:root {
    --bg-deep: #020203;
    --bg-base: #07070b;
    --bg-elevated: #0e0e14;
    --surface: rgba(255,255,255,0.045);
    --surface-2: rgba(255,255,255,0.07);
    --border: rgba(255,255,255,0.08);
    --border-strong: rgba(255,255,255,0.14);
    --fg: #EDEDEF;
    --fg-muted: #8A8F98;
    --fg-dim: #5C616B;
    --accent: #7C3AED;
    --accent-2: #22D3EE;
    --accent-3: #A78BFA;
    --success: #10B981;
    --danger: #EF4444;
    --glow: rgba(124,58,237,0.35);
    --radius: 16px;
    --ease: cubic-bezier(0.16, 1, 0.3, 1);
    --phone-w: 390px;
    --phone-h: 844px;
  }
  * { box-sizing: border-box; margin: 0; padding: 0; }
  html { scroll-behavior: smooth; }
  body {
    font-family: Inter, system-ui, sans-serif;
    background: var(--bg-deep);
    color: var(--fg);
    min-height: 100vh;
    line-height: 1.5;
  }
  .logo {
    width: 36px; height: 36px; border-radius: 10px;
    background: linear-gradient(135deg, #7C3AED, #22D3EE);
    display: grid; place-items: center;
    box-shadow: 0 0 24px var(--glow);
    font-weight: 800; font-size: 14px; color: #fff;
  }




  .status-bar { display: none !important; }

  .blob {
    position: absolute; border-radius: 50%; filter: blur(40px); pointer-events: none; z-index: 0;
  }
  .blob-1 { width: 180px; height: 180px; background: rgba(124,58,237,0.35); top: -40px; right: -30px; }
  .blob-2 { width: 160px; height: 160px; background: rgba(34,211,238,0.2); bottom: 120px; left: -50px; }
  .blob-3 { width: 120px; height: 120px; background: rgba(167,139,250,0.15); top: 40%; right: -20px; }

  .content {
    flex: 1; padding: 20px 20px 28px;
    position: relative; z-index: 2;
    overflow-y: auto;
    display: flex; flex-direction: column;
  }
  .content::-webkit-scrollbar { width: 0; }

  .bobo-logo-row {
    display: flex; align-items: center; gap: 10px; margin-bottom: 28px;
  }
  .bobo-logo-row .mark {
    width: 40px; height: 40px; border-radius: 12px;
    background: linear-gradient(135deg, #7C3AED 0%, #22D3EE 100%);
    display: grid; place-items: center; font-weight: 800; font-size: 13px;
    box-shadow: 0 8px 28px var(--glow);
  }
  .bobo-logo-row .name { font-weight: 700; font-size: 18px; letter-spacing: -0.02em; }
  .bobo-logo-row .sub { font-size: 11px; color: var(--fg-muted); }

  .eyebrow {
    font-size: 12px; font-weight: 600; letter-spacing: 0.04em;
    color: var(--accent-2); margin-bottom: 10px;
  }
  .title {
    font-size: 28px; font-weight: 800; letter-spacing: -0.03em;
    line-height: 1.15; margin-bottom: 10px;
  }
  .subtitle { font-size: 14px; color: var(--fg-muted); margin-bottom: 24px; line-height: 1.55; }

  .field { margin-bottom: 14px; }
  .field label {
    display: block; font-size: 12px; font-weight: 500;
    color: var(--fg-muted); margin-bottom: 8px;
  }
  .field label .req { color: var(--danger); margin-left: 2px; }
  .input {
    width: 100%; height: 52px; border-radius: 14px;
    background: var(--surface); border: 1px solid var(--border);
    color: var(--fg); padding: 0 16px;
    font-size: 15px; font-family: inherit;
    outline: none;
    display: flex; align-items: center; gap: 10px;
  }
  .input.focus {
    border-color: rgba(124,58,237,0.55);
    box-shadow: 0 0 0 3px rgba(124,58,237,0.18);
  }
  .input input {
    flex: 1; background: transparent; border: 0; outline: 0;
    color: var(--fg); font-size: 15px; font-family: inherit; width: 100%;
  }
  .input input::placeholder { color: var(--fg-dim); }
  .input .prefix {
    font-size: 13px; color: var(--fg-muted); padding-right: 8px;
    border-right: 1px solid var(--border);
  }
  .input .action {
    font-size: 13px; font-weight: 600; color: var(--accent-2);
    white-space: nowrap;
  }

