/* ===== Reset ===== */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}

:root{
  --primary:#6C63FF;
  --primary-hover:#5A52E0;
  --primary-light:#EDE9FF;
  --bg:#F7F7FB;
  --surface:#FFFFFF;
  --text:#111827;
  --text2:#6B7280;
  --text3:#9CA3AF;
  --border:#E5E7EB;
  --success:#22C55E;
  --warning:#F59E0B;
  --danger:#EF4444;
  --r:14px;
  --r-sm:10px;
  --shadow-sm:0 1px 3px rgba(0,0,0,.06);
  --shadow:0 4px 16px rgba(0,0,0,.06);
  --shadow-lg:0 12px 40px rgba(0,0,0,.1);
  --teacher-color:#6C63FF;
  --teacher-light:#EDE9FF;
  --font:'Inter',system-ui,-apple-system,sans-serif;
}

html,body{height:100%;font-family:var(--font);background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased}
#app{height:100%;display:flex;flex-direction:column}
.hidden{display:none!important}

/* ===== Onboarding ===== */
.onboarding{
  min-height:100%;
  background:linear-gradient(160deg,#1a103d 0%,#2d1b69 40%,#4c2889 100%);
  display:flex;justify-content:center;
  padding:32px 16px 48px;
  overflow-y:auto;
}

.ob-container{
  width:100%;max-width:760px;
  display:flex;flex-direction:column;
}

.ob-header{text-align:center;margin-bottom:28px}

.ob-logo{
  display:inline-flex;align-items:center;gap:10px;
  font-size:1.7rem;font-weight:800;color:#fff;
  letter-spacing:-.02em;
}
.ob-logo-icon{display:flex}
.ob-subtitle{color:rgba(255,255,255,.6);font-size:.95rem;margin-top:6px}

/* Progress */
.ob-progress{
  height:4px;background:rgba(255,255,255,.12);
  border-radius:4px;margin-bottom:8px;overflow:hidden;
}
.ob-progress-bar{
  height:100%;background:#6C63FF;
  border-radius:4px;transition:width .4s ease;
}

.ob-step-labels{
  display:flex;justify-content:space-between;
  margin-bottom:28px;
}
.ob-step-label{
  font-size:.72rem;font-weight:600;text-transform:uppercase;
  letter-spacing:.06em;color:rgba(255,255,255,.25);
  transition:color .3s;
}
.ob-step-label.active{color:rgba(255,255,255,.9)}
.ob-step-label.done{color:rgba(255,255,255,.5)}

/* Steps */
.ob-step{display:none;animation:fadeUp .35s ease}
.ob-step.active{display:block}

@keyframes fadeUp{
  from{opacity:0;transform:translateY(16px)}
  to{opacity:1;transform:translateY(0)}
}

.ob-title{
  font-size:1.5rem;font-weight:700;color:#fff;
  text-align:center;margin-bottom:6px;
}
.ob-desc{
  text-align:center;color:rgba(255,255,255,.55);
  font-size:.9rem;margin-bottom:20px;
}

/* Language Grid */
.lang-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(130px,1fr));
  gap:10px;margin-top:12px;
}

.lang-card{
  background:rgba(255,255,255,.07);
  backdrop-filter:blur(8px);
  border:1.5px solid rgba(255,255,255,.1);
  border-radius:var(--r-sm);
  padding:16px 10px;text-align:center;
  cursor:pointer;transition:all .2s;
  user-select:none;
}
.lang-card:hover{
  background:rgba(255,255,255,.12);
  border-color:rgba(255,255,255,.2);
  transform:translateY(-2px);
}
.lang-card.selected{
  background:rgba(108,99,255,.25);
  border-color:#6C63FF;
  box-shadow:0 0 0 2px rgba(108,99,255,.3);
}
.lang-card .lc-flag{font-size:1.8rem;display:block;margin-bottom:4px}
.lang-card .lc-name{font-size:.88rem;font-weight:600;color:#fff;display:block}
.lang-card .lc-native{font-size:.75rem;color:rgba(255,255,255,.45);display:block;margin-top:1px}

