:root{
  --paper:#FBF7F0;
  --paper-2:#FFFDF8;
  --ink:#1C2A26;
  --ink-soft:#4A5C55;
  --muted:#7C8A83;
  --line:#E4DCCD;
  --accent:#0E6E5C;
  --accent-soft:#DDEDE7;
  --warm:#C25E2E;
  --warm-soft:#F7E3D8;
  --shadow:0 10px 30px rgba(28,42,38,.07);
  --radius:18px;
}
*{box-sizing:border-box}
[hidden]{display:none !important}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:
    radial-gradient(900px 500px at 85% -10%, #EAF2EC 0%, transparent 60%),
    radial-gradient(700px 400px at -10% 10%, #F8EADF 0%, transparent 55%),
    var(--paper);
  color:var(--ink);
  font-family:"Noto Sans SC","Microsoft YaHei","PingFang SC","Noto Sans Lao","Leelawadee UI",system-ui,-apple-system,"Segoe UI",sans-serif;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
.wrap{width:min(1120px,calc(100% - 40px));margin-inline:auto}

/* top bar */
.topbar{position:sticky;top:0;z-index:40;backdrop-filter:blur(14px);background:rgba(251,247,240,.82);border-bottom:1px solid var(--line)}
.topbar-inner{display:flex;align-items:center;justify-content:space-between;height:68px}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:inherit}
.brand-mark{width:40px;height:40px;border-radius:12px;background:var(--accent);color:#fff;display:grid;place-items:center;font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-weight:700;font-size:20px}
.brand-text{display:flex;flex-direction:column;line-height:1.15}
.brand-text strong{font-size:17px;letter-spacing:.02em}
.brand-text small{font-family:"Noto Sans Lao","Leelawadee UI","Phetsarath OT","Lao UI",sans-serif;font-size:12px;color:var(--muted)}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:1px solid transparent;border-radius:999px;padding:10px 18px;font:inherit;font-weight:600;font-size:14px;cursor:pointer;text-decoration:none;transition:transform .15s ease, background .2s ease, box-shadow .2s ease}
.btn:active{transform:translateY(1px)}
.btn.primary{background:var(--accent);color:#fff;box-shadow:0 6px 18px rgba(14,110,92,.22)}
.btn.primary:hover{background:#0B5B4C}
.btn.ghost{background:rgba(255,255,255,.7);border-color:var(--line);color:var(--ink)}
.btn.ghost:hover{background:#fff;border-color:#CFC5B4}
.btn.wide{width:100%}

/* hero */
.hero{display:grid;grid-template-columns:1.35fr .8fr;gap:48px;align-items:center;padding:64px 0 40px}
.eyebrow{margin:0 0 10px;font-size:12px;letter-spacing:.18em;text-transform:uppercase;color:var(--warm);font-weight:700}
.hero h1{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:clamp(30px,4.4vw,52px);line-height:1.18;margin:0 0 16px;letter-spacing:-.01em}
.hero-sub{margin:0 0 26px;color:var(--ink-soft);font-size:16px;max-width:34em}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap}
.hero-card{
  justify-self:end;width:100%;max-width:320px;background:var(--paper-2);border:1px solid var(--line);
  border-radius:26px;padding:28px 26px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:4px;
  transform:rotate(-1.5deg);position:relative;
}
.hero-card::after{content:"";position:absolute;inset:10px;border:1px dashed #E9DFCC;border-radius:18px;pointer-events:none}
.hc-py{font-size:15px;color:var(--accent);letter-spacing:.06em}
.hc-zh{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:64px;font-weight:700;line-height:1.2;margin:2px 0}
.hc-lo{font-family:"Noto Sans Lao","Leelawadee UI","Phetsarath OT","Lao UI",sans-serif;font-size:20px;color:var(--warm)}
.hc-line{height:1px;background:var(--line);margin:14px 0 10px}
.hc-tip{font-size:13px;color:var(--muted)}

/* tones */
.tones{padding:14px 0 8px}
.tone-head h2{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:22px;margin:0 0 2px}
.tone-head p{margin:0 0 18px;color:var(--muted);font-size:14px;font-family:"Noto Sans Lao","Noto Sans SC","Microsoft YaHei","PingFang SC",sans-serif}
.tone-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}
.tone{background:var(--paper-2);border:1px solid var(--line);border-radius:14px;padding:14px 12px;text-align:center}
.tone b{display:block;font-size:24px;line-height:1.3}
.tone span{font-size:12px;color:var(--muted);display:block}
.tone .lo{font-family:"Noto Sans Lao","Leelawadee UI","Phetsarath OT","Lao UI",sans-serif;color:var(--warm);font-size:12px}

/* mode switch */
.modes{display:inline-flex;background:#F1EADD;border:1px solid var(--line);border-radius:999px;padding:4px;gap:4px;margin-bottom:6px;width:100%;max-width:520px}
.mode{flex:1;border:0;background:transparent;color:var(--ink-soft);font:inherit;font-size:13px;font-weight:600;padding:9px 14px;border-radius:999px;cursor:pointer;white-space:nowrap;transition:.18s}
.mode:hover{color:var(--ink)}
.mode.active{background:var(--paper-2);color:var(--accent);box-shadow:0 2px 8px rgba(28,42,38,.08)}

