:root {
  color-scheme: light;
  --ink: #1f2937;
  --muted: #64748b;
  --soft: #f8fafc;
  --paper: #f3f6fb;
  --panel: #ffffff;
  --line: #dbe3ee;
  --blue: #2f6fb3;
  --teal: #147a73;
  --gold: #b7791f;
  --rose: #b5475b;
  --blue-soft: #eaf2fb;
  --teal-soft: #e7f5f2;
  --gold-soft: #fff5df;
  --rose-soft: #faedf0;
  --shadow: 0 18px 48px rgba(31, 41, 55, 0.1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

a {
  color: inherit;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px clamp(18px, 5vw, 64px);
  border-bottom: 1px solid var(--line);
  background: rgba(248, 250, 252, 0.92);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 850;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 40px;
  height: 40px;
  place-items: center;
  border-radius: 8px;
  color: #fff;
  background: var(--blue);
}

.topnav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 6px;
}

.topnav a,
.button,
.page-link,
.topic-pill,
.quiz-options button,
.resource-link {
  border-radius: 8px;
  font: inherit;
}

.topnav a {
  padding: 9px 11px;
  color: var(--muted);
  text-decoration: none;
}

.topnav a:hover,
.topnav a.active {
  color: var(--ink);
  background: #e8edf4;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(360px, 0.8fr);
  gap: clamp(28px, 5vw, 68px);
  align-items: center;
  min-height: calc(100vh - 70px);
  padding: clamp(38px, 7vw, 84px) clamp(18px, 5vw, 64px) 36px;
}

.hero-copy {
  max-width: 760px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--teal);
  font-size: 0.78rem;
  font-weight: 850;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p,
li,
a,
button {
  overflow-wrap: anywhere;
  letter-spacing: 0;
}

h1 {
  margin: 0;
  font-size: clamp(2.4rem, 6vw, 5.4rem);
  line-height: 0.98;
}

h2 {
  margin: 0;
  font-size: clamp(1.7rem, 3.1vw, 3rem);
  line-height: 1.06;
}

h3 {
  margin: 0;
  font-size: 1.22rem;
  line-height: 1.22;
}

.hero-copy > p:not(.eyebrow),
.page-lead,
.section-heading p,
.card p,
.topic-card p,
.resource-link span,
.side-note p,
.quiz-feedback,
footer {
  color: var(--muted);
  line-height: 1.62;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 11px 16px;
  border: 1px solid transparent;
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
}

.button.primary {
  color: #fff;
  background: var(--blue);
}

.button.secondary {
  color: var(--ink);
  background: #fff;
  border-color: var(--line);
}

.study-board {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: var(--shadow);
}

.board-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.dot.blue {
  background: var(--blue);
}

.dot.green {
  background: var(--teal);
}

.dot.gold {
  background: var(--gold);
}

.board-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 14px;
}

.board-card {
  min-height: 132px;
  padding: 15px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.board-card.large {
  grid-row: span 2;
  background: var(--blue-soft);
}

.board-card span,
.standard-strip span,
.topic-card span {
  display: block;
  color: var(--teal);
  font-size: 0.78rem;
  font-weight: 850;
  text-transform: uppercase;
}

.board-card strong {
  display: block;
  margin: 10px 0;
  font-size: clamp(1.4rem, 4vw, 2.4rem);
}

.board-card small,
.standard-strip small {
  color: var(--muted);
  line-height: 1.4;
}

.mini-map {
  display: grid;
  gap: 10px;
  margin-top: 16px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.mini-map span {
  display: block;
  height: 10px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--blue), var(--teal));
}

.dashboard-link {
  display: grid;
  gap: 5px;
  margin-top: 14px;
  padding: 15px;
  border: 1px solid var(--blue);
  border-radius: 8px;
  background: var(--blue);
  color: #fff;
  text-decoration: none;
}

.dashboard-link strong {
  font-size: 1.05rem;
}

.dashboard-link span {
  color: rgba(255, 255, 255, 0.82);
  line-height: 1.45;
}

