:root {
  --font-body: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --surface: #f6f7fb;
  --surface-elevated: #ffffff;
  --surface-overlay: rgba(255, 255, 255, 0.75);
  --surface-muted: #eef1f8;
  --surface-dark: #12131a;
  --surface-dark-elevated: #1d1f2a;
  --surface-dark-overlay: rgba(18, 19, 26, 0.7);
  --surface-dark-muted: #1a1b24;
  --text: #161822;
  --text-soft: #454a5f;
  --text-subtle: #6c7188;
  --text-inverse: #f5f6fb;
  --accent: #3a7afe;
  --accent-soft: rgba(58, 122, 254, 0.15);
  --accent-strong: #2255d3;
  --warning: #f97316;
  --radius-lg: 32px;
  --radius-md: 20px;
  --radius-sm: 14px;
  --shadow-soft: 0 25px 55px -35px rgba(20, 30, 75, 0.35);
  --shadow-strong: 0 40px 70px -30px rgba(11, 20, 60, 0.45);
  --transition: 280ms cubic-bezier(0.22, 1, 0.36, 1);
}

:root.dark {
  --surface: #0d0f17;
  --surface-elevated: #151823;
  --surface-overlay: rgba(21, 24, 35, 0.75);
  --surface-muted: #1a1d2a;
  --text: #f1f2f8;
  --text-soft: #c4c8de;
  --text-subtle: #9ea4bc;
  --accent: #8ab6ff;
  --accent-soft: rgba(138, 182, 255, 0.22);
  --accent-strong: #cfe0ff;
  --warning: #fbbf24;
  --shadow-soft: 0 25px 55px -35px rgba(7, 12, 28, 0.8);
  --shadow-strong: 0 45px 90px -40px rgba(0, 0, 0, 0.7);
  color-scheme: dark;
}

html {
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  font-family: var(--font-body);
  color: var(--text);
  background: radial-gradient(circle at 20% -10%, rgba(58, 122, 254, 0.13), transparent 55%),
    radial-gradient(circle at 80% 0%, rgba(134, 172, 255, 0.18), transparent 55%), var(--surface);
  min-height: 100%;
  scroll-behavior: smooth;
}

body {
  display: flex;
  justify-content: center;
  padding: clamp(24px, 5vw, 56px);
}

.page {
  width: min(960px, 100%);
  display: flex;
  flex-direction: column;
  gap: clamp(32px, 5vw, 56px);
}

.hero {
  background: linear-gradient(135deg, rgba(58, 122, 254, 0.18), transparent 60%), var(--surface-elevated);
  border-radius: var(--radius-lg);
  padding: clamp(32px, 6vw, 56px);
  box-shadow: var(--shadow-soft);
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 20% -10%, rgba(58, 122, 254, 0.2), transparent 55%),
    radial-gradient(circle at 90% 20%, rgba(77, 182, 255, 0.25), transparent 50%);
  mix-blend-mode: screen;
  opacity: 0.7;
  pointer-events: none;
}

.hero__top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 600;
  color: inherit;
  text-decoration: none;
}

.brand img {
  filter: drop-shadow(0 12px 24px rgba(14, 24, 58, 0.3));
  border-radius: 18px;
}

.hero__actions {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.hero__link {
  display: inline-flex;
  align-items: center;
  font-weight: 600;
  text-decoration: none;
  color: inherit;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(15, 23, 42, 0.08);
  transition: transform var(--transition), background var(--transition);
}

.hero__link:hover,
.hero__link:focus-visible {
  transform: translateY(-1px);
  background: rgba(58, 122, 254, 0.18);
  outline: none;
}

:root.dark .hero__link {
  background: rgba(255, 255, 255, 0.12);
}

:root.dark .hero__link:hover,
:root.dark .hero__link:focus-visible {
  background: rgba(140, 185, 255, 0.25);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  border: none;
  border-radius: 999px;
  padding: 10px 18px;
  font-size: 0.95rem;
  background: rgba(255, 255, 255, 0.7);
  color: var(--text);
  cursor: pointer;
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition), background var(--transition);
}

.theme-toggle:hover {
  transform: translateY(-2px);
  background: rgba(255, 255, 255, 0.85);
}

:root.dark .theme-toggle {
  background: rgba(21, 24, 35, 0.75);
  color: var(--text);
}

.theme-toggle__icon {
  font-size: 1.25rem;
}

.hero__copy {
  margin-top: clamp(20px, 4vw, 32px);
  position: relative;
  z-index: 1;
}