/* Level Cards */
.level-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(300px,1fr));
  gap:14px;margin-top:12px;
}

.level-card{
  background:rgba(255,255,255,.07);
  backdrop-filter:blur(8px);
  border:1.5px solid rgba(255,255,255,.1);
  border-radius:var(--r);
  padding:24px;cursor:pointer;transition:all .2s;
}
.level-card:hover{background:rgba(255,255,255,.12);transform:translateY(-2px)}
.level-card.selected{background:rgba(108,99,255,.25);border-color:#6C63FF}
.level-card h3{color:#fff;font-size:1.15rem;margin-bottom:6px}
.level-card p{color:rgba(255,255,255,.55);font-size:.88rem;line-height:1.5}

/* Teacher Cards */
.teacher-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(300px,1fr));
  gap:14px;margin-top:12px;
}

.teacher-card{
  background:rgba(255,255,255,.07);
  backdrop-filter:blur(8px);
  border:2px solid rgba(255,255,255,.1);
  border-radius:var(--r);
  padding:22px;cursor:pointer;transition:all .2s;
  display:flex;gap:16px;align-items:flex-start;
}
.teacher-card:hover{background:rgba(255,255,255,.12);transform:translateY(-2px)}
.teacher-card.selected{border-color:var(--teacher-color);background:rgba(108,99,255,.15)}

.tc-avatar{
  width:64px;height:64px;min-width:64px;
  border-radius:50%;overflow:hidden;
  background:rgba(255,255,255,.08);
  display:flex;align-items:center;justify-content:center;
}
.tc-avatar img{width:56px;height:56px}

.tc-info{flex:1;min-width:0}
.tc-name{font-size:1.05rem;font-weight:700;color:#fff}
.tc-title{font-size:.78rem;font-weight:600;color:var(--teacher-color);margin-top:1px}
.tc-style{font-size:.82rem;color:rgba(255,255,255,.5);margin-top:4px}
.tc-desc{font-size:.8rem;color:rgba(255,255,255,.4);margin-top:6px;line-height:1.4}

.btn-voice{
  margin-top:8px;display:inline-flex;align-items:center;gap:4px;
  padding:5px 12px;border-radius:16px;
  border:1px solid rgba(255,255,255,.15);
  background:transparent;color:rgba(255,255,255,.6);
  font-size:.75rem;font-family:var(--font);cursor:pointer;
  transition:all .2s;
}
.btn-voice:hover{border-color:var(--teacher-color);color:#fff}

/* Topic Grid */
.topic-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(155px,1fr));
  gap:10px;margin-top:12px;
}
.topic-card{
  background:rgba(255,255,255,.07);
  backdrop-filter:blur(8px);
  border:1.5px solid rgba(255,255,255,.1);
  border-radius:var(--r-sm);
  padding:18px 12px;text-align:center;
  cursor:pointer;transition:all .2s;
}
.topic-card:hover{background:rgba(255,255,255,.12);transform:translateY(-2px)}
.topic-card.selected{background:rgba(108,99,255,.25);border-color:#6C63FF}
.topic-card .tc-icon{font-size:1.6rem;display:block;margin-bottom:4px}
.topic-card .tc-label{font-size:.88rem;font-weight:600;color:#fff;display:block}
.topic-card .tc-sub{font-size:.73rem;color:rgba(255,255,255,.4);display:block;margin-top:2px}

/* Buttons */
.btn-primary{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:14px 40px;font-size:1rem;font-weight:700;font-family:var(--font);
  color:#fff;background:var(--primary);
  border:none;border-radius:28px;cursor:pointer;
  transition:all .2s;
  box-shadow:0 4px 20px rgba(108,99,255,.35);
}
.btn-primary:disabled{opacity:.4;cursor:not-allowed;box-shadow:none}
.btn-primary:not(:disabled):hover{background:var(--primary-hover);transform:translateY(-1px);box-shadow:0 6px 28px rgba(108,99,255,.45)}