  .checkbox-row {
    display: flex; align-items: flex-start; gap: 10px;
    margin: 8px 0 20px; font-size: 12.5px; color: var(--fg-muted);
  }
  .checkbox {
    width: 18px; height: 18px; border-radius: 6px; flex-shrink: 0;
    border: 1.5px solid var(--border-strong); margin-top: 1px;
    background: linear-gradient(135deg, #7C3AED, #6366F1);
    display: grid; place-items: center;
  }
  .checkbox svg { width: 11px; height: 11px; stroke: #fff; fill: none; stroke-width: 2.5; }
  .checkbox-row a { color: var(--accent-3); text-decoration: none; }

  .btn {
    width: 100%; height: 54px; border-radius: 16px; border: 0;
    font-size: 16px; font-weight: 600; font-family: inherit;
    display: grid; place-items: center;
  }
  .btn-primary {
    color: #fff;
    background: linear-gradient(135deg, #7C3AED 0%, #6366F1 50%, #4F46E5 100%);
    box-shadow: 0 8px 32px var(--glow), inset 0 1px 0 rgba(255,255,255,0.2);
  }
  .btn-ghost {
    background: var(--surface); color: var(--fg);
    border: 1px solid var(--border); margin-top: 10px;
  }
  .btn-row { margin-top: auto; padding-top: 16px; }

  .tabs {
    display: grid; grid-template-columns: 1fr 1fr; gap: 6px;
    padding: 4px; border-radius: 14px; background: var(--surface);
    border: 1px solid var(--border); margin-bottom: 22px;
  }
  .tab {
    height: 40px; border-radius: 10px; display: grid; place-items: center;
    font-size: 13.5px; font-weight: 500; color: var(--fg-muted);
  }
  .tab.on {
    background: rgba(124,58,237,0.25);
    color: var(--fg); border: 1px solid rgba(124,58,237,0.35);
  }

  .hint { font-size: 12px; color: var(--fg-dim); margin-top: 8px; }
  .strength { display: flex; gap: 4px; margin-top: 10px; }
  .strength i {
    flex: 1; height: 4px; border-radius: 2px; background: var(--surface-2);
  }
  .strength i.on { background: var(--success); }
  .strength i.mid { background: #F59E0B; }

  .card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
  }
  .card-glow {
    background: linear-gradient(160deg, rgba(124,58,237,0.18), rgba(34,211,238,0.06));
    border: 1px solid rgba(124,58,237,0.25);
  }

  .splash-center {
    flex: 1; display: flex; flex-direction: column;
    align-items: center; justify-content: center; text-align: center;
  }
  .splash-orb {
    width: 96px; height: 96px; border-radius: 28px;
    background: linear-gradient(135deg, #7C3AED, #22D3EE);
    display: grid; place-items: center;
    box-shadow: 0 0 60px var(--glow), 0 20px 40px rgba(0,0,0,0.4);
    margin-bottom: 24px; position: relative;
  }
  .splash-orb::after {
    content: ""; position: absolute; inset: -8px; border-radius: 34px;
    border: 1px solid rgba(124,58,237,0.35);
    animation: pulse 2.4s var(--ease) infinite;
  }
  @keyframes pulse {
    0%, 100% { opacity: .6; transform: scale(1); }
    50% { opacity: 0; transform: scale(1.08); }
  }
  .splash-center h2 { font-size: 32px; font-weight: 800; letter-spacing: -0.03em; }
  .splash-center p { color: var(--fg-muted); margin-top: 8px; font-size: 14px; }
  .splash-footer {
    text-align: center; font-size: 12px; color: var(--fg-dim);
    padding-bottom: 8px;
  }