.eyebrow {
  font-size: 0.85rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-strong);
  margin-bottom: 12px;
}

h1 {
  font-size: clamp(2.4rem, 4vw, 3.2rem);
  margin: 0 0 16px;
  line-height: 1.1;
}

.hero__copy p {
  max-width: 60ch;
  font-size: 1.05rem;
  color: var(--text-soft);
}

.quick-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

.chip {
  padding: 10px 18px;
  border-radius: 999px;
  border: 1px solid rgba(58, 122, 254, 0.35);
  color: var(--accent-strong);
  background: rgba(58, 122, 254, 0.08);
  text-decoration: none;
  font-weight: 500;
  transition: transform var(--transition), background var(--transition), border-color var(--transition);
}

.chip:hover {
  transform: translateY(-2px);
  background: rgba(58, 122, 254, 0.2);
}

.panel {
  background: var(--surface-elevated);
  border-radius: var(--radius-lg);
  padding: clamp(32px, 5vw, 48px);
  box-shadow: var(--shadow-soft);
  position: relative;
  overflow: hidden;
}

.panel[data-animate] {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 480ms var(--transition), transform 480ms var(--transition);
}

.panel.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.panel__header h2 {
  margin: 0 0 12px;
  font-size: clamp(1.8rem, 3vw, 2.4rem);
}

.panel__header p {
  margin: 0;
  color: var(--text-subtle);
  max-width: 60ch;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: clamp(20px, 4vw, 28px);
  margin-top: clamp(24px, 4vw, 32px);
}

.card {
  background: var(--surface);
  border-radius: var(--radius-md);
  padding: 24px;
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.08);
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
}

.card::before {
  content: '';
  position: absolute;
  inset: auto 0 0 0;
  height: 6px;
  background: linear-gradient(90deg, rgba(58, 122, 254, 0.7), rgba(138, 182, 255, 0.9));
  opacity: 0;
  transition: opacity var(--transition);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-strong);
  background: var(--surface-elevated);
}

.card:hover::before,
.card[data-open]::before {
  opacity: 1;
}

.card h3 {
  margin: 0 0 12px;
}

.figure {
  margin: 0 0 8px;
}

.figure__value {
  font-size: 2.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.card__summary {
  margin: 0 0 16px;
  color: var(--text-subtle);
}

.card__detail {
  border: none;
  background: rgba(58, 122, 254, 0.12);
  color: var(--accent-strong);
  border-radius: 999px;
  padding: 8px 16px;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition);
}

.card__detail:hover,
.card__detail:focus-visible {
  background: rgba(58, 122, 254, 0.2);
  transform: translateY(-1px);
}

.card__extra {
  margin-top: 18px;
  padding: 18px;
  border-radius: var(--radius-sm);
  background: rgba(58, 122, 254, 0.1);
  color: var(--text-soft);
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.2);
}

.card__extra p {
  margin-top: 0;
  margin-bottom: 12px;
}

.card__extra .source-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.panel--overlay::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(145deg, rgba(58, 122, 254, 0.12), transparent 55%),
    linear-gradient(325deg, rgba(255, 255, 255, 0.55), transparent 65%);
  pointer-events: none;
}

.toggle {
  display: inline-flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 24px;
}

.toggle__btn {
  border: none;
  border-radius: 999px;
  padding: 10px 18px;
  background: rgba(58, 122, 254, 0.12);
  color: var(--accent-strong);
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.2);
}

.toggle__btn[aria-selected='true'] {
  background: rgba(58, 122, 254, 0.3);
  transform: translateY(-2px);
  box-shadow: var(--shadow-soft);
}

.toggle-panels {
  margin-top: 28px;
  position: relative;
  min-height: 200px;
}

.toggle-panel {
  background: rgba(255, 255, 255, 0.6);
  border-radius: var(--radius-md);
  padding: clamp(20px, 4vw, 32px);
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.12);
  transition: opacity var(--transition), transform var(--transition);
  opacity: 0;
  transform: translateY(24px);
  position: absolute;
  inset: 0;
}

.toggle-panel.is-active {
  opacity: 1;
  transform: translateY(0);
  position: relative;
}

.toggle-panel[hidden] {
  display: none;
}

.callout {
  margin: 16px 0;
  padding: 16px;
  border-radius: var(--radius-sm);
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-weight: 600;
}

.habits {
  display: grid;
  gap: clamp(24px, 4vw, 32px);
  align-items: start;
}

.habit-meter {
  background: var(--surface);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.12);
}

