:root {
  --green: #58cc02;
  --green-dark: #46a302;
  --green-soft: #eefbe5;
  --gold: #ffb800;
  --gold-dark: #d99b00;
  --gold-soft: #fff8db;
  --sky: #1cb0f6;
  --sky-dark: #0b8fd0;
  --sky-soft: #e6f6fe;
  --red: #ff4b4b;
  --red-soft: #ffeaea;
  --violet: #9b51e0;
  --violet-soft: #f4ebfd;
  --flame: #ff9600;
  --bg: #f6f9fc;
  --surface: #ffffff;
  --border: #e2e8f0;
  --text: #1e293b;
  --muted: #64748b;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  padding-bottom: 88px;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  background: var(--surface);
  border-bottom: 2px solid var(--border);
  padding: 10px 18px;
}

.topbar-inner {
  max-width: 980px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.25rem;
}

.cefr-pill {
  background: var(--sky-soft);
  color: var(--sky-dark);
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 800;
}

.hud-stats {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.hud-chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 6px 12px;
  border-radius: 999px;
  font-weight: 800;
  font-size: 0.92rem;
  background: #f8fafc;
  border: 1.5px solid var(--border);
  cursor: pointer;
}

.hud-chip.streak { color: var(--flame); }
.hud-chip.stars { color: #b45309; background: var(--gold-soft); border-color: #fde68a; }
.hud-chip.hearts { color: var(--red); }

.apk-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 13px;
  border-radius: 12px;
  background: var(--sky-soft);
  color: var(--sky-dark);
  border: 1.5px solid #bae6fd;
  font-weight: 700;
  font-size: 0.84rem;
  text-decoration: none;
}

.container {
  max-width: 920px;
  margin: 20px auto;
  padding: 0 16px;
}

.banner-safe {
  background: linear-gradient(90deg, var(--gold-soft), #f0fdf4);
  border: 2px solid #fde68a;
  border-radius: 20px;
  padding: 14px 18px;
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.banner-safe p {
  font-size: 0.88rem;
  color: var(--muted);
  margin-top: 2px;
}

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

.card {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: 22px;
  padding: 20px;
  margin-bottom: 16px;
}

.unit-header {
  border-radius: 20px;
  padding: 18px 20px;
  color: #fff;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.skill-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  margin-bottom: 22px;
}

.skill-node {
  background: var(--surface);
  border: 2px solid var(--border);
  border-bottom-width: 5px;
  border-radius: 20px;
  padding: 16px;
  cursor: pointer;
  transition: transform 0.1s ease, border-color 0.15s ease;
  text-align: left;
}

.skill-node:hover {
  border-color: var(--green);
  transform: translateY(-2px);
}

.skill-node h4 {
  font-size: 1.05rem;
  margin: 6px 0 4px;
}

.skill-node p {
  font-size: 0.84rem;
  color: var(--muted);
}

.crowns {
  font-size: 0.82rem;
  font-weight: 800;
  color: #b45309;
  margin-top: 8px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: none;
  border-radius: 14px;
  padding: 12px 18px;
  font-size: 0.96rem;
  font-weight: 800;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.08s ease, opacity 0.15s;
}

.btn:active { transform: scale(0.98); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-green {
  background: var(--green);
  color: #fff;
  box-shadow: 0 4px 0 var(--green-dark);
}

.btn-gold {
  background: var(--gold);
  color: #1e293b;
  box-shadow: 0 4px 0 var(--gold-dark);
}

.btn-violet {
  background: var(--violet);
  color: #fff;
  box-shadow: 0 4px 0 #7a35b8;
}

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

.input, select {
  width: 100%;
  padding: 12px 14px;
  border: 2px solid var(--border);
  border-radius: 14px;
  font-size: 0.96rem;
  outline: none;
}

.input:focus, select:focus {
  border-color: var(--sky);
}

.row {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--surface);
  border-top: 2px solid var(--border);
  z-index: 30;
}

.bottom-nav-inner {
  max-width: 720px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
}

.nav-btn {
  background: none;
  border: none;
  padding: 10px 4px;
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--muted);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
}

.nav-btn.active {
  color: var(--green-dark);
}

.nav-btn span.icon {
  font-size: 1.25rem;
}

/* Modal Lesson & Story Overlay */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.55);
  z-index: 60;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 16px;
}

.overlay.open {
  display: flex;
}

.modal {
  background: var(--surface);
  max-width: 640px;
  width: 100%;
  max-height: 92vh;
  overflow-y: auto;
  border-radius: 26px;
  padding: 24px;
  border: 2px solid var(--border);
}

.progress-track {
  flex: 1;
  height: 12px;
  background: #e2e8f0;
  border-radius: 999px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--green);
  transition: width 0.25s ease;
}

.option-btn {
  width: 100%;
  text-align: left;
  padding: 14px 16px;
  border-radius: 16px;
  border: 2px solid var(--border);
  border-bottom-width: 4px;
  background: var(--surface);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 10px;
  cursor: pointer;
}

.option-btn.selected {
  border-color: var(--sky);
  background: var(--sky-soft);
  color: var(--sky-dark);
}

.word-chip {
  padding: 9px 14px;
  border-radius: 12px;
  border: 2px solid var(--border);
  border-bottom-width: 4px;
  background: var(--surface);
  font-weight: 700;
  cursor: pointer;
}

.feedback-box {
  margin-top: 14px;
  padding: 14px 16px;
  border-radius: 16px;
  font-weight: 700;
}

.feedback-box.correct {
  background: var(--green-soft);
  color: #166534;
  border: 2px solid var(--green);
}

.feedback-box.wrong {
  background: var(--red-soft);
  color: #991b1b;
  border: 2px solid var(--red);
}

.week-strip {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 8px;
  margin-top: 12px;
}

.day-pill {
  text-align: center;
  padding: 10px 4px;
  border-radius: 14px;
  border: 1.5px solid var(--border);
  font-size: 0.8rem;
  font-weight: 800;
}

.day-pill.done {
  background: #fff7ed;
  border-color: var(--flame);
  color: #c2410c;
}

.chat-box {
  max-height: 290px;
  overflow-y: auto;
  border: 1.5px solid var(--border);
  border-radius: 16px;
  padding: 12px;
  background: #f8fafc;
  margin: 12px 0;
}

.bubble {
  padding: 10px 14px;
  border-radius: 16px;
  margin-bottom: 10px;
  max-width: 85%;
  line-height: 1.4;
}

.bubble.tutor {
  background: var(--surface);
  border: 1.5px solid var(--border);
}

.bubble.user {
  background: var(--sky);
  color: #fff;
  margin-left: auto;
}

.toast {
  position: fixed;
  bottom: 96px;
  left: 50%;
  transform: translateX(-50%);
  background: #0f172a;
  color: #fff;
  padding: 12px 20px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.9rem;
  z-index: 80;
  display: none;
}

.toast.show { display: block; }