:root {
  --bg: #ecfeff;
  --card: #ffffff;
  --text: #12303b;
  --muted: #4e6a73;
  --line: #b6e5ec;
  --primary: #0891b2;
  --primary-strong: #0e7490;
  --success: #0f8a4f;
  --alert-bg: #cffafe;
  --shadow: 0 12px 24px rgba(8, 145, 178, 0.12);
  --radius: 20px;
}

* {
  box-sizing: border-box;
}

html,
body {
  overflow-x: hidden;
}

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: linear-gradient(180deg, #ecfeff 0%, #f8fdff 48%, #ffffff 100%);
  color: var(--text);
  line-height: 1.45;
}

a {
  color: inherit;
  text-decoration: none;
}

.wrap {
  width: min(100%, 980px);
  margin: 0 auto;
  padding: 0 1rem;
}

.topbar {
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(10px);
}

.topbar__inner {
  min-height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;
}

.topbar__nav {
  display: flex;
  gap: 0.75rem;
  font-size: 0.95rem;
  flex-wrap: wrap;
}

.topbar__nav a,
.brand {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.brand {
  font-weight: 800;
  color: var(--primary-strong);
}

.page {
  padding-top: 1rem;
  padding-bottom: 3rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1rem;
  margin-bottom: 1rem;
}

.stack > * + * {
  margin-top: 0.9rem;
}

.hero h1,
.practice-header h1,
.progress-page h1 {
  margin: 0;
  font-size: 1.65rem;
}

.field {
  display: grid;
  gap: 0.5rem;
}

.field input[type="text"] {
  width: 100%;
  min-height: 48px;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.9rem 1rem;
  font-size: 1rem;
  background: #fff;
}

.field input[type="text"]:focus {
  outline: 2px solid rgba(8, 145, 178, 0.25);
  border-color: var(--primary);
}

.topic-grid,
.answer-list,
.action-grid,
.lesson-list,
.notation-grid {
  display: grid;
  gap: 0.8rem;
}

.topic-card,
.answer-option {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 0.8rem;
  align-items: start;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 0.9rem;
  background: #fff;
  min-width: 0;
}

.topic-card__content {
  display: grid;
  gap: 0.35rem;
  min-width: 0;
}

.topic-card__title {
  font-weight: 700;
  overflow-wrap: anywhere;
}

.topic-card__body,
.lesson-list__item p,
.eyebrow,
.progress-chip,
.pill,
.alert,
.focus-check p:last-child,
.muted,
small {
  color: var(--muted);
}

.lesson-list__item,
.topic-summary {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 1rem;
  padding: 0.8rem 0;
  border-top: 1px solid var(--line);
}

.lesson-list__item:first-of-type,
.topic-summary:first-of-type {
  border-top: 0;
}

.btn {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
  color: var(--text);
  min-height: 48px;
  padding: 0.85rem 1rem;
  font-size: 1rem;
  font-weight: 600;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  width: 100%;
}

button.btn {
  cursor: pointer;
}

.btn--primary {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.btn--primary:hover,
.btn--primary:focus {
  background: var(--primary-strong);
}

.btn--full {
  width: 100%;
}

button:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.alert {
  background: var(--alert-bg);
  border: 1px solid #9ee7f5;
  border-radius: 16px;
  padding: 0.9rem 1rem;
  margin-bottom: 1rem;
}

.practice-header {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 1rem;
}

.progress-chip,
.pill {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  background: #ecfeff;
  padding: 0.35rem 0.7rem;
  font-size: 0.9rem;
}

.question-body p,
.question-body ul,
.question-body li {
  font-size: 1.02rem;
}

.action-grid {
  grid-template-columns: 1fr;
}

.action-grid > *,
.action-grid form {
  width: 100%;
  min-width: 0;
}

.notation-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.notation-card {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 1rem;
  display: grid;
  gap: 0.25rem;
}

.focus-check {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 0.9rem;
}

.home-subsection {
  padding-top: 0.25rem;
}

.home-subsection + .home-subsection {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

@media (min-width: 700px) {
  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .action-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 520px) {
  .topbar__inner,
  .practice-header,
  .lesson-list__item,
  .topic-summary {
    flex-direction: column;
  }

  .wrap {
    padding: 0 0.85rem;
  }

  .card {
    padding: 0.9rem;
  }

  .topic-card,
  .answer-option {
    gap: 0.65rem;
  }

  .notation-grid {
    grid-template-columns: 1fr;
  }

  .topic-summary__meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
  }
}


.site-footer {
  margin-top: 2rem;
  border-top: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.9);
}

.site-footer__inner {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1rem;
  padding-bottom: 1.5rem;
  flex-wrap: wrap;
  align-items: center;
}

.site-footer__copy {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.site-footer__nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.site-footer__nav a {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  color: var(--primary-strong);
  font-weight: 600;
}

.legal-page {
  max-width: 760px;
}

.legal-page__updated {
  margin: 0;
}

.legal-page__sections {
  margin-top: 1rem;
}

.legal-page__section h2 {
  margin-bottom: 0.35rem;
}

.legal-page__section p {
  margin-top: 0;
  color: var(--muted);
}