
  margin-inline: auto;
  padding-inline: var(--space-4);
}
.container--wide {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-4);
}
.container--narrow {
  max-width: var(--content-narrow);
  margin-inline: auto;
  padding-inline: var(--space-4);
}

main { flex: 1; }

/* ====================================================================
   4. NAVIGATION
   ==================================================================== */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding-block: var(--space-3);
}

.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--color-text);
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;
  white-space: nowrap;
}
.site-logo svg { flex-shrink: 0; }

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  list-style: none;
}

.nav-links a {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  text-decoration: none;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
}
.nav-links a:hover,
.nav-links a.active { color: var(--color-primary); background: var(--color-primary-highlight); }

.nav-actions { display: flex; align-items: center; gap: var(--space-2); }

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  background: transparent;
}
.theme-toggle:hover { color: var(--color-primary); border-color: var(--color-primary); }

/* Mobile nav */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
  background: transparent;
  border: none;
  cursor: pointer;
}
.nav-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--color-text-muted);
  border-radius: 2px;
  transition: transform var(--transition-interactive), opacity var(--transition-interactive);
}

@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    flex-direction: column;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-4);
    gap: var(--space-2);
    box-shadow: var(--shadow-md);
  }
  .nav-links.open { display: flex; }
  .nav-links a { width: 100%; }
}

/* ====================================================================
   5. HERO / PAGE HEADER
   ==================================================================== */
.page-hero {
  background: linear-gradient(135deg,
    var(--color-sun-highlight) 0%,
    var(--color-primary-highlight) 60%,
    var(--color-surface) 100%);
  padding-block: clamp(var(--space-8), 5vw, var(--space-16));
  border-bottom: 1px solid var(--color-border);
}

.page-hero h1 {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  color: var(--color-text);
}
.page-hero .subtitle {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
  max-width: 60ch;
}

/* ====================================================================
   6. SECTION SPACING
   ==================================================================== */
.section { padding-block: clamp(var(--space-8), 4vw, var(--space-12)); }
.section + .section { border-top: 1px solid var(--color-divider); }

.section-heading {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* ====================================================================
   7. CARDS
   ==================================================================== */
.card {
  background: var(--color-surface);
  border: 1px solid oklch(from var(--color-text) l c h / 0.10);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}
.card--elevated {
  box-shadow: var(--shadow-md);
}

.card-title {
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}
.card-value {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-text);
  line-height: 1;
}
.card-unit {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

/* Result cards grid */
.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(220px, 100%), 1fr));
  gap: var(--space-4);
}

/* ====================================================================
   8. FORM ELEMENTS
   ==================================================================== */
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-label {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
}
.form-label .hint {
  font-weight: 400;
  color: var(--color-text-muted);
  margin-left: var(--space-1);
}

.form-input,
.form-select {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  color: var(--color-text);
  transition: border-color var(--transition-interactive),
              box-shadow var(--transition-interactive);
}
.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px oklch(from var(--color-primary) l c h / 0.15);
}
.form-input::placeholder { color: var(--color-text-faint); }

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(280px, 100%), 1fr));
  gap: var(--space-6);
}

/* Skin type selector */
.skin-type-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: var(--space-2);
}
@media (max-width: 480px) {
  .skin-type-grid { grid-template-columns: repeat(3, 1fr); }
}

.skin-type-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-3) var(--space-2);
  background: var(--color-surface-2);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  font-size: var(--text-xs);
  font-weight: 600;
  text-align: center;
  transition: all var(--transition-interactive);
  color: var(--color-text-muted);
  min-height: 44px;
}
.skin-type-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-highlight);
}
.skin-type-btn.selected {
  border-color: var(--color-primary);
  background: var(--color-primary-highlight);
  color: var(--color-primary);
  box-shadow: 0 0 0 1px var(--color-primary);
}

.skin-swatch {
  width: 28px; height: 28px;
  border-radius: var(--radius-full);
  border: 1px solid oklch(from var(--color-text) l c h / 0.15);
  flex-shrink: 0;
}
.swatch-1 { background: #f8d5b4; }
.swatch-2 { background: #ebbf94; }
.swatch-3 { background: #d6a47b; }
.swatch-4 { background: #b8845a; }
.swatch-5 { background: #8b5e3c; }
.swatch-6 { background: #5c3317; }

/* BSA selector */
.bsa-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(160px, 100%), 1fr));
  gap: var(--space-2);
}
.bsa-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--color-surface-2);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text);
  text-align: left;
  min-height: 44px;
  transition: all var(--transition-interactive);
}
.bsa-btn .bsa-pct {
  font-weight: 700;
  font-size: var(--text-sm);
  color: var(--color-sun);
}
.bsa-btn:hover {
  border-color: var(--color-sun);
  background: var(--color-sun-highlight);
}
.bsa-btn.selected {
  border-color: var(--color-sun);
  background: var(--color-sun-highlight);
  box-shadow: 0 0 0 1px var(--color-sun);
}

