/* ========================================================================
   InfiCode — Design tokens & global styles
   Palette (fixed by brief): Primary #2563EB, Secondary #7C3AED,
   Accent #06B6D4, Background #0F172A, Cards #1E293B, Text #F8FAFC
   ======================================================================== */

:root{
  --primary:#2563EB;
  --primary-soft:#3B82F6;
  --secondary:#7C3AED;
  --accent:#06B6D4;
  --bg:#0F172A;
  --bg-elevated:#111C34;
  --card:#1E293B;
  --card-hover:#243247;
  --text:#F8FAFC;
  --text-muted:#94A3B8;
  --text-faint:#64748B;
  --border:rgba(248,250,252,0.08);
  --border-strong:rgba(248,250,252,0.14);
  --success:#22C55E;
  --danger:#EF4444;
  --warning:#F59E0B;

  --font-display:'Space Grotesk', sans-serif;
  --font-body:'Inter', sans-serif;
  --font-mono:'JetBrains Mono', monospace;

  --radius-sm:8px;
  --radius-md:14px;
  --radius-lg:22px;
  --radius-pill:999px;

  --shadow-soft:0 8px 30px rgba(0,0,0,0.35);
  --shadow-glow:0 0 0 1px rgba(37,99,235,0.25), 0 12px 40px rgba(37,99,235,0.18);

  --sidenav-w:264px;
  --chat-history-w:280px;
  --chat-font-size:16px;

  --grad-primary:linear-gradient(135deg,#2563EB 0%,#7C3AED 100%);
  --grad-accent:linear-gradient(135deg,#06B6D4 0%,#2563EB 100%);
}

/* Light theme override */
body.theme-light{
  --bg:#F1F5F9;
  --bg-elevated:#E2E8F0;
  --card:#FFFFFF;
  --card-hover:#F8FAFC;
  --text:#0F172A;
  --text-muted:#475569;
  --text-faint:#64748B;
  --border:rgba(15,23,42,0.08);
  --border-strong:rgba(15,23,42,0.14);
  --shadow-soft:0 8px 30px rgba(15,23,42,0.08);
}

*,*::before,*::after{ box-sizing:border-box; }
html{ scroll-behavior:smooth; }
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:var(--font-body);
  -webkit-font-smoothing:antialiased;
  transition:background .3s ease, color .3s ease;
}
h1,h2,h3,h4{
  font-family:var(--font-display);
  margin:0 0 .4em 0;
  letter-spacing:-0.02em;
  font-weight:600;
}
p{ margin:0 0 1em 0; color:var(--text-muted); line-height:1.65; }
a{ color:var(--accent); }
button{ font-family:inherit; cursor:pointer; }
code, pre{ font-family:var(--font-mono); }
::selection{ background:var(--primary); color:#fff; }

@media (prefers-reduced-motion: reduce){
  *{ animation-duration:0.001ms !important; animation-iteration-count:1 !important; transition-duration:0.001ms !important; }
}

/* Scrollbars */
::-webkit-scrollbar{ width:10px; height:10px; }
::-webkit-scrollbar-track{ background:transparent; }
::-webkit-scrollbar-thumb{ background:var(--border-strong); border-radius:99px; }
::-webkit-scrollbar-thumb:hover{ background:var(--text-faint); }

/* ========================================================================
   Buttons & inputs
   ======================================================================== */
.btn{
  display:inline-flex; align-items:center; gap:.55em;
  padding:.72em 1.3em;
  border-radius:var(--radius-pill);
  border:1px solid transparent;
  font-weight:600; font-size:.92rem;
  transition:transform .15s ease, box-shadow .2s ease, background .2s ease, border-color .2s ease;
  white-space:nowrap;
}
.btn:active{ transform:scale(0.97); }
.btn-block{ width:100%; justify-content:center; }
.btn-primary{
  background:var(--grad-primary); color:#fff;
  box-shadow:0 6px 20px rgba(37,99,235,0.35);
}
.btn-primary:hover{ box-shadow:0 8px 26px rgba(37,99,235,0.5); }
.btn-secondary{
  background:var(--card); color:var(--text); border-color:var(--border-strong);
}
.btn-secondary:hover{ background:var(--card-hover); }
.btn-ghost{
  background:transparent; color:var(--text); border-color:var(--border-strong);
}
.btn-ghost:hover{ background:var(--card); border-color:var(--primary); }
.btn-danger{
  background:rgba(239,68,68,0.12); color:#FCA5A5; border-color:rgba(239,68,68,0.35);
}
.btn-danger:hover{ background:rgba(239,68,68,0.2); }
.btn:disabled{ opacity:.45; cursor:not-allowed; transform:none; }

.icon-btn{
  width:38px; height:38px; display:inline-flex; align-items:center; justify-content:center;
  border-radius:var(--radius-sm); border:1px solid var(--border);
  background:var(--card); color:var(--text-muted);
  transition:all .15s ease;
}
.icon-btn:hover{ color:var(--text); border-color:var(--primary); background:var(--card-hover); }

.text-input{
  flex:1; padding:.75em 1em; border-radius:var(--radius-sm);
  border:1px solid var(--border-strong); background:var(--bg-elevated); color:var(--text);
  font-family:var(--font-mono); font-size:.9rem;
  outline:none; transition:border-color .15s ease, box-shadow .15s ease;
}
.text-input:focus{ border-color:var(--primary); box-shadow:0 0 0 3px rgba(37,99,235,0.2); }

