/* ── ClassBridge Design System ── */
/* Matches landing page design tokens */

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

:root {
  --ink: #0f1729;
  --slate: #3d4663;
  --mist: #8892b0;
  --cloud: #f0f2f8;
  --white: #ffffff;
  --amber: #f59e0b;
  --amber-light: #fef3c7;
  --teal: #0d9488;
  --teal-light: #ccfbf1;
  --violet: #7c3aed;
  --violet-light: #ede9fe;
  --danger: #ef4444;
  --danger-light: #fef2f2;
}

body {
  font-family: 'Plus Jakarta Sans', -apple-system, sans-serif;
  color: var(--ink);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: 'Space Grotesk', sans-serif;
  letter-spacing: -0.02em;
}

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

/* ── Layout ── */
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.page-bg {
  min-height: 100vh;
  background: linear-gradient(165deg, #f8f6ff 0%, #fffbeb 40%, #f0fdfa 100%);
}

/* ── App Header ── */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  background: var(--white);
  border-bottom: 1px solid var(--cloud);
  position: sticky;
  top: 0;
  z-index: 100;
}

.app-logo {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--ink);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 10px;
}
.app-logo:hover { text-decoration: none; }

.logo-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--violet) 0%, var(--teal) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 13px;
  font-weight: 700;
  flex-shrink: 0;
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 12px;
  font-family: 'Plus Jakarta Sans', sans-serif;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
  text-decoration: none;
  line-height: 1.2;
}
.btn:hover { text-decoration: none; }

.btn-primary { background: var(--violet); color: white; }
.btn-primary:hover { background: #6d28d9; }

.btn-teal { background: var(--teal); color: white; }
.btn-teal:hover { background: #0f766e; }

.btn-outline { background: transparent; border: 2px solid var(--cloud); color: var(--slate); }
.btn-outline:hover { border-color: var(--violet); color: var(--violet); }

.btn-danger { background: var(--danger); color: white; }
.btn-danger:hover { background: #dc2626; }

.btn-ghost { background: transparent; color: var(--slate); }
.btn-ghost:hover { background: var(--cloud); }

.btn-sm { padding: 8px 16px; font-size: 13px; border-radius: 10px; }
.btn-lg { padding: 16px 32px; font-size: 17px; }
.btn-block { width: 100%; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

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

.form-label {
  display: block;
  font-weight: 600;
  font-size: 14px;
  color: var(--slate);
  margin-bottom: 6px;
}

.form-input, .form-select {
  width: 100%;
  padding: 12px 16px;
  border: 2px solid var(--cloud);
  border-radius: 12px;
  font-family: 'Plus Jakarta Sans', sans-serif;
  font-size: 15px;
  color: var(--ink);
  background: var(--white);
  transition: border-color 0.2s;
  outline: none;
}

.form-input:focus, .form-select:focus { border-color: var(--violet); }
.form-input::placeholder { color: var(--mist); }

/* ── Cards ── */
.card {
  background: var(--white);
  border-radius: 16px;
  border: 1px solid rgba(0,0,0,0.06);
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
  overflow: hidden;
}

.card-body { padding: 24px; }

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

.stat-card {
  background: var(--white);
  border-radius: 16px;
  padding: 24px;
  border: 1px solid rgba(0,0,0,0.06);
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}

.stat-value {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 2rem;
  font-weight: 700;
}

.stat-label {
  font-size: 14px;
  color: var(--mist);
  margin-top: 4px;
}

/* ── Chat ── */
.chat-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  height: 100dvh;
}

.chat-header {
  padding: 14px 24px;
  background: var(--white);
  border-bottom: 1px solid var(--cloud);
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  background: linear-gradient(165deg, #f8f6ff 0%, #fffbeb 40%, #f0fdfa 100%);
}

.chat-input-area {
  padding: 12px 16px;
  background: var(--white);
  border-top: 1px solid var(--cloud);
  display: flex;
  gap: 10px;
  flex-shrink: 0;
}

.chat-input {
  flex: 1;
  padding: 14px 18px;
  border: 2px solid var(--cloud);
  border-radius: 14px;
  font-size: 15px;
  font-family: 'Plus Jakarta Sans', sans-serif;
  outline: none;
  resize: none;
  color: var(--ink);
}
.chat-input:focus { border-color: var(--violet); }
.chat-input::placeholder { color: var(--mist); }

.chat-send {
  padding: 14px 20px;
  border-radius: 14px;
  background: var(--violet);
  color: white;
  border: none;
  cursor: pointer;
  font-weight: 700;
  font-size: 15px;
  font-family: 'Plus Jakarta Sans', sans-serif;
  transition: background 0.2s;
  flex-shrink: 0;
}
.chat-send:hover { background: #6d28d9; }
.chat-send:disabled { opacity: 0.5; cursor: not-allowed; }

.message {
  max-width: 80%;
  padding: 14px 18px;
  border-radius: 16px;
  font-size: 15px;
  line-height: 1.65;
  animation: msgFadeIn 0.3s ease;
  word-wrap: break-word;
}

@keyframes msgFadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.message.student {
  background: var(--violet);
  color: white;
  align-self: flex-end;
  border-bottom-right-radius: 4px;
}

.message.assistant {
  background: var(--white);
  color: var(--ink);
  border: 1px solid rgba(0,0,0,0.06);
  align-self: flex-start;
  border-bottom-left-radius: 4px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}