.btn-start{margin:28px auto 0;display:flex}

.btn-back{
  position:fixed;bottom:24px;left:24px;
  display:none;align-items:center;gap:4px;
  padding:8px 16px;border-radius:20px;
  background:rgba(255,255,255,.1);backdrop-filter:blur(8px);
  border:1px solid rgba(255,255,255,.15);
  color:rgba(255,255,255,.7);font-size:.85rem;font-weight:500;
  font-family:var(--font);cursor:pointer;transition:all .2s;
}
.btn-back:hover{background:rgba(255,255,255,.18);color:#fff}
.btn-back.visible{display:inline-flex}

.btn-icon{
  width:38px;height:38px;border-radius:50%;
  border:none;background:transparent;
  color:var(--text2);cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  transition:all .15s;
}
.btn-icon:hover{background:var(--primary-light);color:var(--primary)}

/* ===== Lesson Layout ===== */
.lesson{
  height:100%;display:flex;flex-direction:column;
  background:var(--bg);
}

.lesson-header{
  display:flex;align-items:center;justify-content:space-between;
  padding:10px 16px;background:var(--surface);
  border-bottom:1px solid var(--border);
  flex-shrink:0;
}
.lh-left{display:flex;align-items:center;gap:10px}
.lh-right{display:flex;align-items:center;gap:8px}
.lh-info{display:flex;flex-direction:column}
.lh-lang{font-weight:700;font-size:.92rem}
.lh-topic{font-size:.78rem;color:var(--text2)}

.xp-pill{
  display:inline-flex;align-items:center;gap:4px;
  padding:4px 12px;border-radius:16px;
  background:linear-gradient(135deg,#FDE68A,#F59E0B);
  color:#78350F;font-size:.78rem;font-weight:700;
}

/* Avatar Strip */
.avatar-strip{
  display:flex;align-items:center;gap:10px;
  padding:10px 16px;background:var(--surface);
  border-bottom:1px solid var(--border);flex-shrink:0;
}
.avatar-box{width:48px;height:48px;position:relative}
.avatar-box img,.avatar-box svg{width:100%;height:100%}
.avatar-label{font-weight:700;font-size:.9rem;color:var(--teacher-color)}

.avatar-box.speaking{animation:bob .45s ease-in-out infinite alternate}
@keyframes bob{from{transform:translateY(0)}to{transform:translateY(-3px)}}

/* Chat */
.chat-scroll{
  flex:1;overflow-y:auto;padding:16px;
  scroll-behavior:smooth;
}
.chat-inner{
  display:flex;flex-direction:column;gap:10px;
  max-width:680px;margin:0 auto;
}

.msg{
  max-width:82%;padding:12px 16px;
  border-radius:var(--r);line-height:1.6;
  font-size:.92rem;word-wrap:break-word;
  animation:msgIn .25s ease;
}
@keyframes msgIn{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}

.msg.tutor{
  align-self:flex-start;
  background:var(--surface);
  border:1px solid var(--border);
  border-bottom-left-radius:4px;
  box-shadow:var(--shadow-sm);
}
.msg.student{
  align-self:flex-end;
  background:var(--primary);color:#fff;
  border-bottom-right-radius:4px;
}

/* Cultural Note */
.cultural-note{
  background:linear-gradient(135deg,#FFFBEB,#FEF3C7);
  border-left:3px solid var(--warning);
  padding:10px 14px;border-radius:0 var(--r-sm) var(--r-sm) 0;
  margin:8px 0;font-size:.88rem;
}
.cultural-note-title{font-weight:700;color:#B45309;font-size:.8rem;margin-bottom:3px}