/* Visible keyboard focus */
button:focus-visible, .nav-item:focus-visible, .text-input:focus-visible, textarea:focus-visible{
  outline:2px solid var(--accent); outline-offset:2px;
}

/* ========================================================================
   Glass card
   ======================================================================== */
.glass-card{
  background:linear-gradient(180deg, var(--card) 0%, rgba(30,41,59,0.7) 100%);
  border:1px solid var(--border);
  border-radius:var(--radius-lg);
  backdrop-filter:blur(14px);
  -webkit-backdrop-filter:blur(14px);
  box-shadow:var(--shadow-soft);
}
body.theme-light .glass-card{
  background:linear-gradient(180deg, #FFFFFF 0%, #F8FAFC 100%);
}

/* ========================================================================
   App shell
   ======================================================================== */
.app-shell{ display:flex; min-height:100vh; }

.sidenav{
  width:var(--sidenav-w); flex-shrink:0;
  background:var(--bg-elevated);
  border-right:1px solid var(--border);
  display:flex; flex-direction:column;
  padding:22px 16px;
  position:sticky; top:0; height:100vh;
  z-index:40;
}

.brand{ display:flex; align-items:center; gap:12px; padding:6px 8px 26px 8px; }
.brand-mark{
  width:40px; height:40px; border-radius:11px;
  background:var(--grad-primary);
  display:flex; align-items:center; justify-content:center;
  font-family:var(--font-mono); font-weight:700; color:#fff; font-size:.95rem;
  box-shadow:0 6px 18px rgba(37,99,235,0.4);
  flex-shrink:0;
}
.brand-mark .bracket{ opacity:.9; }
.brand-mark.large{ width:72px; height:72px; border-radius:18px; font-size:1.6rem; margin:0 auto 20px; }
.brand-mark-img{ width:42px; height:42px; object-fit:contain; flex-shrink:0; }
.brand-mark-img.small{ width:32px; height:32px; }
.about-logo{ width:min(360px, 80%); height:auto; margin:0 auto 22px; display:block; }
body.theme-light .about-logo{ filter:none; }
.brand-text{ display:flex; flex-direction:column; line-height:1.2; }
.brand-name{ font-family:var(--font-display); font-weight:700; font-size:1.15rem; }
.brand-name em{ font-style:normal; color:var(--accent); }
.brand-name.small{ font-size:1rem; }
.brand-tag{ font-size:.68rem; color:var(--text-faint); letter-spacing:.04em; text-transform:uppercase; }

.nav-list{ display:flex; flex-direction:column; gap:4px; flex:1; overflow-y:auto; }
.nav-item{
  display:flex; align-items:center; gap:12px;
  padding:11px 14px; border-radius:var(--radius-sm);
  background:transparent; border:1px solid transparent; color:var(--text-muted);
  font-size:.9rem; font-weight:500; text-align:left;
  transition:all .15s ease;
}
.nav-item i{ width:18px; text-align:center; color:var(--text-faint); transition:color .15s ease; }
.nav-item:hover{ background:var(--card); color:var(--text); }
.nav-item:hover i{ color:var(--accent); }
.nav-item.active{
  background:linear-gradient(135deg, rgba(37,99,235,0.18), rgba(124,58,237,0.14));
  color:var(--text); border-color:rgba(37,99,235,0.35);
}
.nav-item.active i{ color:var(--primary-soft); }
.nav-divider{ height:1px; background:var(--border); margin:10px 6px; }

.sidenav-footer{ padding-top:14px; display:flex; flex-direction:column; gap:10px; }
.lang-switcher{ display:grid; grid-template-columns:repeat(4,1fr); gap:5px; }
.lang-opt{
  padding:7px 4px; border-radius:8px; background:var(--card); border:1px solid var(--border);
  color:var(--text-faint); font-size:.72rem; font-weight:700; letter-spacing:.02em;
  font-family:var(--font-mono); transition:all .15s ease;
}
.lang-opt:hover{ color:var(--text); border-color:var(--border-strong); }
.lang-opt.active{ background:rgba(37,99,235,0.18); border-color:var(--primary); color:var(--text); }
.status-pill{
  display:flex; align-items:center; gap:8px;
  font-size:.72rem; color:var(--text-faint);
  background:var(--card); border:1px solid var(--border);
  padding:9px 12px; border-radius:var(--radius-pill);
  font-family:var(--font-mono);
}
.dot{ width:7px; height:7px; border-radius:50%; }
.dot-live{ background:var(--success); box-shadow:0 0 8px var(--success); animation:pulse 2s infinite; }
@keyframes pulse{ 0%,100%{ opacity:1; } 50%{ opacity:.4; } }

.mobile-topbar{ display:none; }
.nav-scrim{ display:none; }

/* ========================================================================
   Main area & generic page layout
   ======================================================================== */
.main-area{ flex:1; min-width:0; padding:36px 44px 60px; max-width:1280px; margin:0 auto; width:100%; }
.page{ display:none; animation:fadeUp .45s ease; }
.page.active{ display:block; }
@keyframes fadeUp{ from{ opacity:0; transform:translateY(10px); } to{ opacity:1; transform:translateY(0); } }

