/* ===== LearnHive App Styles ===== */
/* Design system matches landing page: dark bg + amber accent */

* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --bg: #0a0a0f;
  --surface: #12121a;
  --surface-2: #1a1a26;
  --surface-3: #222233;
  --amber: #f5a623;
  --amber-dim: rgba(245, 166, 35, 0.12);
  --amber-glow: rgba(245, 166, 35, 0.06);
  --amber-hover: #e6991a;
  --green: #34d399;
  --green-dim: rgba(52, 211, 153, 0.15);
  --red: #f87171;
  --red-dim: rgba(248, 113, 113, 0.15);
  --blue: #60a5fa;
  --text: #e8e6e3;
  --text-dim: #8a8892;
  --text-muted: #5a5868;
  --border: rgba(255,255,255,0.06);
  --border-hover: rgba(255,255,255,0.12);
  --radius: 12px;
  --radius-lg: 20px;
}

body {
  font-family: 'DM Sans', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

h1, h2, h3, h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 600;
  line-height: 1.2;
}

a { color: var(--amber); text-decoration: none; }
a:hover { color: var(--amber-hover); }

/* ===== Layout ===== */
.app-container {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 240px;
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 24px 16px;
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 100;
}

.sidebar-logo {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 700;
  font-size: 1.3rem;
  color: var(--amber);
  padding: 0 8px 24px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 24px;
}

.sidebar-logo .dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  background: var(--amber);
  border-radius: 50%;
  margin-left: 1px;
  vertical-align: super;
}

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 8px;
  color: var(--text-dim);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.15s;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
}

.nav-item:hover {
  background: var(--surface-2);
  color: var(--text);
}

.nav-item.active {
  background: var(--amber-dim);
  color: var(--amber);
}

.nav-item svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.sidebar-footer {
  border-top: 1px solid var(--border);
  padding-top: 16px;
}

.user-info {
  font-size: 0.8rem;
  color: var(--text-dim);
  padding: 0 8px;
  margin-bottom: 8px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.main-content {
  flex: 1;
  margin-left: 240px;
  padding: 32px 40px;
  max-width: 960px;
}

/* ===== Auth Pages ===== */
.auth-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 24px;
}

.auth-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
  width: 100%;
  max-width: 420px;
}

.auth-card h1 {
  font-size: 1.8rem;
  margin-bottom: 8px;
  letter-spacing: -0.5px;
}

.auth-card .subtitle {
  color: var(--text-dim);
  margin-bottom: 32px;
  font-size: 0.95rem;
}

/* ===== Forms ===== */
.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-bottom: 6px;
  font-weight: 500;
}

.form-input {
  width: 100%;
  padding: 12px 16px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 0.95rem;
  font-family: 'DM Sans', sans-serif;
  transition: border-color 0.15s;
  outline: none;
}

.form-input:focus {
  border-color: var(--amber);
}

.form-input::placeholder {
  color: var(--text-muted);
}

textarea.form-input {
  min-height: 200px;
  resize: vertical;
  line-height: 1.6;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 500;
  font-family: 'DM Sans', sans-serif;
  cursor: pointer;
  transition: all 0.15s;
  border: 1px solid transparent;
  text-decoration: none;
}

.btn-primary {
  background: var(--amber);
  color: var(--bg);
  border-color: var(--amber);
}

.btn-primary:hover {
  background: var(--amber-hover);
  border-color: var(--amber-hover);
  color: var(--bg);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-secondary {
  background: var(--surface-2);
  color: var(--text);
  border-color: var(--border);
}

.btn-secondary:hover {
  border-color: var(--border-hover);
  background: var(--surface-3);
}

.btn-ghost {
  background: transparent;
  color: var(--text-dim);
  border: none;
  padding: 8px 12px;
}

.btn-ghost:hover {
  color: var(--text);
}

.btn-block {
  width: 100%;
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.85rem;
}

/* ===== Page Headers ===== */
.page-header {
  margin-bottom: 32px;
}

.page-header h1 {
  font-size: 1.8rem;
  letter-spacing: -0.5px;
  margin-bottom: 6px;
}

.page-header p {
  color: var(--text-dim);
  font-size: 0.95rem;
}

/* ===== Cards ===== */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin-bottom: 20px;
  transition: border-color 0.2s;
}

.card:hover {
  border-color: var(--border-hover);
}

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

.card-title {
  font-size: 1.1rem;
  font-weight: 600;
}

/* ===== Stats Grid ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
}

.stat-value {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 2rem;
  font-weight: 700;
  color: var(--amber);
  letter-spacing: -1px;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-dim);
  margin-top: 4px;
}

/* ===== Upload Area ===== */
.upload-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  padding: 48px;
  text-align: center;
  transition: all 0.2s;
  cursor: pointer;
  background: var(--surface);
}

.upload-zone:hover,
.upload-zone.dragover {
  border-color: var(--amber);
  background: var(--amber-glow);
}

.upload-zone svg {
  width: 48px;
  height: 48px;
  color: var(--text-dim);
  margin-bottom: 16px;
}

.upload-zone h3 {
  font-size: 1.2rem;
  margin-bottom: 8px;
}

.upload-zone p {
  color: var(--text-dim);
  font-size: 0.9rem;
}

.upload-or {
  color: var(--text-muted);
  margin: 24px 0;
  font-size: 0.85rem;
  position: relative;
}

.upload-or::before,
.upload-or::after {
  content: '';
  position: absolute;
  top: 50%;
  width: 80px;
  height: 1px;
  background: var(--border);
}

.upload-or::before { right: calc(50% + 20px); }
.upload-or::after { left: calc(50% + 20px); }

