:root {
  color-scheme: dark;
  --bg: #031423;
  --panel: rgba(6, 29, 49, 0.86);
  --panel-strong: #07253e;
  --text: #f4f8fc;
  --muted: #9eb5c7;
  --accent: #005BA4;
  --accent-2: #0C6FC6;
  --accent-soft: #7FB9D9;
  --success: #2ea67f;
  --border: rgba(127, 185, 217, 0.18);
  --shadow: 0 24px 50px rgba(0, 18, 32, 0.28);
}

:root[data-theme="light"] {
  color-scheme: light;
  --bg: #f4f8fc;
  --panel: rgba(255, 255, 255, 0.92);
  --panel-strong: #ffffff;
  --text: #07253e;
  --muted: #4e657c;
  --accent: #005BA4;
  --accent-2: #0C6FC6;
  --accent-soft: #dceefc;
  --success: #2ea67f;
  --border: rgba(0, 91, 164, 0.12);
  --shadow: 0 20px 40px rgba(0, 91, 164, 0.10);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(98, 208, 255, 0.16), transparent 30%),
    radial-gradient(circle at top right, rgba(124, 77, 255, 0.15), transparent 30%),
    var(--bg);
  color: var(--text);
  min-height: 100vh;
}

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

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

#app {
  min-height: 100vh;
}

.shell {
  display: grid;
  grid-template-columns: 280px 1fr;
  min-height: 100vh;
}

.sidebar {
  padding: 24px 20px;
  border-right: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.03);
  backdrop-filter: blur(20px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
}

.logo {
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  font-weight: 700;
  color: white;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.22);
}

.brand h1 {
  font-size: 1rem;
  margin: 0;
}

.brand p {
  margin: 2px 0 0;
  color: var(--muted);
  font-size: 0.8rem;
}

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

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 11px 12px;
  border: 0;
  border-radius: 12px;
  background: transparent;
  color: var(--text);
  text-align: left;
}

.nav-item.active,
.nav-item:hover {
  background: rgba(98, 208, 255, 0.12);
}

.main {
  padding: 24px;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
}

.search-box {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--panel);
  box-shadow: var(--shadow);
}

.search-box input {
  flex: 1;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--text);
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.ghost-btn,
.primary-btn,
.secondary-btn {
  border: 0;
  border-radius: 999px;
  padding: 10px 14px;
  font-weight: 600;
}

.primary-btn {
  color: white;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
}

.secondary-btn {
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border);
}

.ghost-btn {
  background: transparent;
  color: var(--muted);
}

.hero {
  display: grid;
  grid-template-columns: 1.4fr 0.8fr;
  gap: 20px;
  margin-bottom: 20px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 24px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(20px);
}

.hero-card {
  padding: 24px;
}

.hero-card h2 {
  font-size: 1.6rem;
  margin: 0 0 8px;
}

.hero-card p {
  color: var(--muted);
  margin: 0 0 14px;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border-radius: 999px;
  background: rgba(12, 111, 198, 0.14);
  color: var(--text);
  font-size: 0.85rem;
}

.progress-card {
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.progress-ring {
  width: 110px;
  height: 110px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: conic-gradient(var(--accent) 0 64%, rgba(148, 163, 184, 0.18) 64% 100%);
  margin-bottom: 12px;
}

.progress-ring span {
  width: 82px;
  height: 82px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--panel-strong);
  font-size: 1.2rem;
  font-weight: 700;
}

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

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

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.section-card {
  padding: 20px;
}

.section-title {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

.section-title h3 {
  margin: 0;
  font-size: 1rem;
}

.muted {
  color: var(--muted);
}

.language-list,
.lesson-list,
.module-list,
.resource-list {
  display: grid;
  gap: 10px;
}

.language-card,
.lesson-item,
.module-item,
.resource-item {
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 14px;
  background: rgba(255, 255, 255, 0.03);
}

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

.language-card strong,
.lesson-item strong,
.module-item strong {
  display: block;
  margin-bottom: 5px;
}

.language-card .meta,
.lesson-item .meta,
.module-item .meta {
  color: var(--muted);
  font-size: 0.92rem;
}

.language-card .pill,
.lesson-item .pill {
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(12, 111, 198, 0.14);
  font-size: 0.82rem;
  color: var(--accent-2);
}

.lesson-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.lesson-item .actions {
  display: flex;
  gap: 8px;
}

.breadcrumb {
  color: var(--muted);
  margin-bottom: 12px;
}

.page-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
}

.page-head h2 {
  margin: 0;
}

.video-shell {
  padding: 20px;
  margin-bottom: 16px;
  border-radius: 24px;
  background: linear-gradient(135deg, rgba(98, 208, 255, 0.16), rgba(124, 77, 255, 0.16));
  border: 1px solid var(--border);
}

.video-frame {
  min-height: 280px;
  border-radius: 20px;
  border: 1px solid var(--border);
  background: linear-gradient(135deg, rgba(2, 6, 23, 0.95), rgba(30, 41, 59, 0.92));
  display: grid;
  place-items: center;
  position: relative;
  overflow: hidden;
}

.video-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent, rgba(98, 208, 255, 0.2));
}

.video-frame button {
  position: relative;
  z-index: 1;
  padding: 14px 18px;
  border-radius: 999px;
  border: 0;
  background: white;
  color: #0f172a;
  font-weight: 700;
}

.lesson-columns {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 16px;
}

.list-row {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  margin-top: 8px;
}

.auth-screen {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.auth-card {
  width: min(480px, 100%);
  padding: 30px;
  border-radius: 28px;
  background: var(--panel);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.auth-card h2 {
  margin-top: 0;
  margin-bottom: 8px;
}

.auth-card p {
  color: var(--muted);
}

.empty-state {
  padding: 16px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.03);
  color: var(--muted);
}

@media (max-width: 980px) {
  .shell {
    grid-template-columns: 1fr;
  }

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

  .hero,
  .lesson-columns,
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .main {
    padding: 16px;
  }

  .topbar {
    flex-direction: column;
    align-items: stretch;
  }

  .topbar-actions {
    justify-content: space-between;
  }

  .language-card,
  .lesson-item,
  .list-row {
    flex-direction: column;
    align-items: flex-start;
  }
}