.page-header{ margin-bottom:28px; }
.page-subdesc{ max-width:560px; }

.section-label{
  display:flex; align-items:center; gap:10px;
  font-family:var(--font-mono); font-size:.78rem; color:var(--text-faint);
  text-transform:uppercase; letter-spacing:.08em;
  margin:52px 0 18px;
}
.section-label span{
  color:var(--accent); border:1px solid var(--border-strong);
  padding:2px 8px; border-radius:6px; font-weight:600;
}

/* ========================================================================
   HOME — Hero
   ======================================================================== */
.hero{
  display:grid; grid-template-columns:1.1fr 1fr; gap:48px; align-items:center;
  padding-top:12px;
}
.eyebrow{
  display:inline-flex; align-items:center; gap:8px;
  font-family:var(--font-mono); font-size:.78rem; color:var(--accent);
  background:rgba(6,182,212,0.1); border:1px solid rgba(6,182,212,0.3);
  padding:6px 12px; border-radius:var(--radius-pill); margin-bottom:20px;
}
.eyebrow-dot{ width:6px; height:6px; border-radius:50%; background:var(--accent); box-shadow:0 0 8px var(--accent); }
.hero-title{ font-size:clamp(2.1rem, 4vw, 3.2rem); line-height:1.12; margin-bottom:20px; }
.typed-line{
  background:var(--grad-primary); -webkit-background-clip:text; background-clip:text; color:transparent;
}
.cursor-blink{ color:var(--accent); animation:blink 1s step-end infinite; }
@keyframes blink{ 50%{ opacity:0; } }
.hero-desc{ font-size:1.02rem; max-width:480px; margin-bottom:30px; }
.hero-actions{ display:flex; gap:14px; flex-wrap:wrap; }

.hero-visual{ position:relative; }
.code-window{
  background:#0B1220; border:1px solid var(--border-strong);
  border-radius:var(--radius-md); overflow:hidden;
  box-shadow:var(--shadow-glow);
  transform:perspective(1000px) rotateY(-4deg) rotateX(2deg);
  animation:floatSlow 6s ease-in-out infinite;
}
@keyframes floatSlow{ 0%,100%{ transform:perspective(1000px) rotateY(-4deg) rotateX(2deg) translateY(0); } 50%{ transform:perspective(1000px) rotateY(-4deg) rotateX(2deg) translateY(-10px); } }
.code-window-bar{
  display:flex; align-items:center; gap:7px;
  padding:12px 14px; background:#0F1A2E; border-bottom:1px solid var(--border);
}
.wdot{ width:11px; height:11px; border-radius:50%; }
.wdot-red{ background:#EF4444; } .wdot-yellow{ background:#F59E0B; } .wdot-green{ background:#22C55E; }
.code-window-title{ margin-left:8px; font-family:var(--font-mono); font-size:.75rem; color:var(--text-faint); }
.code-window-body{
  margin:0; padding:20px; font-size:.84rem; line-height:1.7; color:#CBD5E1; overflow-x:auto;
}
.tk-kw{ color:#7C3AED; font-weight:600; } .tk-fn{ color:#06B6D4; } .tk-str{ color:#22C55E; }

.floating-chip{
  position:absolute; display:flex; align-items:center; gap:7px;
  background:var(--card); border:1px solid var(--border-strong);
  padding:8px 14px; border-radius:var(--radius-pill); font-size:.8rem; font-weight:600;
  box-shadow:var(--shadow-soft); animation:floatChip 5s ease-in-out infinite;
}
.chip-1{ top:-14px; right:30px; animation-delay:.2s; }
.chip-2{ bottom:40px; left:-24px; animation-delay:1s; }
.chip-3{ bottom:-16px; right:60px; animation-delay:1.8s; }
@keyframes floatChip{ 0%,100%{ transform:translateY(0); } 50%{ transform:translateY(-9px); } }

/* Feature grid */
.feature-grid{ display:grid; grid-template-columns:repeat(4,1fr); gap:18px; }
.feature-card{ padding:26px 22px; transition:transform .2s ease, border-color .2s ease; }
.feature-card:hover{ transform:translateY(-4px); border-color:rgba(37,99,235,0.4); }
.feature-icon{
  width:44px; height:44px; border-radius:12px; display:flex; align-items:center; justify-content:center;
  background:color-mix(in srgb, var(--accent) 16%, transparent);
  color:var(--accent); font-size:1.1rem; margin-bottom:16px;
}
.feature-card h3{ font-size:1.02rem; margin-bottom:8px; }
.feature-card p{ font-size:.87rem; margin:0; }

/* Topics marquee */
.topics-marquee-wrap{ overflow:hidden; mask-image:linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent); }
.topics-marquee{ display:flex; gap:12px; width:max-content; animation:scrollX 32s linear infinite; }
.topics-marquee:hover{ animation-play-state:paused; }
@keyframes scrollX{ from{ transform:translateX(0); } to{ transform:translateX(-50%); } }
.topic-pill{
  font-family:var(--font-mono); font-size:.8rem; color:var(--text-muted);
  background:var(--card); border:1px solid var(--border); padding:9px 16px; border-radius:var(--radius-pill);
  white-space:nowrap;
}

