:root {
  --bg: #eef3f8;
  --panel: #ffffff;
  --ink: #182230;
  --muted: #667085;
  --line: #d8e2ed;
  --accent: #0f766e;
  --accent-strong: #0a5d57;
  --blue: #2563eb;
  --red: #b42318;
  --green: #087443;
  --amber: #b45309;
  --shadow: 0 22px 60px rgba(24, 34, 48, 0.14);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  letter-spacing: 0;
}

button,
input {
  font: inherit;
}

.deck-shell {
  width: min(1180px, calc(100% - 40px));
  min-height: 100vh;
  margin: 0 auto;
  padding: 28px 0;
  display: grid;
  grid-template-rows: auto auto minmax(520px, 1fr) auto;
  gap: 18px;
}

.topbar,
.slide-stage,
.deck-controls,
.deck-progress {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: center;
  padding: 22px 26px;
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: 28px;
}

.course-rules {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: flex-end;
}

.course-rules span {
  min-height: 34px;
  display: inline-flex;
  align-items: center;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
  color: var(--muted);
  font-size: 13px;
  white-space: nowrap;
}

.deck-progress {
  padding: 14px 18px;
}

.progress-meta {
  display: flex;
  justify-content: space-between;
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 14px;
}

.progress-track {
  height: 10px;
  overflow: hidden;
  background: #e7edf5;
  border-radius: 999px;
}

.progress-fill {
  width: 0;
  height: 100%;
  background: var(--accent);
  transition: width 180ms ease;
}

.slide-stage {
  overflow: hidden;
}

.slide {
  min-height: 520px;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, 0.9fr);
  gap: 28px;
  align-items: center;
  padding: 36px;
}

.slide.quiz-slide {
  display: block;
}

.slide-copy h2 {
  margin-bottom: 14px;
  font-size: 34px;
  line-height: 1.15;
}

.slide-copy p,
.slide-copy li,
.quiz-card p {
  color: var(--muted);
  line-height: 1.55;
}

.slide-copy ul {
  margin: 18px 0 0;
  padding-left: 20px;
}

.hero-note {
  margin-top: 22px;
  padding: 16px;
  border-left: 4px solid var(--accent);
  background: #eefaf8;
  border-radius: 8px;
  color: #134e4a;
}

.visual-card {
  min-height: 360px;
  display: grid;
  align-content: center;
  justify-items: center;
  gap: 18px;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
}

.visual-card img {
  width: min(100%, 330px);
  height: auto;
  display: block;
}

.visual-card strong {
  text-align: center;
  font-size: 18px;
}

.practice-card,
.quiz-card {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfdff;
}

.practice-card h3,
.quiz-card h3 {
  margin-bottom: 16px;
}

.choice-grid {
  display: grid;
  gap: 10px;
}

.choice {
  display: grid;
  grid-template-columns: 20px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  cursor: pointer;
}

.choice.correct {
  border-color: rgba(8, 116, 67, 0.42);
  background: #ecfdf3;
}

.choice.wrong {
  border-color: rgba(180, 35, 24, 0.42);
  background: #fff1f0;
}

.feedback {
  margin-top: 14px;
  padding: 13px;
  border-radius: 8px;
  background: #eef6ff;
  color: #1849a9;
}

.quiz-grid {
  display: grid;
  gap: 16px;
}

.quiz-card h3 {
  font-size: 18px;
}

.quiz-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

.result-panel {
  margin-top: 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
}

.result-panel.pass {
  border-color: rgba(8, 116, 67, 0.42);
  background: #ecfdf3;
}

.result-panel.fail {
  border-color: rgba(180, 35, 24, 0.42);
  background: #fff1f0;
}

.deck-controls {
  display: flex;
  justify-content: space-between;
  padding: 16px;
}

.primary-btn,
.secondary-btn {
  min-height: 44px;
  padding: 10px 18px;
  border-radius: 8px;
  cursor: pointer;
}

.primary-btn {
  border: 1px solid var(--accent-strong);
  background: var(--accent);
  color: #ffffff;
}

.secondary-btn {
  border: 1px solid var(--line);
  background: #ffffff;
  color: var(--ink);
}

.primary-btn:disabled,
.secondary-btn:disabled {
  opacity: 0.52;
  cursor: not-allowed;
}

@media (max-width: 860px) {
  .deck-shell {
    width: min(100% - 24px, 1180px);
  }

  .topbar,
  .slide {
    grid-template-columns: 1fr;
  }

  .topbar {
    display: grid;
  }

  .course-rules {
    justify-content: flex-start;
  }

  .slide {
    padding: 24px;
  }
}

@media (max-width: 560px) {
  .deck-shell {
    grid-template-rows: auto auto minmax(420px, 1fr) auto;
  }

  h1 {
    font-size: 22px;
  }

  .slide-copy h2 {
    font-size: 26px;
  }

  .visual-card {
    min-height: 240px;
  }
}