/* ===== Study Plan Items ===== */
.plan-date-group {
  margin-bottom: 24px;
}

.plan-date-label {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--amber);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.plan-date-label.today {
  color: var(--amber);
}

.plan-date-label.past {
  color: var(--text-muted);
}

.plan-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 8px;
  transition: all 0.15s;
}

.plan-item:hover {
  border-color: var(--border-hover);
}

.plan-item.completed {
  opacity: 0.5;
}

.plan-item.completed .plan-item-title {
  text-decoration: line-through;
}

.plan-checkbox {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-hover);
  border-radius: 50%;
  cursor: pointer;
  flex-shrink: 0;
  margin-top: 2px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}

.plan-checkbox:hover {
  border-color: var(--amber);
}

.plan-checkbox.checked {
  background: var(--amber);
  border-color: var(--amber);
}

.plan-checkbox.checked::after {
  content: '✓';
  color: var(--bg);
  font-size: 12px;
  font-weight: 700;
}

.plan-item-content {
  flex: 1;
}

.plan-item-title {
  font-weight: 500;
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.plan-item-meta {
  font-size: 0.8rem;
  color: var(--text-dim);
  display: flex;
  gap: 12px;
}

.plan-item-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.7rem;
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.badge-learn { background: var(--amber-dim); color: var(--amber); }
.badge-review { background: rgba(96, 165, 250, 0.15); color: var(--blue); }
.badge-practice { background: var(--green-dim); color: var(--green); }

/* ===== Quiz ===== */
.quiz-container {
  max-width: 640px;
}

.quiz-progress {
  display: flex;
  gap: 6px;
  margin-bottom: 32px;
}

.quiz-progress-dot {
  flex: 1;
  height: 4px;
  border-radius: 2px;
  background: var(--surface-2);
}

.quiz-progress-dot.answered { background: var(--amber); }
.quiz-progress-dot.current { background: var(--amber-dim); }

.quiz-question {
  font-size: 1.15rem;
  font-weight: 500;
  margin-bottom: 24px;
  line-height: 1.5;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}

.quiz-option {
  padding: 16px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.15s;
  font-size: 0.95rem;
  text-align: left;
  color: var(--text);
  font-family: 'DM Sans', sans-serif;
}

.quiz-option:hover:not(.disabled) {
  border-color: var(--amber);
  background: var(--amber-glow);
}

.quiz-option.selected {
  border-color: var(--amber);
  background: var(--amber-dim);
}

.quiz-option.correct {
  border-color: var(--green);
  background: var(--green-dim);
}

.quiz-option.incorrect {
  border-color: var(--red);
  background: var(--red-dim);
}

.quiz-option.disabled {
  cursor: default;
}

.quiz-explanation {
  padding: 16px 20px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 20px;
  font-size: 0.9rem;
  color: var(--text-dim);
  line-height: 1.6;
}

.quiz-explanation strong {
  color: var(--text);
}

.quiz-result {
  text-align: center;
  padding: 40px;
}

.quiz-score {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--amber);
  letter-spacing: -2px;
  margin-bottom: 8px;
}

.quiz-score-label {
  color: var(--text-dim);
  font-size: 1rem;
  margin-bottom: 32px;
}

/* ===== Topics List ===== */
.topic-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 8px;
}

.topic-name {
  font-weight: 500;
}

.topic-meta {
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* ===== Loading / Empty States ===== */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 60px;
  color: var(--text-dim);
}

.spinner {
  width: 24px;
  height: 24px;
  border: 3px solid var(--surface-2);
  border-top-color: var(--amber);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  margin-right: 12px;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.empty-state {
  text-align: center;
  padding: 60px 24px;
  color: var(--text-dim);
}

.empty-state h3 {
  color: var(--text);
  margin-bottom: 8px;
}

.empty-state p {
  margin-bottom: 24px;
  font-size: 0.95rem;
}

/* ===== Alerts ===== */
.alert {
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.alert-error {
  background: var(--red-dim);
  color: var(--red);
  border: 1px solid rgba(248, 113, 113, 0.2);
}

.alert-success {
  background: var(--green-dim);
  color: var(--green);
  border: 1px solid rgba(52, 211, 153, 0.2);
}

/* ===== Parsing Animation ===== */
.parsing-status {
  text-align: center;
  padding: 60px 24px;
}

.parsing-status h2 {
  margin-bottom: 16px;
}

.parsing-steps {
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: 400px;
  margin: 24px auto;
  text-align: left;
}

.parsing-step {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-dim);
}

.parsing-step.active {
  color: var(--amber);
}

.parsing-step.done {
  color: var(--green);
}

.parsing-step-icon {
  width: 20px;
  text-align: center;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .sidebar {
    display: none;
  }

  .main-content {
    margin-left: 0;
    padding: 20px;
  }

  .mobile-nav {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 8px 0;
    z-index: 100;
    justify-content: space-around;
  }

  .mobile-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 8px 12px;
    color: var(--text-dim);
    font-size: 0.7rem;
    background: none;
    border: none;
    cursor: pointer;
  }

  .mobile-nav-item.active {
    color: var(--amber);
  }

  .mobile-nav-item svg {
    width: 20px;
    height: 20px;
  }

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

  .auth-card {
    padding: 32px 24px;
  }

  body {
    padding-bottom: 80px;
  }
}

@media (min-width: 769px) {
  .mobile-nav { display: none; }
}

/* ===== Utility ===== */
.text-center { text-align: center; }
.text-dim { color: var(--text-dim); }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }
.flex { display: flex; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.gap-8 { gap: 8px; }
.gap-12 { gap: 12px; }
.hidden { display: none !important; }