/* ========================================================================
   CHAT PAGE
   ======================================================================== */
.chat-layout{
  display:grid; grid-template-columns:var(--chat-history-w) 1fr;
  gap:20px; height:calc(100vh - 96px); min-width:0;
}
.chat-history-panel{
  background:var(--card); border:1px solid var(--border); border-radius:var(--radius-lg);
  padding:16px; display:flex; flex-direction:column; gap:14px; overflow:hidden;
}
.chat-history-list{ overflow-y:auto; display:flex; flex-direction:column; gap:6px; flex:1; }
.history-item{
  display:flex; align-items:center; gap:10px;
  padding:10px 12px; border-radius:var(--radius-sm); cursor:pointer;
  border:1px solid transparent; color:var(--text-muted); font-size:.85rem;
  transition:all .15s ease;
}
.history-item i.hist-icon{ color:var(--text-faint); flex-shrink:0; }
.history-item span{ flex:1; overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.history-item .hist-del{
  opacity:0; color:var(--text-faint); flex-shrink:0; width:26px; height:26px;
  display:flex; align-items:center; justify-content:center; border-radius:6px;
}
.history-item:hover{ background:var(--card-hover); color:var(--text); }
.history-item:hover .hist-del{ opacity:1; }
.history-item .hist-del:hover{ color:var(--danger); background:rgba(239,68,68,0.12); }
.history-item.active{ background:rgba(37,99,235,0.14); border-color:rgba(37,99,235,0.35); color:var(--text); }
.history-empty{ color:var(--text-faint); font-size:.82rem; text-align:center; padding:20px 8px; }

.chat-main{
  background:var(--card); border:1px solid var(--border); border-radius:var(--radius-lg);
  display:flex; flex-direction:column; overflow:hidden; min-width:0;
}
.chat-toolbar{
  display:flex; align-items:center; justify-content:space-between;
  padding:14px 18px; border-bottom:1px solid var(--border);
}
.chat-toolbar-title{ display:flex; align-items:center; gap:10px; font-weight:600; font-size:.92rem; color:var(--text-muted); }
.chat-toolbar-title i{ color:var(--accent); }
.chat-toolbar-actions{ display:flex; gap:8px; }
.mobile-history-toggle{ display:none; }

.chat-messages{ flex:1; overflow-y:auto; padding:24px; display:flex; flex-direction:column; gap:20px; font-size:var(--chat-font-size); }

.chat-empty-state{
  margin:auto; text-align:center; max-width:520px; padding:20px; position:relative;
}
.empty-glow{
  position:absolute; inset:-40px; background:radial-gradient(circle, rgba(37,99,235,0.16), transparent 65%);
  z-index:-1;
}
.empty-icon{ font-size:2.4rem; color:var(--primary-soft); margin-bottom:14px; }
.chat-empty-state h3{ margin-bottom:8px; }
.suggestion-chips{ display:flex; flex-wrap:wrap; gap:10px; justify-content:center; margin-top:20px; }
.suggestion-chip{
  font-size:.82rem; padding:9px 15px; border-radius:var(--radius-pill);
  background:var(--bg-elevated); border:1px solid var(--border-strong); color:var(--text-muted);
  transition:all .15s ease;
}
.suggestion-chip:hover{ border-color:var(--primary); color:var(--text); }

.msg{ display:flex; gap:13px; max-width:840px; width:100%; min-width:0; animation:fadeUp .3s ease; }
.msg-user{ align-self:flex-end; flex-direction:row-reverse; }
.msg-bubble-wrap{ min-width:0; flex:1; }
.msg-avatar{
  width:34px; height:34px; border-radius:10px; flex-shrink:0;
  display:flex; align-items:center; justify-content:center; font-size:.85rem; color:#fff;
}
.msg-user .msg-avatar{ background:var(--grad-primary); }
.msg-ai .msg-avatar{ background:linear-gradient(135deg,#06B6D4,#2563EB); }
.msg-bubble{
  padding:13px 17px; border-radius:var(--radius-md);
  background:var(--bg-elevated); border:1px solid var(--border);
  line-height:1.65; overflow-wrap:anywhere; word-break:break-word;
}
.msg-user .msg-bubble{ background:rgba(37,99,235,0.16); border-color:rgba(37,99,235,0.3); }
.msg-bubble p{ color:var(--text); margin:0 0 .7em; }
.msg-bubble p:last-child{ margin-bottom:0; }
.msg-bubble ul, .msg-bubble ol{ color:var(--text); margin:.4em 0 .8em; padding-left:1.3em; }
.msg-bubble li{ margin-bottom:.3em; }
.msg-bubble h1,.msg-bubble h2,.msg-bubble h3{ font-size:1.05em; margin-top:.8em; }
.msg-bubble strong{ color:var(--text); }
.msg-bubble code.inline-code{
  background:rgba(148,163,184,0.15); padding:.15em .4em; border-radius:5px; font-size:.88em; color:var(--accent);
}
.msg-error .msg-bubble{ border-color:rgba(239,68,68,0.4); background:rgba(239,68,68,0.08); }
.msg-meta{ font-size:.7rem; color:var(--text-faint); margin-top:8px; display:flex; gap:10px; align-items:center; }
.msg-copy-btn{
  background:transparent; border:none; color:var(--text-faint); font-size:.72rem;
  display:inline-flex; align-items:center; gap:5px; padding:2px 4px;
}
.msg-copy-btn:hover{ color:var(--accent); }