.standard-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  padding: 0 clamp(18px, 5vw, 64px) 62px;
}

.teacher-portal {
  display: block;
  margin: 0 clamp(18px, 5vw, 64px) 62px;
  padding: clamp(22px, 4vw, 36px);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: var(--shadow);
}

.teacher-copy {
  display: grid;
  align-content: center;
  max-width: 920px;
}

.teacher-copy h2 {
  margin-bottom: 12px;
}

.teacher-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0 4px;
}

.teacher-stats span {
  display: inline-flex;
  min-height: 32px;
  align-items: center;
  padding: 7px 10px;
  border-radius: 999px;
  background: var(--blue-soft);
  color: var(--blue);
  font-size: 0.82rem;
  font-weight: 850;
}

.teacher-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.teacher-details {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 16px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
}

.teacher-details strong {
  display: block;
  margin-bottom: 8px;
}

.teacher-details ul {
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
  line-height: 1.55;
}

.teacher-details p {
  margin: 6px 0;
}

.teacher-details a {
  color: var(--blue);
  font-weight: 800;
}

.standard-strip article {
  min-height: 132px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 10px 26px rgba(31, 41, 55, 0.07);
}

.standard-strip strong {
  display: block;
  margin: 10px 0;
  font-size: 1.14rem;
}

.workspace {
  display: grid;
  grid-template-columns: 284px minmax(0, 1fr);
  gap: 22px;
  padding: 62px clamp(18px, 5vw, 64px);
  background: #edf2f7;
}

.side-panel,
.page-hero,
.card,
.quiz-shell {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 12px 30px rgba(31, 41, 55, 0.08);
}

.side-panel {
  position: sticky;
  top: 92px;
  align-self: start;
  padding: 18px;
}

.page-nav {
  display: grid;
  gap: 8px;
}

.page-link {
  display: block;
  padding: 12px;
  border: 1px solid var(--line);
  color: var(--muted);
  background: #fbfdff;
  text-align: left;
  text-decoration: none;
}

.page-link.active {
  color: #fff;
  border-color: var(--blue);
  background: var(--blue);
}

.side-note {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.page-content {
  min-width: 0;
}

.page-hero {
  padding: clamp(24px, 4vw, 38px);
}

.page-actions,
.topic-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.tag {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 6px 9px;
  border-radius: 999px;
  color: #fff;
  background: var(--teal);
  font-size: 0.78rem;
  font-weight: 850;
}

.tag.external {
  background: var(--blue);
}

.tag.internal {
  background: var(--teal);
}

.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 380px);
  gap: 18px;
  margin-top: 18px;
}

.card {
  padding: 22px;
  margin-bottom: 18px;
}

.card.blue {
  background: var(--blue-soft);
}

.card.green {
  background: var(--teal-soft);
}

.card.gold {
  background: var(--gold-soft);
}

.card.rose {
  background: var(--rose-soft);
}

.topic-grid,
.formula-grid,
.resource-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.topic-card,
.formula-tile,
.resource-link {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.topic-card strong,
.formula-tile strong,
.resource-link strong {
  display: block;
  color: var(--ink);
}

.topic-card ul,
.check-list {
  display: grid;
  gap: 8px;
  margin: 12px 0 0;
  padding-left: 18px;
  color: var(--muted);
  line-height: 1.5;
}

.formula-tile strong {
  color: var(--gold);
  font-family: "Segoe UI", ui-monospace, monospace;
}

.formula-tile span {
  display: block;
  margin-top: 7px;
  color: var(--muted);
  line-height: 1.45;
}

.resource-link {
  display: grid;
  gap: 5px;
  text-decoration: none;
}

.practice-zone {
  min-height: 100vh;
  padding: 82px clamp(18px, 5vw, 64px);
  background: #fff;
}

.section-heading {
  max-width: 760px;
  margin-bottom: 22px;
}

.practice-controls {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 16px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
}

.practice-controls label {
  display: grid;
  gap: 6px;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
}