  .home-header {
    display: flex; justify-content: space-between; align-items: center;
    margin-bottom: 18px;
  }
  .avatar {
    width: 40px; height: 40px; border-radius: 14px;
    background: linear-gradient(135deg, #6366F1, #22D3EE);
    display: grid; place-items: center; font-weight: 700; font-size: 13px;
  }
  .greet { font-size: 13px; color: var(--fg-muted); }
  .greet b { color: var(--fg); font-size: 16px; display: block; margin-top: 2px; }
  .icon-btn {
    width: 40px; height: 40px; border-radius: 12px;
    background: var(--surface); border: 1px solid var(--border);
    display: grid; place-items: center; color: var(--fg-muted);
  }

  .hero-card { padding: 20px; margin-bottom: 16px; position: relative; overflow: hidden; }
  .hero-card .label { font-size: 12px; color: var(--fg-muted); }
  .hero-card .headline {
    font-size: 22px; font-weight: 800; letter-spacing: -0.03em; margin: 8px 0 12px; line-height: 1.25;
  }
  .chip-row { display: flex; gap: 8px; flex-wrap: wrap; }
  .chip {
    padding: 6px 10px; border-radius: 999px; font-size: 11px; font-weight: 500;
    background: rgba(255,255,255,0.08); color: var(--fg);
  }
  .chip.accent { color: var(--accent-2); background: rgba(34,211,238,0.12); }

  .section-h {
    display: flex; justify-content: space-between; align-items: center;
    margin: 18px 0 10px; font-size: 14px; font-weight: 600;
  }
  .section-h a { font-size: 12px; color: var(--accent-2); text-decoration: none; font-weight: 500; }
  .grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
  .mini-card {
    padding: 14px; border-radius: 14px;
    background: var(--surface); border: 1px solid var(--border);
  }
  .mini-card .ic {
    width: 32px; height: 32px; border-radius: 10px; margin-bottom: 10px;
    display: grid; place-items: center; font-size: 13px; font-weight: 700;
    background: rgba(124,58,237,0.2); color: var(--accent-3);
  }
  .mini-card h4 { font-size: 13px; font-weight: 600; margin-bottom: 4px; }
  .mini-card p { font-size: 11px; color: var(--fg-muted); line-height: 1.4; }

  .list-item {
    display: flex; gap: 12px; align-items: center;
    padding: 12px 0; border-bottom: 1px solid var(--border);
  }
  .list-item:last-child { border-bottom: 0; }
  .list-item .dot {
    width: 36px; height: 36px; border-radius: 12px;
    background: var(--surface-2); display: grid; place-items: center;
    font-size: 12px; color: var(--accent-2); font-weight: 600;
  }
  .list-item .meta { flex: 1; min-width: 0; }
  .list-item .meta b { font-size: 13px; font-weight: 600; display: block; }
  .list-item .meta span { font-size: 11px; color: var(--fg-muted); }
  .list-item .val { font-size: 12px; font-weight: 600; text-align: right; color: var(--fg-muted); }
  .list-item .val.ok { color: var(--success); }

  .tabbar {
    display: grid; grid-template-columns: repeat(4, 1fr);
    border-top: 1px solid var(--border);
    background: rgba(8,8,12,0.92);
    backdrop-filter: blur(16px);
    padding: 8px 6px 18px;
    margin-top: auto;
  }
  .tabbar div {
    text-align: center; font-size: 10px; color: var(--fg-dim);
    display: flex; flex-direction: column; align-items: center; gap: 4px;
  }
  .tabbar div.on { color: var(--accent-3); }
  .tabbar .ico {
    width: 22px; height: 22px; border-radius: 6px;
    display: grid; place-items: center;
  }
  .tabbar div.on .ico { background: rgba(124,58,237,0.2); }