/* Code block */
.code-block{
  margin:.8em 0; border-radius:var(--radius-sm); overflow:hidden;
  border:1px solid var(--border-strong); background:#0B1220;
}
.code-block-head{
  display:flex; align-items:center; justify-content:space-between;
  padding:8px 12px; background:#0F1A2E; border-bottom:1px solid var(--border);
  font-family:var(--font-mono); font-size:.72rem; color:var(--text-faint); text-transform:uppercase; letter-spacing:.04em;
}
.code-copy-btn{
  background:transparent; border:1px solid var(--border-strong); color:var(--text-muted);
  font-size:.7rem; padding:3px 9px; border-radius:6px; display:flex; align-items:center; gap:5px;
}
.code-copy-btn:hover{ color:var(--text); border-color:var(--accent); }
.code-block pre{ margin:0; padding:15px; overflow-x:auto; font-size:.83rem; line-height:1.6; color:#E2E8F0; }
.code-block .tk-kw, .code-window-body .tk-kw{ color:#C084FC; font-weight:600; }
.code-block .tk-fn, .code-window-body .tk-fn{ color:#22D3EE; }
.code-block .tk-str, .code-window-body .tk-str{ color:#4ADE80; }
.code-block .tk-num{ color:#FBBF24; }
.code-block .tk-cm{ color:#64748B; font-style:italic; }
.code-block .tk-attr{ color:#60A5FA; }

.chat-thinking{
  display:flex; align-items:center; gap:10px; padding:6px 24px 14px;
  color:var(--text-faint); font-size:.82rem;
}
.think-dot{ width:6px; height:6px; border-radius:50%; background:var(--accent); animation:thinkBounce 1.2s infinite; }
.think-dot:nth-child(2){ animation-delay:.15s; } .think-dot:nth-child(3){ animation-delay:.3s; }
@keyframes thinkBounce{ 0%,80%,100%{ opacity:.3; transform:translateY(0); } 40%{ opacity:1; transform:translateY(-4px); } }

.chat-input-bar{
  display:flex; gap:12px; align-items:flex-end;
  padding:16px 18px; border-top:1px solid var(--border);
}
.chat-input{
  flex:1; resize:none; max-height:160px;
  background:var(--bg-elevated); border:1px solid var(--border-strong); border-radius:var(--radius-md);
  color:var(--text); padding:12px 15px; font-family:var(--font-body); font-size:.92rem;
  outline:none; transition:border-color .15s ease;
}
.chat-input:focus{ border-color:var(--primary); }
.send-btn{
  width:46px; height:46px; border-radius:14px; flex-shrink:0; border:none;
  background:var(--grad-primary); color:#fff; font-size:1rem;
  display:flex; align-items:center; justify-content:center;
  box-shadow:0 6px 18px rgba(37,99,235,0.4); transition:transform .15s ease;
}
.send-btn:hover{ transform:scale(1.06); }
.send-btn:disabled{ opacity:.4; }

/* ========================================================================
   LESSONS
   ======================================================================== */
.lesson-grid{ display:grid; grid-template-columns:repeat(3,1fr); gap:18px; }
.lesson-card{
  padding:22px; cursor:pointer; transition:transform .2s ease, border-color .2s ease;
  display:flex; flex-direction:column; gap:10px;
}
.lesson-card:hover{ transform:translateY(-4px); border-color:rgba(6,182,212,0.4); }
.lesson-card-icon{
  width:42px; height:42px; border-radius:11px; display:flex; align-items:center; justify-content:center;
  background:rgba(6,182,212,0.14); color:var(--accent); font-size:1.05rem;
}
.lesson-card h3{ font-size:.98rem; margin:0; }
.lesson-card p{ font-size:.83rem; margin:0; }
.lesson-card .lesson-cta{ font-size:.78rem; color:var(--primary-soft); font-weight:600; display:flex; align-items:center; gap:6px; margin-top:auto; }

.modal-overlay{
  position:fixed; inset:0; background:rgba(4,8,20,0.7); backdrop-filter:blur(4px);
  display:flex; align-items:center; justify-content:center; z-index:100; padding:20px;
  opacity:0; pointer-events:none; transition:opacity .2s ease;
}
.modal-overlay.open{ opacity:1; pointer-events:auto; }
.modal-box{
  background:var(--card); border:1px solid var(--border-strong); border-radius:var(--radius-lg);
  max-width:560px; width:100%; padding:30px; max-height:80vh; overflow-y:auto;
  transform:translateY(16px) scale(.98); transition:transform .25s ease; box-shadow:var(--shadow-soft);
}
.modal-overlay.open .modal-box{ transform:translateY(0) scale(1); }
.modal-close{ float:right; }
.modal-box h3{ font-size:1.2rem; margin-bottom:12px; }
.modal-box p{ font-size:.9rem; }
.modal-actions{ margin-top:18px; display:flex; gap:10px; }

/* Dashboard (Home) */
.dashboard-grid{ display:grid; grid-template-columns:repeat(4,1fr); gap:16px; }
.dash-card{ padding:20px; display:flex; flex-direction:column; gap:6px; }
.dash-card-icon{
  width:36px; height:36px; border-radius:10px; display:flex; align-items:center; justify-content:center;
  background:rgba(37,99,235,0.16); color:var(--primary-soft); font-size:.95rem; margin-bottom:4px;
}
.dash-card .dash-value{ font-family:var(--font-display); font-size:1.5rem; font-weight:700; }
.dash-card .dash-label{ font-size:.78rem; color:var(--text-faint); }
.dash-card.dash-recommend{ grid-column:span 2; justify-content:space-between; }
.dash-recommend .dash-value{ font-size:1rem; }
.dash-empty{
  grid-column:1/-1; text-align:center; padding:24px; color:var(--text-faint); font-size:.88rem;
}

