/* =========================================================
   Typiqa — dark theme styling
   ========================================================= */

:root {
  --bg: #0a0a0b;
  --bg-elev: #141416;
  --bg-elev-2: #1d1d20;
  --border: #26262a;
  --border-strong: #3a3a3f;
  --text: #f4f4f5;
  --text-dim: #a1a1aa;
  --text-mute: #6c6c74;
  --primary: #f4f4f5;
  --primary-strong: #ffffff;
  --primary-fg: #0a0a0b;
  --accent: #a1a1aa;
  --hover-tint: rgba(255, 255, 255, 0.06);
  --hover-tint-strong: rgba(255, 255, 255, 0.10);
  --success: #4ade80;
  --danger: #f87171;
  --warn: #fbbf24;
  --code-bg: #08080a;
  --code-border: #232327;
  --radius: 10px;
  --radius-sm: 6px;
  --shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", Menlo, Consolas, "Courier New", monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
}

.mobile-only { display: none; }

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

img { max-width: 100%; }

.hidden { display: none !important; }
.muted { color: var(--text-dim); }
.small { font-size: 0.85rem; }

/* ===== Topbar ===== */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 28px;
  border-bottom: 1px solid var(--border);
  background: rgba(10, 10, 11, 0.75);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 600;
  font-size: 1.05rem;
}
.brand:hover { text-decoration: none; }

.brand-mark {
  color: var(--primary);
  font-size: 1.3rem;
}
.brand-name { letter-spacing: 0.02em; }

.topbar-nav {
  display: flex;
  align-items: center;
  gap: 12px;
}

.lang-toggle {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: inherit;
  font-size: 0.85rem;
}
.lang-toggle:hover { border-color: var(--border-strong); color: var(--text); }
.lang-toggle .active { color: var(--primary); font-weight: 600; }
.lang-toggle .lang-sep { color: var(--text-mute); margin: 0 2px; }

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 8px 16px;
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, transform 0.05s;
  text-decoration: none;
  white-space: nowrap;
}
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px); }

.btn-primary {
  background: var(--primary);
  color: var(--primary-fg);
  border-color: var(--primary);
}
.btn-primary:hover { background: var(--primary-strong); border-color: var(--primary-strong); }

.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}
.btn-ghost:hover { border-color: var(--border-strong); background: var(--bg-elev); }

.btn-lg { padding: 12px 22px; font-size: 1rem; }
.btn-sm { padding: 4px 10px; font-size: 0.8rem; }
.btn-block { width: 100%; }

/* ===== Landing ===== */
.page-landing main { max-width: 1080px; margin: 0 auto; padding: 32px 28px 80px; }

.hero {
  padding: 64px 0 56px;
  text-align: center;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  line-height: 1.1;
  margin: 0 0 18px;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #ffffff 0%, #a1a1aa 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero .lead {
  font-size: 1.1rem;
  max-width: 680px;
  margin: 0 auto 32px;
  color: var(--text-dim);
}
.hero-cta {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin: 24px 0 64px;
}
.feature {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}
.feature-icon { font-size: 1.8rem; margin-bottom: 8px; }
.feature h3 { margin: 0 0 6px; font-size: 1.05rem; }
.feature p { margin: 0; color: var(--text-dim); font-size: 0.95rem; }

.curriculum h2 { font-size: 1.8rem; margin: 0 0 6px; }
.curriculum-list { margin-top: 24px; display: flex; flex-direction: column; gap: 18px; }

.module-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}
.module-card h3 { margin: 0 0 4px; font-size: 1.15rem; }
.module-card .module-summary { color: var(--text-dim); margin: 0 0 14px; font-size: 0.95rem; }
.module-card .lesson-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0;
  border-top: 1px dashed var(--border);
}
.module-card .lesson-row:first-of-type { border-top: none; }
.module-card .lesson-title { flex: 1; }
.module-card .lesson-duration {
  color: var(--text-mute);
  font-size: 0.85rem;
  white-space: nowrap;
  margin-left: 12px;
}

/* ===== Login ===== */
.page-login { display: flex; flex-direction: column; min-height: 100vh; }
.login-main {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
}
.login-card {
  width: 100%;
  max-width: 360px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  box-shadow: var(--shadow);
}
.login-card h1 { margin: 0; font-size: 1.5rem; }
.login-card label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.9rem;
  color: var(--text-dim);
}
.login-card input {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.95rem;
}
.login-card input:focus {
  outline: none;
  border-color: var(--primary);
}

.error {
  color: var(--danger);
  background: rgba(255, 107, 139, 0.08);
  border: 1px solid rgba(255, 107, 139, 0.2);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  margin: 0;
}

/* ===== App layout ===== */
.page-app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}
.app-topbar { padding: 12px 20px; }
.app-topbar-actions { display: flex; gap: 8px; align-items: center; }