  .modal-layer {
    position: absolute; inset: 0; z-index: 30;
    background: rgba(0,0,0,0.55);
    display: flex; align-items: flex-end;
    border-radius: 34px;
  }
  .sheet {
    width: 100%; background: #12121a;
    border-radius: 24px 24px 34px 34px;
    border: 1px solid var(--border);
    padding: 12px 20px 32px;
    box-shadow: 0 -20px 60px rgba(0,0,0,0.5);
  }
  .sheet .handle {
    width: 40px; height: 4px; border-radius: 2px;
    background: var(--border-strong); margin: 4px auto 16px;
  }
  .sheet h3 { font-size: 18px; font-weight: 700; margin-bottom: 6px; }
  .sheet p { font-size: 13px; color: var(--fg-muted); margin-bottom: 18px; line-height: 1.55; }

  .loading-center {
    flex: 1; display: flex; flex-direction: column;
    align-items: center; justify-content: center; gap: 16px;
  }
  .spinner {
    width: 44px; height: 44px; border-radius: 50%;
    border: 3px solid rgba(124,58,237,0.2);
    border-top-color: var(--accent);
    animation: spin 0.8s linear infinite;
  }
  @keyframes spin { to { transform: rotate(360deg); } }

  .toast {
    position: absolute; top: 64px; left: 20px; right: 20px; z-index: 40;
    padding: 12px 14px; border-radius: 14px;
    background: rgba(245,158,11,0.12);
    border: 1px solid rgba(245,158,11,0.35);
    color: #FCD34D; font-size: 12.5px; font-weight: 500;
    display: flex; align-items: center; gap: 10px;
  }

  .verify-badge {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 4px 10px; border-radius: 999px; font-size: 11px;
    background: rgba(239,68,68,0.12); color: #FCA5A5;
    border: 1px solid rgba(239,68,68,0.25);
  }
  .verify-badge.ok {
    background: rgba(16,185,129,0.12); color: #6EE7B7;
    border-color: rgba(16,185,129,0.25);
  }

  .progress-dots {
    display: flex; gap: 6px; justify-content: center; margin: 12px 0 20px;
  }
  .progress-dots i {
    width: 6px; height: 6px; border-radius: 50%; background: var(--surface-2);
  }
  .progress-dots i.on { background: var(--accent); width: 18px; border-radius: 4px; }

  .id-preview {
    border: 1px dashed var(--border-strong);
    border-radius: 14px; padding: 20px; text-align: center;
    color: var(--fg-muted); font-size: 12px; margin-bottom: 14px;
    background: var(--surface);
  }
  .id-preview .cam {
    width: 48px; height: 48px; border-radius: 14px; margin: 0 auto 10px;
    background: rgba(124,58,237,0.15); display: grid; place-items: center;
    color: var(--accent-3); font-size: 18px;
  }

  .safe-note {
    font-size: 12px; color: var(--fg-dim); text-align: center; margin-top: 12px;
    line-height: 1.45;
  }

  .topic-cover {
    height: 140px; border-radius: 16px; margin-bottom: 14px;
    background:
      linear-gradient(135deg, rgba(124,58,237,0.45), rgba(34,211,238,0.2)),
      radial-gradient(circle at 70% 30%, rgba(255,255,255,0.15), transparent 50%);
    border: 1px solid var(--border);
    display: flex; align-items: flex-end; padding: 14px;
  }
  .topic-cover span {
    font-size: 13px; font-weight: 600;
    background: rgba(0,0,0,0.35); padding: 6px 10px; border-radius: 8px;
  }