/* Lessons progress row */
.lessons-progress-row{ display:flex; align-items:center; gap:12px; margin-top:14px; max-width:420px; }

/* Quiz start flow */
.quiz-start{ padding:28px; max-width:720px; text-align:center; }
.quiz-start-actions{ display:flex; gap:12px; justify-content:center; flex-wrap:wrap; margin-top:16px; }
.quiz-generating{ display:flex; align-items:center; justify-content:center; gap:10px; margin-top:18px; color:var(--text-faint); font-size:.85rem; }
.quiz-weak-topics{ display:flex; gap:8px; flex-wrap:wrap; justify-content:center; margin:14px 0; }
.weak-topic-pill{
  font-family:var(--font-mono); font-size:.76rem; padding:6px 12px; border-radius:var(--radius-pill);
  background:rgba(239,68,68,0.1); border:1px solid rgba(239,68,68,0.3); color:#FCA5A5;
}

/* Larger modal for lesson/language detail */
.modal-box-lg{ max-width:680px; max-height:86vh; }
.modal-section{ margin-top:18px; }
.modal-section h4{ font-size:.88rem; text-transform:uppercase; letter-spacing:.04em; color:var(--accent); margin-bottom:8px; }
.modal-tag-row{ display:flex; gap:8px; flex-wrap:wrap; margin:10px 0 4px; }
.modal-tag{
  font-family:var(--font-mono); font-size:.74rem; padding:5px 11px; border-radius:var(--radius-pill);
  background:var(--bg-elevated); border:1px solid var(--border-strong); color:var(--text-muted);
}
.modal-list{ margin:0; padding-left:1.2em; color:var(--text-muted); font-size:.88rem; }
.modal-list li{ margin-bottom:6px; }
.modal-footer-actions{ display:flex; gap:10px; margin-top:20px; flex-wrap:wrap; }
.quiz-wrap{ padding:28px; max-width:720px; }
.quiz-topbar{ display:flex; align-items:center; gap:16px; margin-bottom:26px; }
.quiz-progress-track{ flex:1; height:6px; border-radius:99px; background:var(--bg-elevated); overflow:hidden; }
.quiz-progress-fill{ height:100%; background:var(--grad-primary); width:12.5%; transition:width .3s ease; }
.quiz-progress-label{ font-family:var(--font-mono); font-size:.78rem; color:var(--text-faint); white-space:nowrap; }
.quiz-score{ font-family:var(--font-mono); font-size:.82rem; color:var(--warning); display:flex; align-items:center; gap:5px; white-space:nowrap; }

.quiz-question{ font-size:1.1rem; margin-bottom:20px; }
.quiz-options{ display:flex; flex-direction:column; gap:10px; margin-bottom:8px; }
.quiz-option{
  text-align:left; padding:14px 16px; border-radius:var(--radius-sm);
  background:var(--bg-elevated); border:1px solid var(--border-strong); color:var(--text);
  font-size:.9rem; display:flex; align-items:center; gap:12px; transition:all .15s ease;
}
.quiz-option:hover{ border-color:var(--primary); }
.quiz-option .opt-letter{
  width:26px; height:26px; border-radius:7px; background:var(--card); flex-shrink:0;
  display:flex; align-items:center; justify-content:center; font-size:.76rem; font-weight:700; color:var(--text-muted);
}
.quiz-option.correct{ border-color:var(--success); background:rgba(34,197,94,0.12); }
.quiz-option.correct .opt-letter{ background:var(--success); color:#fff; }
.quiz-option.wrong{ border-color:var(--danger); background:rgba(239,68,68,0.12); }
.quiz-option.wrong .opt-letter{ background:var(--danger); color:#fff; }
.quiz-option:disabled{ cursor:default; }
.quiz-explain{
  margin-top:16px; padding:14px 16px; border-radius:var(--radius-sm);
  background:rgba(6,182,212,0.08); border:1px solid rgba(6,182,212,0.25); font-size:.85rem; color:var(--text-muted);
}
.quiz-nav{ display:flex; justify-content:space-between; margin-top:24px; }
.quiz-result{ max-width:480px; margin:24px auto 0; text-align:center; padding:40px 30px; }
.result-icon{ font-size:2.6rem; color:var(--warning); margin-bottom:12px; }

/* ========================================================================
   ALGORITHMS
   ======================================================================== */
.algo-layout{ display:grid; grid-template-columns:260px 1fr; gap:20px; align-items:start; min-width:0; }
.algo-list{ display:flex; flex-direction:column; gap:6px; min-width:0; }
.algo-list-item{
  display:flex; align-items:center; justify-content:space-between; gap:10px;
  padding:12px 14px; border-radius:var(--radius-sm); background:var(--card); border:1px solid var(--border);
  color:var(--text-muted); font-size:.85rem; transition:all .15s ease;
}
.algo-list-item:hover{ color:var(--text); border-color:var(--border-strong); }
.algo-list-item.active{ background:rgba(37,99,235,0.14); border-color:rgba(37,99,235,0.4); color:var(--text); }
.algo-badge{ font-family:var(--font-mono); font-size:.68rem; padding:2px 7px; border-radius:6px; background:var(--bg-elevated); color:var(--accent); }