.message.assistant strong,
.message.assistant b {
  color: var(--violet);
  font-weight: 700;
}

/* Typing indicator */
.typing-indicator {
  display: flex;
  gap: 5px;
  padding: 16px 20px;
  align-self: flex-start;
  background: var(--white);
  border-radius: 16px;
  border-bottom-left-radius: 4px;
  border: 1px solid rgba(0,0,0,0.06);
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
  animation: msgFadeIn 0.3s ease;
}

.typing-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--mist);
  animation: typingBounce 1.4s ease-in-out infinite;
}
.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingBounce {
  0%, 60%, 100% { transform: translateY(0); }
  30% { transform: translateY(-6px); }
}

/* ── Grids ── */
.classroom-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
}

/* ── Tables ── */
.data-table {
  width: 100%;
  border-collapse: collapse;
}

.data-table th {
  text-align: left;
  padding: 12px 16px;
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--mist);
  border-bottom: 2px solid var(--cloud);
}

.data-table td {
  padding: 12px 16px;
  font-size: 14px;
  border-bottom: 1px solid var(--cloud);
}

.data-table tr:hover td { background: rgba(124,58,237,0.02); }
.data-table tr { cursor: pointer; }

/* ── Modal ── */
.modal-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(15,23,41,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: all 0.2s;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--white);
  border-radius: 20px;
  padding: 32px;
  width: 90%;
  max-width: 480px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.2);
  transform: scale(0.95);
  transition: transform 0.2s;
}

.modal-overlay.active .modal {
  transform: scale(1);
}

/* ── Badges ── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 600;
  white-space: nowrap;
}

.badge-violet { background: var(--violet-light); color: var(--violet); }
.badge-teal { background: var(--teal-light); color: var(--teal); }
.badge-amber { background: var(--amber-light); color: #b45309; }

/* ── Join Code ── */
.join-code-display {
  font-family: 'Space Grotesk', monospace;
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--violet);
  background: var(--violet-light);
  padding: 16px 32px;
  border-radius: 16px;
  display: inline-block;
  user-select: all;
}

/* ── Empty States ── */
.empty-state {
  text-align: center;
  padding: 48px 24px;
  color: var(--mist);
}

.empty-state-icon {
  font-size: 3rem;
  margin-bottom: 12px;
}

.empty-state h3 {
  font-size: 1.1rem;
  color: var(--slate);
  margin-bottom: 8px;
}

/* ── Language Selector ── */
.language-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.language-option {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  border: 2px solid var(--cloud);
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s;
  background: var(--white);
}

.language-option:hover { border-color: var(--violet); }
.language-option.selected {
  border-color: var(--violet);
  background: var(--violet-light);
}

.language-option input[type="radio"] { display: none; }
.lang-flag { font-size: 1.4rem; }
.lang-name { font-weight: 600; font-size: 14px; }

/* ── Session Transcript ── */
.transcript {
  padding: 20px;
  background: var(--cloud);
  border-radius: 12px;
  margin-top: 12px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-height: 400px;
  overflow-y: auto;
}

.transcript-msg {
  max-width: 85%;
  padding: 10px 14px;
  border-radius: 12px;
  font-size: 14px;
  line-height: 1.55;
}

.transcript-msg.student {
  background: var(--violet);
  color: white;
  align-self: flex-end;
  border-bottom-right-radius: 4px;
}

.transcript-msg.assistant {
  background: var(--white);
  border: 1px solid rgba(0,0,0,0.06);
  align-self: flex-start;
  border-bottom-left-radius: 4px;
}

.transcript-msg.assistant strong { color: var(--violet); }

/* ── Tabs ── */
.tab-bar {
  display: flex;
  gap: 4px;
  background: var(--cloud);
  border-radius: 10px;
  padding: 4px;
}

.tab-btn {
  flex: 1;
  padding: 10px;
  border: none;
  border-radius: 8px;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s;
  font-family: 'Plus Jakarta Sans', sans-serif;
  background: transparent;
  color: var(--slate);
}

.tab-btn.active {
  background: var(--white);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  color: var(--ink);
}

/* ── Utilities ── */
.text-mist { color: var(--mist); }
.text-slate { color: var(--slate); }
.text-violet { color: var(--violet); }
.text-teal { color: var(--teal); }
.text-amber { color: var(--amber); }
.text-sm { font-size: 13px; }
.text-center { text-align: center; }
.mt-4 { margin-top: 16px; }
.mt-8 { margin-top: 32px; }
.mt-10 { margin-top: 40px; }
.mb-4 { margin-top: 16px; }
.flex { display: flex; }
.gap-2 { gap: 8px; }
.gap-3 { gap: 12px; }
.gap-4 { gap: 16px; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }

/* ── Responsive ── */
@media (max-width: 640px) {
  .container { padding: 0 16px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .classroom-grid { grid-template-columns: 1fr; }
  .language-grid { grid-template-columns: 1fr; }
  .message { max-width: 90%; }
  .modal { padding: 24px; width: 95%; }
  .app-header { padding: 12px 16px; }
  .btn-lg { padding: 14px 24px; font-size: 15px; }
  .join-code-display { font-size: 1.8rem; padding: 12px 24px; }
  .data-table th, .data-table td { padding: 10px 12px; }
}