:root {
  color-scheme: dark;
  --bg: #0b0b0c;
  --panel: #141416;
  --panel-2: #1a1b1f;
  --line: rgba(255, 255, 255, 0.08);
  --text: #f5f5f2;
  --muted: #b9b9b2;
  --accent: #d8d4c8;
  --success: #7dd3a0;
  --danger: #ff8a8a;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

body {
  min-height: 100vh;
}

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

.shell {
  max-width: 1120px;
  margin: 0 auto;
  padding: 24px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 24px;
}

.brand {
  font-size: 24px;
  font-weight: 700;
}

.nav {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.nav a {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 10px 14px;
  color: var(--muted);
}

.hero,
.card,
.panel {
  background: linear-gradient(180deg, rgba(255,255,255,0.03), rgba(255,255,255,0.015));
  border: 1px solid var(--line);
  border-radius: 24px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.25);
}

.hero {
  padding: 32px;
  margin-bottom: 24px;
}

.hero h1,
.card h2,
.panel h2 {
  margin-top: 0;
}

.grid {
  display: grid;
  gap: 20px;
}

.grid-2 {
  grid-template-columns: 1.2fr 0.8fr;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.card,
.panel {
  padding: 24px;
}

.card-list {
  display: grid;
  gap: 16px;
}

.course-card,
.topic-card,
.lesson-card,
.asset-card {
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px;
  background: rgba(255,255,255,0.015);
}

.meta {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.6;
}

.btn {
  appearance: none;
  border: 1px solid var(--line);
  background: var(--accent);
  color: #111;
  border-radius: 999px;
  padding: 12px 18px;
  font-weight: 700;
  cursor: pointer;
}

.btn-secondary {
  background: transparent;
  color: var(--text);
}

.btn-danger {
  background: transparent;
  color: var(--danger);
  border-color: rgba(255, 138, 138, 0.25);
}

.stack {
  display: grid;
  gap: 16px;
}

.content-box {
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px;
  background: rgba(255,255,255,0.015);
  white-space: pre-wrap;
  line-height: 1.8;
}

.status {
  display: inline-block;
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  font-size: 13px;
}

.status.success {
  color: var(--success);
}

.output {
  margin-top: 16px;
  background: #101012;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 16px;
  overflow: auto;
  white-space: pre-wrap;
  word-break: break-word;
  color: #cfd7ff;
}

.hidden {
  display: none;
}

@media (max-width: 900px) {
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }

  .shell {
    padding: 16px;
  }

  .hero,
  .card,
  .panel {
    padding: 20px;
  }
}