.algo-detail{ padding:26px; min-height:360px; min-width:0; overflow:hidden; }
.algo-detail h3{ font-size:1.2rem; }
.algo-complexity{ display:flex; gap:10px; flex-wrap:wrap; margin:14px 0 18px; }
.complexity-pill{
  font-family:var(--font-mono); font-size:.76rem; padding:6px 12px; border-radius:var(--radius-pill);
  background:var(--bg-elevated); border:1px solid var(--border-strong); color:var(--text-muted);
}
.complexity-pill b{ color:var(--accent); }

/* ========================================================================
   PROGRAMMING LANGUAGES
   ======================================================================== */
.lang-grid{ display:grid; grid-template-columns:repeat(4,1fr); gap:16px; }
.lang-card{ padding:22px; text-align:center; transition:transform .2s ease, border-color .2s ease; }
.lang-card:hover{ transform:translateY(-4px); border-color:rgba(124,58,237,0.4); }
.lang-icon{ font-size:1.8rem; margin-bottom:12px; color:var(--primary-soft); }
.lang-card h3{ font-size:.95rem; margin-bottom:6px; }
.lang-card p{ font-size:.78rem; margin:0; }

/* ========================================================================
   SETTINGS
   ======================================================================== */
.settings-grid{ display:grid; grid-template-columns:repeat(2,1fr); gap:18px; }
.settings-card{ padding:24px; }
.settings-card h3{ display:flex; align-items:center; gap:9px; font-size:1rem; }
.settings-card h3 i{ color:var(--accent); }
.settings-desc{ font-size:.83rem; }
.settings-row{ display:flex; gap:10px; margin-bottom:14px; }
.save-toast{ margin-left:12px; color:var(--success); font-size:.82rem; }
.theme-toggle-row, .font-size-row{ display:flex; gap:10px; flex-wrap:wrap; }
#settingsLangRow .theme-opt{ flex:1 1 130px; font-size:.82rem; }
.theme-opt, .chip-btn{
  flex:1; padding:10px; border-radius:var(--radius-sm); background:var(--bg-elevated);
  border:1px solid var(--border-strong); color:var(--text-muted); font-size:.85rem;
  display:flex; align-items:center; justify-content:center; gap:8px; transition:all .15s ease;
}
.theme-opt.active, .chip-btn.active{ background:rgba(37,99,235,0.16); border-color:var(--primary); color:var(--text); }

/* ========================================================================
   ABOUT
   ======================================================================== */
.about-hero{ text-align:center; max-width:600px; margin:0 auto 40px; }
.about-lead{ font-size:1rem; }
.about-grid{ display:grid; grid-template-columns:repeat(3,1fr); gap:18px; margin-bottom:10px; }
.about-card{ padding:26px; text-align:center; }
.about-icon{ font-size:1.6rem; color:var(--accent); margin-bottom:14px; }
.about-card h3{ font-size:1rem; }
.about-card p{ font-size:.85rem; }
.stack-badges{ display:flex; gap:12px; flex-wrap:wrap; }
.stack-badge{
  display:inline-flex; align-items:center; gap:8px;
  padding:10px 16px; border-radius:var(--radius-pill);
  background:var(--card); border:1px solid var(--border-strong); font-size:.85rem; color:var(--text-muted);
}
.stack-badge i{ color:var(--accent); }

/* ========================================================================
   Toasts
   ======================================================================== */
.toast-container{
  position:fixed; bottom:24px; right:24px; display:flex; flex-direction:column; gap:10px; z-index:200;
}
.toast{
  display:flex; align-items:center; gap:10px;
  background:var(--card); border:1px solid var(--border-strong); color:var(--text);
  padding:13px 18px; border-radius:var(--radius-sm); font-size:.86rem;
  box-shadow:var(--shadow-soft); animation:toastIn .25s ease;
  min-width:220px;
}
.toast i{ color:var(--success); }
.toast.toast-error i{ color:var(--danger); }
.toast.toast-info i{ color:var(--accent); }
@keyframes toastIn{ from{ opacity:0; transform:translateX(30px); } to{ opacity:1; transform:translateX(0); } }
.toast.toast-out{ animation:toastOut .2s ease forwards; }
@keyframes toastOut{ to{ opacity:0; transform:translateX(30px); } }

/* ========================================================================
   Responsive
   ======================================================================== */
/* Responsive meta baseline */
html{ -webkit-text-size-adjust:100%; }
html, body{ overflow-x:hidden; width:100%; }
img{ max-width:100%; height:auto; }
.app-shell{ min-height:100vh; min-height:100dvh; }

/* ========================================================================
   Responsive — mobile-first refinements across all breakpoints
   ======================================================================== */

/* Large desktop: give a little more breathing room on huge screens */
@media (min-width:1440px){
  .main-area{ max-width:1360px; }
  .hero{ gap:64px; }
}

/* Small laptops / tablets landscape */
@media (max-width:1200px){
  .feature-grid{ grid-template-columns:repeat(2,1fr); }
}