.practice-controls select {
  width: 100%;
  min-height: 44px;
  padding: 9px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  font: inherit;
}

.rewards-dashboard {
  display: grid;
  grid-template-columns: 1.45fr 0.8fr 0.8fr 1.2fr;
  gap: 12px;
  margin-bottom: 16px;
}

.reward-card {
  min-height: 132px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 10px 26px rgba(31, 41, 55, 0.07);
}

.reward-level {
  background: var(--blue-soft);
}

.reward-label {
  display: block;
  color: var(--teal);
  font-size: 0.78rem;
  font-weight: 850;
  text-transform: uppercase;
}

.reward-card strong {
  display: block;
  margin: 12px 0 6px;
  font-size: 1.4rem;
}

.reward-card small,
.reward-card p {
  color: var(--muted);
}

.xp-bar {
  height: 12px;
  margin: 14px 0 10px;
  border-radius: 999px;
  background: #dce6f2;
  overflow: hidden;
}

.xp-bar span {
  display: block;
  width: 0%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--blue), var(--teal));
  transition: width 220ms ease;
}

.badge-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 6px 9px;
  border-radius: 999px;
  background: #edf2f7;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 850;
}

.badge.unlocked {
  background: var(--gold-soft);
  color: var(--gold);
}

.quiz-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 20px;
  padding: 20px;
}

.quiz-main {
  padding: 8px;
}

.quiz-standard {
  margin: 0 0 12px;
  color: var(--teal);
  font-weight: 850;
}

.quiz-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.quiz-meta span {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 5px 8px;
  border-radius: 999px;
  background: var(--blue-soft);
  color: var(--blue);
  font-size: 0.78rem;
  font-weight: 850;
}

.quiz-options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 18px;
}

.quiz-options button {
  min-height: 58px;
  padding: 12px;
  border: 1px solid var(--line);
  background: #f8fafc;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
}

.quiz-options button.correct {
  border-color: var(--teal);
  background: #e4f4ef;
}

.quiz-options button.wrong {
  border-color: var(--rose);
  background: #faedf0;
}

.quiz-feedback {
  min-height: 52px;
  margin: 18px 0 0;
}

.worked-solution {
  display: none;
  margin-top: 14px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfdff;
  color: var(--muted);
  line-height: 1.55;
}

.worked-solution.visible {
  display: block;
}

.worked-solution strong {
  display: block;
  margin-bottom: 8px;
  color: var(--ink);
}

.worked-solution ol,
.worked-solution ul {
  margin: 8px 0 0;
  padding-left: 20px;
}

.progress-panel {
  display: grid;
  justify-items: center;
  align-content: center;
  gap: 16px;
  padding: 18px;
  border-left: 1px solid var(--line);
}

.progress-ring {
  display: grid;
  width: 132px;
  height: 132px;
  place-items: center;
  border-radius: 50%;
  background: conic-gradient(var(--teal) 0deg, #e5eaf1 0deg);
  color: var(--ink);
  font-size: 1.65rem;
  font-weight: 900;
}

footer {
  padding: 28px clamp(18px, 5vw, 64px) 42px;
  border-top: 1px solid var(--line);
  background: #fff;
}

@media (max-width: 1060px) {
  .hero,
  .teacher-portal,
  .workspace,
  .content-grid,
  .quiz-shell {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
  }

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

  .side-panel {
    position: static;
  }

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

  .progress-panel {
    border-left: 0;
    border-top: 1px solid var(--line);
  }
}

@media (max-width: 680px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .topnav {
    justify-content: flex-start;
  }

  .standard-strip,
  .teacher-details,
  .board-grid,
  .topic-grid,
  .formula-grid,
  .resource-grid,
  .practice-controls,
  .quiz-options,
  .page-nav {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 1060px) {
  .practice-controls {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (max-width: 680px) {
  .practice-controls {
    grid-template-columns: 1fr;
  }

  .rewards-dashboard {
    grid-template-columns: 1fr;
  }
}