/* ====================================================================
   9. BUTTONS
   ==================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  min-height: 44px;
  transition: all var(--transition-interactive);
  white-space: nowrap;
}
.btn-primary {
  background: var(--color-primary);
  color: #fff;
}
.btn-primary:hover { background: var(--color-primary-hover); }
.btn-primary:active { background: var(--color-primary-active); }

.btn-sun {
  background: var(--color-sun);
  color: #fff;
}
.btn-sun:hover { background: var(--color-sun-hover); }

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 1.5px solid var(--color-primary);
}
.btn-outline:hover { background: var(--color-primary-highlight); }

.btn-ghost {
  background: transparent;
  color: var(--color-text-muted);
}
.btn-ghost:hover { background: var(--color-surface-offset); color: var(--color-text); }

.btn-danger {
  background: var(--color-error);
  color: #fff;
}
.btn-danger:hover { opacity: 0.85; }

.btn-lg { padding: var(--space-4) var(--space-8); font-size: var(--text-base); }
.btn-sm { padding: var(--space-2) var(--space-4); font-size: var(--text-xs); }
.btn-icon-only { padding: var(--space-2); width: 44px; height: 44px; border-radius: var(--radius-md); }

.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}

/* ====================================================================
   10. UV RISK BADGES / INDICATORS
   ==================================================================== */
.risk-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.risk-low       { background: oklch(from var(--color-risk-low) l c h / 0.15);       color: var(--color-risk-low); }
.risk-moderate  { background: oklch(from var(--color-risk-moderate) l c h / 0.15);  color: var(--color-risk-moderate); }
.risk-high      { background: oklch(from var(--color-risk-high) l c h / 0.15);      color: var(--color-risk-high); }
.risk-very-high { background: oklch(from var(--color-risk-very-high) l c h / 0.15); color: var(--color-risk-very-high); }
.risk-extreme   { background: oklch(from var(--color-risk-extreme) l c h / 0.15);   color: var(--color-risk-extreme); }

/* ====================================================================
   11. ALERT BANNERS
   ==================================================================== */
.alert {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  font-size: var(--text-sm);
  border: 1px solid transparent;
}
.alert-safe    { background: oklch(from var(--color-success) l c h / 0.10); border-color: oklch(from var(--color-success) l c h / 0.25); color: var(--color-success); }
.alert-info    { background: oklch(from var(--color-info) l c h / 0.10); border-color: oklch(from var(--color-info) l c h / 0.25); color: var(--color-info); }
.alert-caution { background: oklch(from var(--color-risk-moderate) l c h / 0.12); border-color: oklch(from var(--color-risk-moderate) l c h / 0.30); color: var(--color-risk-moderate); }
.alert-warning { background: oklch(from var(--color-warning) l c h / 0.12); border-color: oklch(from var(--color-warning) l c h / 0.30); color: var(--color-warning); }
.alert-danger  { background: oklch(from var(--color-error) l c h / 0.12); border-color: oklch(from var(--color-error) l c h / 0.35); color: var(--color-error); }
.alert-low-uvi { background: var(--color-primary-highlight); border-color: var(--color-primary); color: var(--color-primary); }

/* ====================================================================
   12. PROGRESS BAR
   ==================================================================== */
.progress-wrap {
  background: var(--color-surface-offset);
  border-radius: var(--radius-full);
  overflow: hidden;
  height: 12px;
  position: relative;
}
.progress-bar {
  height: 100%;
  border-radius: var(--radius-full);
  background: var(--color-success);
  transition: width 1s linear, background 0.5s;
}
.progress-bar.pct-50  { background: var(--color-info); }
.progress-bar.pct-75  { background: var(--color-risk-moderate); }
.progress-bar.pct-90  { background: var(--color-warning); }
.progress-bar.pct-100 { background: var(--color-error); }

/* ====================================================================
   13. LOCATION BLOCK
   ==================================================================== */
.location-block {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
}
.location-display {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.location-name {
  font-weight: 600;
  color: var(--color-text);
}

/* ====================================================================
   14. UV CHART CONTAINER
   ==================================================================== */
.chart-container {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  box-shadow: var(--shadow-sm);
}
.chart-caption {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
  text-align: center;
}

/* ====================================================================
   15. TIMER PAGE
   ==================================================================== */
.timer-display {
  font-family: var(--font-display);
  font-size: clamp(3rem, 10vw, 6rem);
  font-weight: 700;
  color: var(--color-text);
  text-align: center;
  letter-spacing: 0.04em;
  line-height: 1;
  padding: var(--space-8) 0;
}
.timer-display.burning { color: var(--color-error); }

.timer-status {
  text-align: center;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
  min-height: 1.5em;
}

.timer-controls {
  display: flex;
  justify-content: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  margin-top: var(--space-6);
}