@media (max-width:1080px){
  .lang-grid{ grid-template-columns:repeat(2,1fr); }
  .lesson-grid{ grid-template-columns:repeat(2,1fr); }
  .about-grid{ grid-template-columns:1fr; }
  .settings-grid{ grid-template-columns:1fr; }
  .hero{ grid-template-columns:1fr; gap:36px; }
  .hero-visual{ order:-1; max-width:440px; margin:0 auto; width:100%; }
  .algo-layout{ grid-template-columns:220px 1fr; }
  .dashboard-grid{ grid-template-columns:repeat(2,1fr); }
  .dash-card.dash-recommend{ grid-column:span 2; }
}

/* Tablets (portrait) & small laptops — nav collapses to drawer */
@media (max-width:860px){
  /* KRITIK TUZATISH: .app-shell standart holatda flex-direction:row bo'lgani
     uchun .mobile-topbar asosiy kontent yoniga qo'shimcha ustun bo'lib
     qo'shilib, sahifani ekran enidan kengaytirib yuborardi. Mobil holatda
     ustunlarni vertikal (column) tartibga o'tkazamiz. */
  .app-shell{ flex-direction:column; }

  .sidenav{
    position:fixed; left:0; top:0; transform:translateX(-100%);
    transition:transform .25s ease; box-shadow:0 0 40px rgba(0,0,0,0.5);
    height:100vh; height:100dvh;
    padding-top:max(22px, env(safe-area-inset-top));
  }
  .sidenav.open{ transform:translateX(0); }
  .mobile-topbar{
    display:flex; align-items:center; justify-content:space-between;
    padding:12px 16px; border-bottom:1px solid var(--border); background:var(--bg-elevated);
    position:sticky; top:0; z-index:30; width:100%;
    padding-top:max(12px, env(safe-area-inset-top));
  }
  .nav-scrim{ display:none; position:fixed; inset:0; background:rgba(0,0,0,0.5); z-index:35; }
  .nav-scrim.open{ display:block; }
  .main-area{ padding:22px 18px 50px; }
  .algo-layout{ grid-template-columns:1fr; }
  .algo-list{ flex-direction:row; overflow-x:auto; padding-bottom:6px; gap:8px; }
  .algo-list-item{ flex:0 0 auto; white-space:nowrap; }
  .chat-layout{
    grid-template-columns:1fr;
    height:calc(100vh - 150px);
    height:calc(100dvh - 150px);
  }
  .chat-history-panel{
    position:fixed; right:0; top:0; height:100vh; height:100dvh; width:min(280px, 82vw); z-index:45;
    transform:translateX(100%); transition:transform .25s ease; border-radius:0;
    padding-top:max(16px, env(safe-area-inset-top));
  }
  .chat-history-panel.open{ transform:translateX(0); }
  .mobile-history-toggle{ display:inline-flex; }
  .lang-grid, .lesson-grid{ grid-template-columns:repeat(2,1fr); }
}

/* Phones */
@media (max-width:640px){
  .feature-grid, .lang-grid, .lesson-grid{ grid-template-columns:1fr; }
  .dashboard-grid{ grid-template-columns:1fr; }
  .dash-card.dash-recommend{ grid-column:span 1; }
  .hero-title{ font-size:clamp(1.6rem, 7vw, 1.9rem); }
  .hero-desc{ font-size:.94rem; }
  .hero-actions .btn{ flex:1; justify-content:center; }
  .quiz-wrap{ padding:18px; }
  .stack-badges{ justify-content:center; }
  .section-label{ margin:38px 0 14px; }
  .code-window{ transform:none; animation:none; }
  .floating-chip{ display:none; }
  .msg{ max-width:100%; }
  .chat-messages{ padding:16px; gap:16px; }
  .chat-input-bar{ padding:12px; }
  .chat-toolbar{ padding:12px 14px; }
  .settings-row{ flex-wrap:wrap; }
  .about-hero{ padding:0 6px; }
  .code-block pre, .code-window-body{ font-size:.78rem; }
}

/* Very small phones */
@media (max-width:400px){
  .main-area{ padding:16px 14px 44px; }
  .brand-name{ font-size:1.05rem; }
  .nav-item{ padding:10px 12px; font-size:.86rem; }
  .btn{ padding:.68em 1.05em; font-size:.86rem; }
  .glass-card{ border-radius:var(--radius-md); }
  .feature-card, .lesson-card, .lang-card, .about-card{ padding:18px; }
  .settings-card{ padding:18px; }
  .suggestion-chips{ gap:8px; }
  .suggestion-chip{ font-size:.76rem; padding:8px 12px; }
  .quiz-topbar{ flex-wrap:wrap; gap:8px; }
}

/* Short / landscape mobile screens — keep chat usable when keyboard is open */
@media (max-height:480px) and (orientation:landscape){
  .hero{ padding-top:0; }
  .code-window{ display:none; }
  .floating-chip{ display:none; }
  .chat-layout{ height:calc(100vh - 60px); height:calc(100dvh - 60px); }
  .section-label{ margin:28px 0 12px; }
}

/* Touch devices: hover-only affordances must always be visible/usable */
@media (hover:none){
  .history-item .hist-del{ opacity:1; }
  .nav-item, .icon-btn, .quiz-option, .suggestion-chip, .lesson-card, .lang-card{ -webkit-tap-highlight-color:transparent; }
}

/* Respect safe areas on notched devices for bottom-anchored input bar */
.chat-input-bar{ padding-bottom:max(16px, env(safe-area-inset-bottom)); }