/* Dialogue */
.dialogue-block{
  background:var(--primary-light);border-left:3px solid var(--primary);
  padding:10px 14px;border-radius:0 var(--r-sm) var(--r-sm) 0;
  margin:8px 0;font-size:.88rem;
}

/* Sentence Builder */
.sentence-builder{
  background:#F0FDF4;border-radius:var(--r-sm);
  padding:12px 14px;margin:8px 0;
}
.sentence-builder-title{font-weight:600;font-size:.82rem;color:#166534;margin-bottom:8px}

.word-tiles{display:flex;flex-wrap:wrap;gap:6px}
.word-tile{
  padding:5px 12px;background:#fff;border:2px solid #86EFAC;
  border-radius:6px;cursor:grab;font-size:.88rem;
  user-select:none;transition:all .15s;
}
.word-tile:hover{background:#DCFCE7}
.word-tile.placed{opacity:.35;pointer-events:none}

.sentence-drop-zone{
  min-height:40px;border:2px dashed #86EFAC;
  border-radius:8px;padding:6px;margin-top:8px;
  display:flex;flex-wrap:wrap;gap:5px;
}
.sentence-drop-zone.correct{border-color:var(--success);background:#F0FDF4}

.placed-word{
  padding:4px 10px;background:var(--success);color:#fff;
  border-radius:5px;font-size:.88rem;cursor:pointer;
}

.sentence-builder-actions{margin-top:8px;display:flex;gap:6px}
.btn-check-sentence,.btn-reset-sentence{
  padding:5px 14px;border-radius:6px;border:none;
  font-size:.82rem;cursor:pointer;font-family:var(--font);
  transition:all .15s;
}
.btn-check-sentence{background:var(--success);color:#fff}
.btn-check-sentence:hover{background:#16A34A}
.btn-reset-sentence{background:var(--border);color:var(--text2)}

/* Typing Indicator */
.typing-indicator{
  align-self:flex-start;display:flex;align-items:center;gap:5px;
  padding:14px 20px;background:var(--surface);
  border:1px solid var(--border);
  border-radius:var(--r);border-bottom-left-radius:4px;
  box-shadow:var(--shadow-sm);
}
.typing-dot{
  width:7px;height:7px;border-radius:50%;
  background:var(--text3);
  animation:bounce 1.2s ease-in-out infinite;
}
.typing-dot:nth-child(2){animation-delay:.15s}
.typing-dot:nth-child(3){animation-delay:.3s}
@keyframes bounce{0%,60%,100%{transform:translateY(0);opacity:.35}30%{transform:translateY(-5px);opacity:1}}

/* Input Dock */
.input-dock{
  padding:10px 16px 14px;background:var(--surface);
  border-top:1px solid var(--border);flex-shrink:0;
}
.input-row{
  display:flex;align-items:center;gap:6px;
  max-width:680px;margin:0 auto;
  background:var(--bg);border-radius:24px;
  padding:4px 6px;border:1.5px solid var(--border);
  transition:border-color .2s;
}
.input-row:focus-within{border-color:var(--primary)}

.input-row input{
  flex:1;border:none;background:transparent;
  font-family:var(--font);font-size:.92rem;
  padding:9px 8px;outline:none;color:var(--text);
}

.btn-mic{color:var(--text3)}
.btn-mic.recording{color:var(--danger);animation:pulse 1s ease infinite}
@keyframes pulse{0%,100%{transform:scale(1)}50%{transform:scale(1.15)}}
.btn-send{color:var(--primary)}

/* ===== Responsive ===== */
@media(max-width:640px){
  .onboarding{padding:20px 12px 36px}
  .ob-logo{font-size:1.3rem}
  .ob-title{font-size:1.2rem}
  .lang-grid{grid-template-columns:repeat(auto-fill,minmax(105px,1fr))}
  .level-grid,.teacher-grid{grid-template-columns:1fr}
  .teacher-card{flex-direction:column;align-items:center;text-align:center}
  .msg{max-width:90%}
  .avatar-box{width:40px;height:40px}
}