:root {
  --blue-600: #2563eb;
  --blue-400: #60a5fa;
  --orange-500: #f97316;
  --yellow-400: #facc15;
  --green-500: #22c55e;
  --red-500: #ef4444;
  --slate-950: #0f172a;
  --slate-800: #1e293b;
  --slate-600: #475569;
  --slate-100: #e2e8f0;
  --slate-50: #f8fafc;
  --white: #ffffff;
  --radius-lg: 24px;
  --radius-md: 18px;
  --shadow: 0 18px 50px rgba(37, 99, 235, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Trebuchet MS", "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(96, 165, 250, 0.18), transparent 28%),
    radial-gradient(circle at top right, rgba(249, 115, 22, 0.16), transparent 24%),
    var(--slate-50);
  color: var(--slate-950);
}

.site-header,
main {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 28px 0 18px;
}

.brand {
  display: flex;
  gap: 14px;
  align-items: center;
}

.brand-badge {
  width: 56px;
  height: 56px;
  border-radius: 18px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--orange-500), var(--yellow-400));
  color: var(--white);
  font-weight: 800;
  font-size: 1.5rem;
  box-shadow: var(--shadow);
}

.eyebrow,
.hero-kicker {
  margin: 0;
  color: var(--orange-500);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
}

.brand h1 {
  margin: 2px 0 0;
  font-size: 1.75rem;
}

.sound-toggle,
.btn {
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  font: inherit;
}

.sound-toggle {
  background: var(--white);
  color: var(--slate-800);
  padding: 12px 16px;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.08);
}

.hero {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 24px;
  align-items: stretch;
  padding: 18px 0 32px;
}

.hero-copy,
.hero-panel,
.principle {
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(226, 232, 240, 0.9);
  box-shadow: var(--shadow);
}

.hero-copy {
  padding: 32px;
  border-radius: var(--radius-lg);
}

.hero-copy h2 {
  margin: 10px 0 14px;
  font-size: clamp(2rem, 4vw, 3.4rem);
  line-height: 1.02;
}

.hero-text {
  max-width: 58ch;
  color: var(--slate-600);
  font-size: 1.05rem;
  line-height: 1.65;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 24px;
}

.btn {
  padding: 13px 20px;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
}

.btn-small {
  min-height: 38px;
  padding: 9px 14px;
  font-size: 0.92rem;
}

.btn-primary {
  background: linear-gradient(135deg, var(--orange-500), var(--yellow-400));
  color: var(--white);
}

.btn-secondary {
  background: var(--white);
  color: var(--slate-800);
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.08);
}

.hero-panel {
  padding: 20px;
  border-radius: var(--radius-lg);
  display: grid;
  gap: 14px;
}

.panel-card {
  border-radius: var(--radius-md);
  padding: 18px;
  color: var(--white);
}

.panel-card h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
}

.panel-card p {
  margin: 0;
  line-height: 1.5;
}

.panel-card-blue {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-400));
}

.panel-card-orange {
  background: linear-gradient(135deg, #fb7185, var(--orange-500));
}

.panel-card-green {
  background: linear-gradient(135deg, var(--green-500), #34d399);
}

.principles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  padding-bottom: 40px;
}

.principle {
  border-radius: var(--radius-md);
  padding: 22px;
}

.principle-index {
  display: inline-block;
  margin-bottom: 10px;
  font-size: 0.88rem;
  font-weight: 800;
  color: var(--blue-600);
}

.principle h3 {
  margin: 0 0 10px;
}

.principle p {
  margin: 0;
  color: var(--slate-600);
  line-height: 1.6;
}

.flash-stack {
  display: grid;
  gap: 10px;
  margin-bottom: 18px;
}

.flash {
  border-radius: 16px;
  padding: 14px 16px;
  font-weight: 700;
}

.flash-success {
  background: rgba(34, 197, 94, 0.14);
  color: #166534;
}

.flash-warning {
  background: rgba(250, 204, 21, 0.18);
  color: #854d0e;
}

.flash-danger {
  background: rgba(239, 68, 68, 0.14);
  color: #991b1b;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 20px;
}

.pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 8px 14px;
  background: var(--white);
  border-radius: 999px;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.06);
  color: var(--slate-800);
  font-size: 0.92rem;
}

.pill-link {
  text-decoration: none;
}

.auth-shell {
  display: grid;
  grid-template-columns: 0.95fr 0.8fr;
  gap: 24px;
  padding: 16px 0 36px;
}

.auth-card,
.demo-card,
.surface {
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(226, 232, 240, 0.9);
  box-shadow: var(--shadow);
  border-radius: var(--radius-lg);
}