.app-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  flex: 1;
  min-height: 0;
  overflow: hidden;
}

.sidebar {
  background: var(--bg-elev);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 18px 14px 32px;
}
.sidebar-header { padding: 0 6px 14px; border-bottom: 1px solid var(--border); margin-bottom: 14px; }
.sidebar-header h2 { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.10em; color: var(--text-dim); margin: 0 0 8px; }

.progress-bar {
  height: 4px;
  background: var(--bg);
  border-radius: 999px;
  overflow: hidden;
  margin-top: 4px;
}
.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, #71717a, #f4f4f5);
  transition: width 0.3s;
  width: 0;
}

.lessons-nav .module-group {
  margin-bottom: 6px;
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.lessons-nav .module-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  border: none;
  color: var(--text-dim);
  padding: 9px 10px;
  font-family: inherit;
  font-size: 0.85rem;
  text-align: left;
  cursor: pointer;
  border-radius: var(--radius-sm);
}
.lessons-nav .module-toggle:hover { background: var(--bg-elev-2); color: var(--text); }
.lessons-nav .module-toggle.open { color: var(--text); }
.lessons-nav .module-toggle-name { flex: 1; font-weight: 500; }
.lessons-nav .module-toggle-meta { font-size: 0.72rem; color: var(--text-mute); }
.lessons-nav .module-toggle-arrow {
  display: inline-block;
  transition: transform 0.2s;
  color: var(--text-mute);
}
.lessons-nav .module-toggle.open .module-toggle-arrow { transform: rotate(180deg); }

.lessons-nav .module-lessons { padding: 4px 0 8px 4px; display: none; }
.lessons-nav .module-toggle.open + .module-lessons { display: block; }

.lessons-nav .lesson-link {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 7px 10px;
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 0.9rem;
  cursor: pointer;
  border: 1px solid transparent;
  margin-left: 4px;
}
.lessons-nav .lesson-link:hover { background: var(--bg-elev-2); text-decoration: none; }
.lessons-nav .lesson-link.active {
  background: var(--bg-elev-2);
  border-color: var(--border-strong);
}
.lessons-nav .lesson-link .lesson-link-title { flex: 1; }
.lessons-nav .lesson-link .lesson-duration { color: var(--text-mute); font-size: 0.74rem; }
.lessons-nav .lesson-link .check {
  width: 14px;
  height: 14px;
  border: 1.5px solid var(--border-strong);
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 10px;
  color: transparent;
}
.lessons-nav .lesson-link.completed .check {
  background: var(--success);
  border-color: var(--success);
  color: var(--bg);
}
.lessons-nav .lesson-link.completed .check::after { content: '✓'; }

.content {
  overflow-y: auto;
  padding: 32px 40px;
}
.content-inner {
  max-width: 760px;
  margin: 0 auto;
}

.lesson-header {
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.lesson-header h1 { margin: 0 0 6px; font-size: 1.8rem; }
.lesson-meta { display: flex; gap: 14px; color: var(--text-dim); font-size: 0.9rem; }

.lesson-body { font-size: 1rem; }
.lesson-body h1, .lesson-body h2, .lesson-body h3 { letter-spacing: -0.01em; }
.lesson-body h1 { font-size: 1.6rem; margin: 32px 0 14px; }
.lesson-body h2 { font-size: 1.25rem; margin: 28px 0 10px; }
.lesson-body h3 { font-size: 1.05rem; margin: 22px 0 8px; }
.lesson-body p { margin: 0 0 14px; }
.lesson-body ul, .lesson-body ol { margin: 0 0 14px; padding-left: 22px; }
.lesson-body li { margin: 4px 0; }
.lesson-body blockquote {
  margin: 14px 0;
  padding: 10px 16px;
  background: var(--bg-elev);
  border-left: 3px solid var(--border-strong);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-dim);
}
.lesson-body code {
  font-family: var(--font-mono);
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 0.88em;
}
.lesson-body pre {
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  overflow-x: auto;
  margin: 14px 0;
}
.lesson-body pre code {
  background: transparent;
  border: none;
  padding: 0;
  font-size: 0.88rem;
}
.lesson-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0;
  font-size: 0.92rem;
}
.lesson-body th, .lesson-body td {
  border: 1px solid var(--border);
  padding: 8px 12px;
  text-align: left;
}
.lesson-body th { background: var(--bg-elev); }

.lesson-nav-buttons {
  display: flex;
  justify-content: space-between;
  margin-top: 36px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
  gap: 12px;
}