.dose-meter {
  margin-top: var(--space-6);
}
.dose-meter-label {
  display: flex;
  justify-content: space-between;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}
.dose-meter-pct {
  font-weight: 700;
  font-size: var(--text-sm);
  color: var(--color-text);
}

/* Threshold markers */
.marker-row {
  display: flex;
  justify-content: space-between;
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: var(--space-1);
}

/* ====================================================================
   16. METHODOLOGY PAGE
   ==================================================================== */
.formula-block {
  background: var(--color-surface-offset);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  font-family: 'Courier New', 'Consolas', monospace;
  font-size: var(--text-sm);
  overflow-x: auto;
  color: var(--color-text);
  margin: var(--space-4) 0;
}
.formula-block strong { color: var(--color-primary); }

.method-table {
  width: 100%;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-border);
  margin: var(--space-4) 0;
}
.method-table th {
  background: var(--color-surface-offset);
  padding: var(--space-3) var(--space-4);
  text-align: left;
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
}
.method-table td {
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-text);
  border-top: 1px solid var(--color-divider);
}
.method-table tr:hover td { background: var(--color-surface-offset-2); }

.ref-list { list-style: decimal; padding-left: var(--space-6); }
.ref-list li {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding: var(--space-1) 0;
  line-height: 1.5;
}
.ref-list li a { color: var(--color-primary); }

/* ====================================================================
   17. FOOTER
   ==================================================================== */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-block: var(--space-8);
  margin-top: auto;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-6);
  align-items: start;
}
@media (max-width: 600px) {
  .footer-inner { grid-template-columns: 1fr; }
}

.footer-brand { font-family: var(--font-display); font-size: var(--text-lg); }
.footer-tagline { font-size: var(--text-sm); color: var(--color-text-muted); margin-top: var(--space-1); }
.footer-disclaimer {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: var(--space-4);
  max-width: 55ch;
  line-height: 1.5;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  text-align: right;
}
@media (max-width: 600px) { .footer-links { text-align: left; flex-direction: row; flex-wrap: wrap; } }

.footer-links a {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-decoration: none;
}
.footer-links a:hover { color: var(--color-primary); }

.footer-sources {
  grid-column: 1 / -1;
  border-top: 1px solid var(--color-divider);
  padding-top: var(--space-4);
  margin-top: var(--space-4);
}
.footer-sources-label {
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-faint);
  margin-bottom: var(--space-2);
}
.footer-sources ul {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  list-style: none;
}
.footer-sources a {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  text-decoration: none;
}
.footer-sources a:hover { color: var(--color-primary); }

/* ====================================================================
   18. UTILITY CLASSES
   ==================================================================== */
.text-muted   { color: var(--color-text-muted); }
.text-faint   { color: var(--color-text-faint); }
.text-sun     { color: var(--color-sun-text); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-error   { color: var(--color-error); }
.text-sm      { font-size: var(--text-sm); }
.text-xs      { font-size: var(--text-xs); }
.text-center  { text-align: center; }

.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.w-full { width: 100%; }

.hidden { display: none !important; }

.divider {
  border: none;
  border-top: 1px solid var(--color-divider);
  margin-block: var(--space-6);
}

/* Loading spinner */
.spinner {
  width: 20px; height: 20px;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  display: inline-block;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Skeleton */
@keyframes shimmer {
  0%   { background-position: -200% 0; }
  100% { background-position:  200% 0; }
}
.skeleton {
  background: linear-gradient(90deg,
    var(--color-surface-offset) 25%,
    var(--color-surface-dynamic) 50%,
    var(--color-surface-offset) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

/* Rule-of-nines advanced BSA panel */
.ron-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(200px, 100%), 1fr));
  gap: var(--space-2);
}
.ron-checkbox {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: var(--text-sm);
  transition: all var(--transition-interactive);
}
.ron-checkbox:has(input:checked) {
  background: var(--color-sun-highlight);
  border-color: var(--color-sun);
}
.ron-checkbox input { accent-color: var(--color-sun); width: 16px; height: 16px; }

/* Exposure history mini-table */
.history-table { font-size: var(--text-xs); }
.history-table th { font-size: var(--text-xs); }
.history-table td { font-size: var(--text-xs); vertical-align: middle; }

/* Notice box */
.notice {
  background: var(--color-sun-highlight);
  border: 1px solid var(--color-sun);
  color: var(--color-sun-text);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  font-size: var(--text-sm);
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
}
.notice-body { flex: 1; }
.notice-title { font-weight: 700; margin-bottom: var(--space-1); }

/* ====================================================================
   19. RESPONSIVE TWEAKS
   ==================================================================== */
@media (max-width: 480px) {
  .result-grid { grid-template-columns: 1fr 1fr; }
  .timer-controls { gap: var(--space-2); }
  .btn-lg { width: 100%; }
}