:root {
  color-scheme: dark;
  --bg-1: #242424;
  --bg-2: #242424;
  --surface: #434343;
  --panel: #434343;
  --panel-strong: #575757;
  --ink: #fbfbfe;
  --muted: #888888;
  --accent: #ff7139;
  --accent-2: #45a1ff;
  --accent-3: #ff9c57;
  --danger: #d1523a;
  --border: #414141;
  --shadow: 0 18px 40px rgba(0, 0, 0, 0.35);
  --radius: 18px;
  --radius-sm: 12px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Trebuchet MS", "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg-1);
  min-height: 100vh;
}

h1,
h2,
h3,
.brand-title {
  font-family: "Palatino Linotype", "Book Antiqua", serif;
  letter-spacing: 0.4px;
}

.ambient {
  position: fixed;
  inset: 0;
  background: transparent;
  pointer-events: none;
  z-index: 0;
}

.app {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.app[hidden] {
  display: none;
}

.auth-gate {
  position: fixed;
  inset: 0;
  z-index: 5;
  display: grid;
  place-items: center;
  padding: 24px;
  background: rgba(0, 0, 0, 0.55);
}

.auth-gate.hidden {
  display: none;
}

.auth-card {
  width: min(460px, 100%);
  background: var(--panel);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  padding: 24px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 32px;
  gap: 20px;
  backdrop-filter: blur(4px);
}

.auth-status {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--accent), var(--accent-3));
  color: var(--ink);
  font-weight: 700;
  box-shadow: var(--shadow);
}

.brand-title {
  font-size: 20px;
  font-weight: 700;
}

.brand-sub {
  font-size: 13px;
  color: var(--muted);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.nav-btn {
  border: 1px solid transparent;
  background: transparent;
  padding: 8px 14px;
  border-radius: 999px;
  color: var(--muted);
  cursor: pointer;
  transition: all 0.2s ease;
}

.nav-btn.active,
.nav-btn:hover {
  background: var(--panel-strong);
  border-color: var(--border);
  color: var(--ink);
}

.status {
  font-size: 12px;
  color: var(--muted);
}

.main {
  padding: 10px 32px 40px;
  flex: 1;
}

.view {
  display: none;
  animation: fadeUp 0.5s ease forwards;
}

.view.active {
  display: block;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

.grid.two {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.panel {
  background: var(--panel);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 14px;
}

.field label {
  font-size: 13px;
  color: var(--muted);
}

input,
select,
textarea {
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid #5f5f5f;
  background: var(--panel-strong);
  color: var(--ink);
  font: inherit;
}

input:focus,
select:focus,
textarea:focus {
  outline: 2px solid rgba(255, 113, 57, 0.5);
  outline-offset: 1px;
}

textarea {
  min-height: 90px;
  resize: vertical;
}

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

.dropzone {
  position: relative;
  border: 1px dashed var(--border);
  border-radius: var(--radius-sm);
  padding: 18px;
  text-align: center;
  background: var(--surface);
  margin-bottom: 12px;
}

.dropzone.highlight {
  border-color: var(--accent);
  background: var(--panel-strong);
}

.dropzone input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

.dropzone label {
  cursor: pointer;
}

.segmented {
  display: flex;
  gap: 12px;
  font-size: 14px;
}

button {
  border: none;
  padding: 10px 16px;
  border-radius: 999px;
  cursor: pointer;
  font: inherit;
}

button.primary {
  background: var(--accent);
  color: var(--ink);
  box-shadow: var(--shadow);
}

button.ghost {
  background: var(--panel-strong);
  border: 1px solid #5f5f5f;
  color: var(--ink);
}

button.danger {
  background: var(--danger);
  color: var(--ink);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.lesson-list {
  display: grid;
  gap: 12px;
}

.lesson-card {
  display: grid;
  gap: 12px;
  padding: 16px;
  border-radius: var(--radius-sm);
  background: var(--panel);
  border: 1px solid var(--border);
  animation: fadeUp 0.5s ease both;
}

.lesson-meta {
  display: grid;
  gap: 4px;
}

.lesson-title {
  font-weight: 700;
}

.lesson-sub {
  font-size: 13px;
  color: var(--muted);
}

.lesson-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag {
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--panel-strong);
  font-size: 12px;
}

.lesson-actions,
.task-actions,
.result-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.notice {
  margin-top: 10px;
  font-size: 13px;
  color: var(--muted);
}

.error-list {
  margin-top: 8px;
  color: var(--danger);
  font-size: 13px;
  white-space: pre-line;
}

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

.player-actions {
  display: flex;
  gap: 10px;
}

.eyebrow {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1.6px;
  color: var(--muted);
}

.progress {
  margin: 18px 0 12px;
  height: 10px;
  border-radius: 999px;
  background: var(--panel-strong);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-3));
  width: 0;
}

.task-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 18px;
}

.task-nav button {
  width: 32px;
  height: 32px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface);
}

.task-nav button.active {
  background: var(--accent-2);
  color: var(--ink);
}

.task {
  background: var(--panel);
  border-radius: var(--radius-sm);
  padding: 18px;
  border: 1px solid var(--border);
  display: grid;
  gap: 14px;
}

.question-list {
  display: grid;
  gap: 12px;
}

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

.criteria-row {
  display: grid;
  grid-template-columns: 1fr 2fr 36px;
  gap: 12px;
  align-items: center;
  font-size: 13px;
}

.criteria-row input[type="range"] {
  width: 100%;
}

.task-feedback {
  margin-top: 10px;
  font-size: 14px;
}

.choice-list,
.checkbox-list {
  display: grid;
  gap: 8px;
}

.inline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.cloze-input {
  width: 120px;
  display: inline-block;
  margin: 0 6px;
}

.flashcard {
  background: var(--panel-strong);
  border-radius: var(--radius-sm);
  padding: 20px;
  min-height: 140px;
  display: grid;
  gap: 12px;
  align-content: center;
  text-align: center;
}

.result-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 16px;
}

.summary-tile {
  padding: 16px;
  border-radius: var(--radius-sm);
  background: var(--panel);
  border: 1px solid var(--border);
}

.result-details {
  display: grid;
  gap: 10px;
}

.result-row {
  padding: 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--panel);
  display: grid;
  gap: 8px;
}

.result-row.correct {
  border-left: 6px solid var(--accent-2);
}

.result-row.incorrect {
  border-left: 6px solid var(--danger);
}

.result-row.partial {
  border-left: 6px solid var(--accent-3);
}

.result-row.skipped {
  border-left: 6px solid var(--muted);
}

.filters {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
  margin-bottom: 16px;
}

.history-list {
  display: grid;
  gap: 10px;
}

.history-card {
  padding: 14px;
  border-radius: var(--radius-sm);
  background: var(--panel);
  border: 1px solid var(--border);
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 12px;
  align-items: center;
}

.history-score {
  font-weight: 700;
}

.analytics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.stat-card {
  background: var(--panel);
  border-radius: var(--radius-sm);
  padding: 16px;
  border: 1px solid var(--border);
  min-height: 160px;
}

.result-actions {
  margin-bottom: 16px;
}

@media (max-width: 900px) {
  .topbar {
    flex-direction: column;
    align-items: flex-start;
  }

  .nav {
    width: 100%;
  }

  .history-card {
    grid-template-columns: 1fr;
    justify-items: start;
  }
}