/* ===== Welcome screen ===== */
.welcome {
  text-align: center;
  padding: 40px 20px 20px;
  max-width: 640px;
  margin: 0 auto;
}
.welcome-eyebrow {
  display: inline-block;
  color: var(--primary);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.10em;
  margin-bottom: 14px;
}
.welcome h1 {
  font-size: 2.2rem;
  margin: 0 0 14px;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #ffffff 0%, #a1a1aa 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.welcome .lead {
  color: var(--text-dim);
  font-size: 1.05rem;
  margin: 0 0 28px;
}
.welcome-stats {
  display: flex;
  justify-content: center;
  gap: 28px;
  flex-wrap: wrap;
  margin: 32px 0 0;
  padding-top: 28px;
  border-top: 1px solid var(--border);
}
.welcome-stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}
.welcome-stat-value { font-size: 1.6rem; font-weight: 600; color: var(--text); }
.welcome-stat-label { font-size: 0.8rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.06em; }

/* ===== Floating tutor bubble ===== */
.tutor-fab {
  position: fixed;
  right: 24px;
  bottom: 24px;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 18px 12px 14px;
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  color: var(--text);
  font-family: inherit;
  font-size: 0.92rem;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
  z-index: 60;
  transition: transform 0.15s, border-color 0.15s, background 0.15s;
}
.tutor-fab:hover {
  border-color: var(--primary);
  background: var(--bg-elev-2);
  transform: translateY(-2px);
}
.tutor-fab-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--primary);
  color: var(--primary-fg);
  font-weight: 700;
  font-size: 0.95rem;
}
.tutor-fab.hidden { display: none; }

.tutor-popup {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 380px;
  max-width: calc(100vw - 32px);
  height: 540px;
  max-height: calc(100vh - 100px);
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.55);
  display: none;
  flex-direction: column;
  z-index: 60;
  overflow: hidden;
}
.tutor-popup.open { display: flex; }
.tutor-popup-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  gap: 12px;
}
.tutor-popup-actions { display: flex; gap: 6px; flex-shrink: 0; }

.chat-messages {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 14px 16px;
}
.msg {
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.92rem;
  line-height: 1.5;
  word-wrap: break-word;
}
.msg.user {
  background: var(--bg-elev-2);
  border: 1px solid var(--border-strong);
  align-self: flex-end;
  max-width: 90%;
}
.msg.assistant {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  max-width: 95%;
}
.msg.assistant pre {
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  padding: 8px 10px;
  border-radius: 4px;
  font-size: 0.82rem;
  overflow-x: auto;
}
.msg.assistant code {
  font-family: var(--font-mono);
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  padding: 1px 5px;
  border-radius: 3px;
  font-size: 0.85em;
}
.msg.assistant pre code { background: transparent; border: none; padding: 0; }
.msg.system { color: var(--text-mute); font-size: 0.85rem; text-align: center; }

.chat-input {
  display: flex;
  gap: 8px;
  align-items: stretch;
  padding: 12px 14px 14px;
  border-top: 1px solid var(--border);
}
.chat-input input {
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 9px 12px;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.92rem;
}
.chat-input input:focus { outline: none; border-color: var(--primary); }
.chat-input button { white-space: nowrap; padding: 8px 14px; font-size: 0.88rem; }

.typing-dots {
  display: inline-block;
}
.typing-dots span {
  display: inline-block;
  width: 6px;
  height: 6px;
  margin: 0 2px;
  background: var(--text-dim);
  border-radius: 50%;
  animation: dot 1.2s infinite ease-in-out;
}
.typing-dots span:nth-child(2) { animation-delay: 0.2s; }
.typing-dots span:nth-child(3) { animation-delay: 0.4s; }
@keyframes dot {
  0%, 80%, 100% { opacity: 0.3; transform: translateY(0); }
  40% { opacity: 1; transform: translateY(-3px); }
}

/* Live-typing blinking cursor */
.cursor-blink {
  display: inline-block;
  width: 7px;
  height: 1em;
  margin-left: 2px;
  background: var(--text);
  vertical-align: text-bottom;
  animation: cursor 1s steps(2, start) infinite;
}
@keyframes cursor {
  to { background: transparent; }
}
.msg.streaming p:last-child,
.msg.streaming li:last-child {
  display: inline;
}

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--border);
  padding: 18px 28px;
  color: var(--text-dim);
  font-size: 0.9rem;
  text-align: center;
}

/* ===== Responsive ===== */
@media (max-width: 980px) {
  .app-layout {
    grid-template-columns: 240px 1fr;
  }
}

@media (max-width: 720px) {
  .mobile-only { display: inline-flex; }
  .app-layout {
    grid-template-columns: 1fr;
  }
  .sidebar {
    position: fixed;
    top: 56px; bottom: 0; left: 0;
    width: 260px;
    z-index: 40;
    background: var(--bg-elev);
    transform: translateX(-100%);
    transition: transform 0.2s;
  }
  .sidebar.open { transform: translateX(0); box-shadow: var(--shadow); }
  .content { padding: 20px 18px; }

  .tutor-fab-label { display: none; }
  .tutor-fab { padding: 12px; }
  .tutor-popup {
    right: 12px;
    bottom: 12px;
    width: calc(100vw - 24px);
  }
}