.habit-meter label {
  display: block;
  font-weight: 600;
  margin-bottom: 12px;
}

input[type='range'] {
  width: 100%;
  accent-color: var(--accent);
}

.habit-meter__status {
  margin-top: 16px;
  font-weight: 600;
  color: var(--accent-strong);
}

.habit-checklist {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.habit-checklist input[type='checkbox'] {
  accent-color: var(--accent);
}

.habit-checklist label {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--surface);
  border-radius: var(--radius-sm);
  padding: 16px;
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.08);
}

.habit-tips {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: clamp(24px, 4vw, 32px);
}

.tip {
  background: rgba(58, 122, 254, 0.1);
  border-radius: var(--radius-md);
  padding: 24px;
  color: var(--text-soft);
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.22);
  transition: transform var(--transition), box-shadow var(--transition);
}

.tip:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-soft);
}

.tip h3 {
  margin-top: 0;
  color: var(--text);
}

.tip__note {
  margin-bottom: 0;
  font-weight: 600;
  color: var(--accent-strong);
}

.panel--muted {
  background: var(--surface-muted);
}

.source-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  margin-top: clamp(24px, 4vw, 32px);
}

.source-card {
  background: var(--surface-elevated);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: inset 0 0 0 1px rgba(58, 122, 254, 0.08);
  transition: transform var(--transition), box-shadow var(--transition);
}

.source-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-soft);
}

.source-link {
  color: var(--accent-strong);
  font-weight: 600;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.source-link::after {
  content: '↗';
  font-size: 0.85em;
}

.page__footer {
  text-align: center;
  color: var(--text-subtle);
  background: var(--surface-elevated);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-soft);
}

[data-animate].is-visible,
.card[data-open],
.tip:hover,
.source-card:hover {
  transition-delay: 40ms;
}

.card[data-open] {
  background: var(--surface-elevated);
  box-shadow: var(--shadow-strong);
}

.card[data-open] .card__detail {
  background: rgba(58, 122, 254, 0.25);
}

:root.dark body {
  background: radial-gradient(circle at 20% -10%, rgba(30, 64, 175, 0.35), transparent 55%),
    radial-gradient(circle at 80% 0%, rgba(14, 116, 144, 0.25), transparent 55%), var(--surface);
}

:root.dark .hero {
  background: linear-gradient(135deg, rgba(45, 80, 160, 0.45), transparent 60%), var(--surface-dark);
}

:root.dark .theme-toggle {
  box-shadow: var(--shadow-soft);
}

:root.dark .chip {
  border-color: rgba(138, 182, 255, 0.4);
  background: rgba(138, 182, 255, 0.12);
  color: var(--text);
}

:root.dark .card,
:root.dark .habit-meter,
:root.dark .habit-checklist label,
:root.dark .toggle-panel,
:root.dark .source-card,
:root.dark .panel {
  background: var(--surface-dark-elevated);
  color: var(--text);
  box-shadow: inset 0 0 0 1px rgba(138, 182, 255, 0.16);
}

:root.dark .panel--muted {
  background: var(--surface-dark-muted);
}

:root.dark .card__extra,
:root.dark .callout,
:root.dark .tip,
:root.dark .habit-meter,
:root.dark .habit-checklist label {
  background: rgba(138, 182, 255, 0.12);
  box-shadow: inset 0 0 0 1px rgba(138, 182, 255, 0.25);
}

:root.dark .card__detail,
:root.dark .toggle__btn,
:root.dark .source-link {
  color: var(--accent-strong);
}

:root.dark .page__footer {
  background: var(--surface-dark-elevated);
}

@media (max-width: 720px) {
  body {
    padding: 20px;
  }

  .hero,
  .panel,
  .page__footer {
    border-radius: 24px;
  }

  .theme-toggle {
    padding: 8px 14px;
  }
}

@media (max-width: 560px) {
  .hero__top {
    flex-direction: column;
    align-items: flex-start;
  }

  .toggle__btn {
    flex: 1 1 100%;
  }

  .habit-checklist label {
    flex-direction: column;
    align-items: flex-start;
  }
}
.theme-toggle--pulse {
  animation: pulse 0.4s ease;
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translate(-50%, 20px);
  background: rgba(58, 122, 254, 0.95);
  color: #fff;
  padding: 12px 20px;
  border-radius: 999px;
  box-shadow: var(--shadow-strong);
  opacity: 0;
  pointer-events: none;
  transition: opacity 220ms ease, transform 220ms ease;
  z-index: 999;
}

.toast--visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

@keyframes pulse {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.04);
  }
  100% {
    transform: scale(1);
  }
}