:root {
  color-scheme: dark;
  --bg: #0d0f12;
  --bg-soft: #14181d;
  --panel: rgba(24, 28, 34, 0.88);
  --panel-strong: #1b2026;
  --line: rgba(255, 214, 77, 0.18);
  --line-strong: rgba(255, 214, 77, 0.4);
  --text: #f7f2d9;
  --muted: #b8b29c;
  --accent: #ffd54d;
  --accent-strong: #ffbf1f;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
  font-family: "Outfit", "Noto Sans SC", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(255, 197, 61, 0.2), transparent 25%),
    radial-gradient(circle at bottom right, rgba(255, 214, 77, 0.12), transparent 20%),
    linear-gradient(145deg, #090b0d 0%, #11161a 46%, #0d1014 100%);
  color: var(--text);
}

body,
button,
input,
select {
  font: inherit;
}

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

button {
  border: 0;
  cursor: pointer;
}

.shell {
  display: grid;
  grid-template-columns: 320px 1fr;
  min-height: 100vh;
}

.sidebar {
  padding: 32px;
  border-right: 1px solid var(--line);
  background: rgba(10, 12, 15, 0.78);
  backdrop-filter: blur(18px);
}

.brand h1 {
  margin: 8px 0 12px;
  font-size: 2rem;
}

.brand-kicker {
  margin: 0;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.72rem;
}

.brand-copy {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.tab-nav {
  display: grid;
  gap: 12px;
  margin-top: 32px;
}

.tab-button {
  display: block;
  padding: 16px 18px;
  border-radius: 18px;
  text-align: left;
  background: var(--bg-soft);
  border: 1px solid transparent;
  transition: transform 180ms ease, border-color 180ms ease, background 180ms ease;
}

.tab-button:hover,
.tab-button.active {
  transform: translateY(-1px);
  background: rgba(255, 213, 77, 0.08);
  border-color: var(--line-strong);
}

.content {
  padding: 32px;
}

.page-grid,
.task-catalog,
.classroom-list,
.task-step-list,
.group-grid,
.stack-form {
  display: grid;
  gap: 16px;
}

.page-grid {
  gap: 24px;
}

.section-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 28px;
  padding: 24px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.section-card-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  margin-bottom: 20px;
}

.section-card-header h2 {
  margin: 0 0 6px;
  font-size: 1.35rem;
}

.section-card-header p,
.feedback,
.muted-note,
.meta-line,
.empty-state,
.catalog-item p,
.task-step p,
.group-card small,
.classroom-card-header p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

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

.stack-form span,
.inline-grid span {
  color: var(--muted);
  font-size: 0.92rem;
}

input,
select {
  width: 100%;
  padding: 14px 16px;
  border-radius: 16px;
  border: 1px solid var(--line);
  color: var(--text);
  background: rgba(7, 8, 11, 0.7);
  outline: none;
}

input:focus,
select:focus {
  border-color: var(--line-strong);
  box-shadow: 0 0 0 3px rgba(255, 213, 77, 0.12);
}

.inline-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.primary-button,
.ghost-button,
.inline-action {
  border-radius: 999px;
  padding: 12px 18px;
  font-weight: 600;
}

.primary-button {
  color: #241700;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-strong) 100%);
}

.ghost-button,
.inline-action {
  color: var(--text);
  background: rgba(255, 213, 77, 0.08);
  border: 1px solid var(--line);
}

.inline-action[disabled] {
  color: var(--muted);
  cursor: not-allowed;
  opacity: 0.6;
}

.highlight-pill,
.step-tag {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 6px 12px;
  background: rgba(255, 213, 77, 0.12);
  color: var(--accent);
  font-size: 0.85rem;
}

.catalog-item,
.classroom-card,
.group-card,
.task-step {
  background: var(--panel-strong);
  border: 1px solid rgba(255, 255, 255, 0.04);
  border-radius: 20px;
  padding: 18px;
}

.catalog-item h3,
.classroom-card h3,
.task-step h4 {
  margin: 0 0 8px;
}

.classroom-card-header {
  display: flex;
  gap: 12px;
  justify-content: space-between;
  align-items: center;
}

.group-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.group-card strong {
  display: block;
  margin-bottom: 14px;
}

.group-card ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 12px;
}

.group-card li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
}

.group-card li div {
  display: grid;
  gap: 4px;
}

.empty-state {
  padding: 24px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.03);
}

@media (max-width: 960px) {
  .shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
}

@media (max-width: 640px) {
  .content,
  .sidebar {
    padding: 20px;
  }

  .inline-grid,
  .section-card-header,
  .classroom-card-header,
  .group-card li {
    display: grid;
    grid-template-columns: 1fr;
  }
}