.auth-card,
.demo-card,
.surface {
  padding: 26px;
}

.auth-card h2 {
  margin: 10px 0 12px;
}

.auth-text,
.muted {
  color: var(--slate-600);
  line-height: 1.6;
}

.auth-form {
  display: grid;
  gap: 14px;
  margin-top: 20px;
}

.auth-form label {
  display: grid;
  gap: 8px;
  font-weight: 700;
}

.auth-form input,
.auth-form select {
  width: 100%;
  min-height: 48px;
  padding: 12px 14px;
  border: 1px solid var(--slate-100);
  border-radius: 16px;
  font: inherit;
  background: var(--white);
}

.demo-list,
.list-stack,
.table-like {
  display: grid;
  gap: 12px;
}

.list-actions {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.demo-item,
.list-row,
.table-row {
  display: grid;
  gap: 4px;
  padding: 14px;
  border-radius: 16px;
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.95), rgba(241, 245, 249, 0.95));
}

.demo-item code {
  display: inline-block;
  width: fit-content;
  padding: 4px 8px;
  border-radius: 10px;
  background: rgba(37, 99, 235, 0.1);
  color: var(--blue-600);
}

.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  padding-bottom: 36px;
}

.surface-featured {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.96), rgba(96, 165, 250, 0.9));
  color: var(--white);
}

.surface-featured .muted,
.surface-featured .hero-kicker {
  color: rgba(255, 255, 255, 0.88);
}

.surface-full {
  grid-column: 1 / -1;
}

.surface h3,
.surface-featured h2 {
  margin-top: 0;
}

.stat-row,
.stats-grid {
  display: grid;
  gap: 12px;
}

.stat-row {
  grid-template-columns: repeat(2, 1fr);
  margin-top: 20px;
}

.stats-grid {
  grid-template-columns: repeat(2, 1fr);
}

.mini-stat {
  padding: 14px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.18);
}

.surface .mini-stat {
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.95), rgba(241, 245, 249, 0.95));
}

.mini-stat span {
  display: block;
  color: var(--slate-600);
  font-size: 0.86rem;
  margin-bottom: 6px;
}

.surface-featured .mini-stat span {
  color: rgba(255, 255, 255, 0.84);
}

.mini-stat strong {
  font-size: 1.6rem;
}

.list-row,
.table-row {
  grid-template-columns: 1fr auto;
  align-items: center;
}

.table-row {
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.inline-form,
.stack-form {
  display: grid;
  gap: 12px;
  margin-bottom: 18px;
}

.inline-form {
  grid-template-columns: 1fr 1.5fr auto;
  align-items: end;
}

.stack-form.two-columns {
  grid-template-columns: repeat(2, 1fr);
}

.stack-form label,
.inline-form label {
  display: grid;
  gap: 8px;
  font-weight: 700;
}

.stack-form input,
.stack-form select,
.inline-form input,
.inline-form select {
  width: 100%;
  min-height: 46px;
  padding: 11px 13px;
  border: 1px solid var(--slate-100);
  border-radius: 14px;
  font: inherit;
  background: var(--white);
}

.grow {
  grid-column: 1 / -1;
}

.quiz-shell {
  display: grid;
  gap: 20px;
  padding-bottom: 36px;
}

.quiz-meta {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-top: 18px;
}

.progress-track {
  width: 100%;
  height: 14px;
  border-radius: 999px;
  background: rgba(226, 232, 240, 0.9);
  overflow: hidden;
  margin-bottom: 20px;
}

.progress-bar {
  width: 0%;
  height: 100%;
  background: linear-gradient(135deg, var(--orange-500), var(--yellow-400));
  transition: width 0.2s ease;
}

.quiz-options {
  display: grid;
  gap: 12px;
  margin-top: 18px;
}

.quiz-option {
  width: 100%;
  min-height: 56px;
  border: 0;
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.98), rgba(241, 245, 249, 0.98));
  padding: 14px 16px;
  text-align: left;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.06);
}

.quiz-option:hover {
  transform: translateY(-1px);
}

.quiz-feedback {
  margin-top: 18px;
  padding: 16px;
  border-radius: 18px;
  font-weight: 700;
}

.quiz-feedback.is-correct {
  background: rgba(34, 197, 94, 0.14);
  color: #166534;
}

.quiz-feedback.is-wrong {
  background: rgba(239, 68, 68, 0.14);
  color: #991b1b;
}

.quiz-review {
  padding: 14px;
  border-radius: 16px;
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.98), rgba(241, 245, 249, 0.98));
}

.quiz-review p {
  margin: 8px 0 0;
  color: var(--slate-600);
  line-height: 1.55;
}

.list-row p {
  margin: 2px 0 0;
  color: var(--slate-600);
}

@media (max-width: 900px) {
  .hero,
  .principles,
  .auth-shell,
  .dashboard-grid {
    grid-template-columns: 1fr;
  }

  .site-header {
    gap: 12px;
    flex-direction: column;
    align-items: flex-start;
  }

  .surface-full {
    grid-column: auto;
  }

  .table-row,
  .list-row,
  .stats-grid,
  .stat-row,
  .inline-form,
  .stack-form.two-columns,
  .quiz-meta {
    grid-template-columns: 1fr;
  }
}