  @media (max-width: 900px) {
  }

html, body {
  margin: 0; height: 100%; overflow: hidden;
  background: #020203;
  font-family: Inter, system-ui, sans-serif;
  color: var(--fg, #EDEDEF);
  -webkit-font-smoothing: antialiased;
}
#app {
  height: 100%;
  max-width: 430px;
  margin: 0 auto;
  position: relative;
  display: flex;
  flex-direction: column;
  background: linear-gradient(180deg, #0c0c14 0%, #06060a 100%);
  overflow: hidden;
  box-shadow: 0 0 0 1px rgba(255,255,255,0.06), 0 0 80px rgba(0,0,0,.5);
}
@media (min-width: 480px) {
  body {
    display: flex; align-items: center; justify-content: center;
    background:
      radial-gradient(900px 400px at 20% -10%, rgba(124,58,237,0.12), transparent 60%),
      radial-gradient(700px 360px at 90% 10%, rgba(34,211,238,0.08), transparent 55%),
      #020203;
  }
  #app { height: min(100vh, 900px); border-radius: 28px; }
}
.screen {
  display: none;
  flex: 1;
  flex-direction: column;
  min-height: 0;
  position: relative;
  overflow: hidden;
}
.screen.on { display: flex; }
.screen > .content {
  flex: 1;
  min-height: 0;
  padding: 20px 20px 28px;
  position: relative;
  z-index: 2;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  -webkit-overflow-scrolling: touch;
}
.screen > .content::-webkit-scrollbar { width: 0; height: 0; }
.status-bar { display: none !important; }
.blob {
  position: absolute; border-radius: 50%; filter: blur(40px);
  pointer-events: none; z-index: 0;
}
.blob-1 { width: 180px; height: 180px; background: rgba(124,58,237,0.35); top: -40px; right: -30px; }
.blob-2 { width: 160px; height: 160px; background: rgba(34,211,238,0.2); bottom: 120px; left: -50px; }
.blob-3 { width: 120px; height: 120px; background: rgba(167,139,250,0.15); top: 40%; right: -20px; }
.input input {
  flex: 1; background: transparent; border: 0; outline: 0;
  color: var(--fg); font-size: 15px; font-family: inherit; width: 100%; min-width: 0;
}
.input input::placeholder { color: var(--fg-dim); }
.btn { cursor: pointer; user-select: none; }
.btn:disabled { opacity: .45; pointer-events: none; }
.tab, .action, .icon-btn, .tabbar > div, .checkbox-row { cursor: pointer; }
.checkbox.off {
  background: transparent !important;
  border: 1.5px solid var(--border-strong);
}
.checkbox.off svg { display: none; }
.err {
  color: var(--danger); font-size: 13px; margin-bottom: 10px; min-height: 0;
}
.toast-host {
  position: absolute; top: 58px; left: 20px; right: 20px; z-index: 40;
}
.home-body { flex: 1; min-height: 0; overflow-y: auto; padding: 8px 20px 12px; position: relative; z-index: 2; }
.home-body::-webkit-scrollbar { width: 0; }
.tabbar {
  flex-shrink: 0;
  margin-top: 0 !important;
}
.modal-layer {
  position: absolute; inset: 0; z-index: 30;
  background: rgba(0,0,0,0.55);
  display: none; align-items: flex-end;
  border-radius: 0 !important;
}
.modal-layer.show { display: flex; }
.sheet { border-radius: 24px 24px 0 0 !important; width: 100%; }
.back-row { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.icon-btn {
  width: 40px; height: 40px; border-radius: 12px;
  background: var(--surface); border: 1px solid var(--border);
  display: grid; place-items: center; color: var(--fg-muted); flex-shrink: 0;
}
.forgot { text-align: right; margin-bottom: 16px; }
.forgot a { font-size: 12px; color: var(--accent-2); text-decoration: none; }
.legal p { margin-bottom: 12px; font-size: 13px; color: var(--fg-muted); line-height: 1.7; }
.legal b { color: var(--fg); }
.success-mark {
  width: 72px; height: 72px; border-radius: 50%; margin: 0 auto 20px;
  background: rgba(16,185,129,0.15); border: 1px solid rgba(16,185,129,0.35);
  display: grid; place-items: center; color: var(--success); font-size: 32px;
}
.progress-line {
  height: 6px; border-radius: 3px; background: var(--surface-2); overflow: hidden;
}
.progress-line > span {
  display: block; height: 100%; width: 0%;
  background: linear-gradient(90deg,#7C3AED,#22D3EE);
}
.hidden { display: none !important; }
.btn.danger { color: var(--danger) !important; }

/* —— extra interactive screens —— */
.chat-log {
  flex: 1;
  min-height: 180px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 4px 0 8px;
  -webkit-overflow-scrolling: touch;
}
.chat-log::-webkit-scrollbar { width: 0; }
.bubble {
  max-width: 88%;
  padding: 12px 14px;
  border-radius: 16px;
  font-size: 13.5px;
  line-height: 1.55;
  white-space: pre-wrap;
}
.bubble.bot {
  align-self: flex-start;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--fg);
  border-bottom-left-radius: 6px;
}
.bubble.me {
  align-self: flex-end;
  background: linear-gradient(135deg, rgba(124,58,237,0.45), rgba(99,102,241,0.35));
  border: 1px solid rgba(124,58,237,0.35);
  color: #fff;
  border-bottom-right-radius: 6px;
}
.chat-input-row {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-top: auto;
  padding-top: 8px;
}
.chat-send {
  width: auto !important;
  min-width: 72px;
  height: 48px !important;
  padding: 0 16px;
  border-radius: 14px !important;
  flex-shrink: 0;
}
.chip.pick {
  cursor: pointer;
  border: 1px solid var(--border);
  user-select: none;
}
.chip.pick.on {
  color: var(--accent-2);
  background: rgba(34,211,238,0.14);
  border-color: rgba(34,211,238,0.35);
}
.quiz-opt {
  display: block;
  width: 100%;
  text-align: left;
  padding: 14px 16px;
  margin-bottom: 10px;
  border-radius: 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--fg);
  font-size: 14px;
  font-family: inherit;
  cursor: pointer;
}
.quiz-opt:hover { border-color: var(--border-strong); }
.quiz-opt.correct {
  border-color: rgba(16,185,129,0.45);
  background: rgba(16,185,129,0.12);
}
.quiz-opt.wrong {
  border-color: rgba(239,68,68,0.45);
  background: rgba(239,68,68,0.1);
}
.article-body p {
  font-size: 14px;
  color: var(--fg-muted);
  line-height: 1.75;
  margin-bottom: 14px;
}
.article-body h3 {
  font-size: 16px;
  font-weight: 700;
  margin: 18px 0 10px;
}
.lesson-row {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
}
.lesson-row:last-child { border-bottom: 0; }
.switch-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.switch-row:last-child { border-bottom: 0; }
.switch {
  width: 44px; height: 26px; border-radius: 999px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  position: relative;
  cursor: pointer;
  flex-shrink: 0;
  transition: background .2s var(--ease);
}
.switch.on {
  background: linear-gradient(135deg, #7C3AED, #6366F1);
  border-color: transparent;
}
.switch i {
  position: absolute; top: 2px; left: 2px;
  width: 20px; height: 20px; border-radius: 50%;
  background: #fff;
  transition: transform .2s var(--ease);
}
.switch.on i { transform: translateX(18px); }
.demo-banner {
  position: absolute; top: 52px; left: 16px; right: 16px; z-index: 50;
  padding: 8px 12px; border-radius: 10px;
  background: rgba(34,211,238,0.1);
  border: 1px solid rgba(34,211,238,0.28);
  color: var(--accent-2); font-size: 11px; font-weight: 500;
  text-align: center; pointer-events: none;
  display: none;
}
.demo-banner.show { display: block; }
.clickable { cursor: pointer; }
.list-item.clickable:active, .mini-card.clickable:active { opacity: .85; }
.locked-tag {
  font-size: 11px; color: #FCD34D;
  background: rgba(245,158,11,0.12);
  border: 1px solid rgba(245,158,11,0.3);
  padding: 2px 8px; border-radius: 999px;
}