/* lesson banner */
.lesson-banner{display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap;background:linear-gradient(135deg,#0E6E5C,#168A72);color:#fff;border-radius:18px;padding:18px 22px;margin-top:14px;box-shadow:0 12px 30px rgba(14,110,92,.18)}
.lesson-banner strong{display:block;font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:21px;line-height:1.3;margin:2px 0}
.lb-tag{font-size:11px;letter-spacing:.1em;text-transform:uppercase;opacity:.85}
.lb-sub{font-size:12px;opacity:.8}
.lesson-banner .btn.primary{background:#fff;color:var(--accent);box-shadow:none}
.lesson-banner .btn.primary:hover{background:#F1F8F5}

/* lesson list */
.lesson-list{margin-top:26px}
.ll-head h2{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:20px;margin:0 0 4px}
.ll-head p{margin:0 0 14px;font-size:13px;color:var(--muted)}
.ll-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(190px,1fr));gap:10px}
.ll-item{display:block;text-decoration:none;background:var(--paper-2);border:1px solid var(--line);border-radius:14px;padding:12px 14px;transition:.15s}
.ll-item:hover{border-color:var(--accent);transform:translateY(-1px)}
.ll-no{font-size:11px;letter-spacing:.08em;color:var(--accent);font-weight:700}
.ll-zh{display:block;font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:16px;margin:2px 0 2px}
.ll-py{display:block;font-size:12px;color:var(--muted)}

/* toolbar */
.toolbar{display:flex;align-items:center;gap:16px;flex-wrap:wrap;padding:34px 0 14px}

/* learning path */
.path{padding:10px 0 4px}
.path-head h2{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:22px;margin:0 0 2px}
.path-head p{margin:0 0 16px;color:var(--muted);font-size:14px}
.path-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:10px}
.path-card{position:relative;display:block;text-decoration:none;background:var(--paper-2);border:1px solid var(--line);border-radius:16px;padding:14px 16px 13px;transition:.15s;overflow:hidden}
.path-card:hover{border-color:var(--accent);transform:translateY(-2px);box-shadow:var(--shadow)}
.path-card .pc-step{position:absolute;right:12px;top:8px;font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:26px;font-weight:700;color:#EFE7D6}
.path-card strong{display:block;font-size:15px;margin:4px 0 2px;color:var(--ink)}
.path-card small{display:block;font-size:12px;color:var(--muted)}
.path-card em{display:block;font-style:normal;font-family:"Noto Sans Lao","Leelawadee UI","Phetsarath OT","Lao UI",sans-serif;font-size:12px;color:var(--warm);margin-top:6px}
.search-box{flex:1 1 320px;display:flex;align-items:center;gap:8px;background:var(--paper-2);border:1px solid var(--line);border-radius:999px;padding:11px 18px;box-shadow:0 2px 0 rgba(28,42,38,.02)}
.search-box:focus-within{border-color:var(--accent);box-shadow:0 0 0 4px var(--accent-soft)}
.search-ico{color:var(--muted);font-size:18px}
.search-box input{border:0;outline:0;background:transparent;font:inherit;font-size:15px;width:100%;color:var(--ink)}
.switches{display:flex;gap:8px;flex-wrap:wrap}
.switch{display:inline-flex;align-items:center;gap:7px;background:var(--paper-2);border:1px solid var(--line);border-radius:999px;padding:8px 14px;font-size:13px;cursor:pointer;user-select:none;color:var(--ink-soft)}
.switch input{accent-color:var(--accent);margin:0;width:15px;height:15px}
.switch:has(input:checked){background:var(--accent-soft);border-color:#BFDBD1;color:#0A5546}

/* cats */
.cats{display:flex;gap:8px;overflow-x:auto;padding:8px 0 4px;scrollbar-width:none}
.cats::-webkit-scrollbar{display:none}
.cat{white-space:nowrap;border:1px solid var(--line);background:transparent;color:var(--ink-soft);border-radius:999px;padding:7px 15px;font:inherit;font-size:13px;cursor:pointer}
.cat:hover{background:#fff}
.cat.active{background:var(--ink);color:#fff;border-color:var(--ink)}

/* progress */
.progress-wrap{padding:18px 0 6px}
.progress-meta{display:flex;justify-content:space-between;gap:12px;font-size:13px;color:var(--ink-soft);margin-bottom:8px}
.muted{color:var(--muted)}
.bar{height:8px;border-radius:99px;background:#EDE6D8;overflow:hidden}
.bar i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--accent),#4FAE97);border-radius:99px;transition:width .35s ease}

/* grid + cards */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:14px;padding:18px 0 56px}
.card{position:relative;background:var(--paper-2);border:1px solid var(--line);border-radius:var(--radius);padding:20px 20px 18px;box-shadow:0 2px 0 rgba(28,42,38,.02);transition:transform .18s ease,box-shadow .18s ease,border-color .18s ease;cursor:pointer}
.card:hover{transform:translateY(-3px);box-shadow:var(--shadow);border-color:#D6CAB4}
.card.learned{border-color:#BFDBD1;background:linear-gradient(180deg,#F7FCF9,var(--paper-2))}
.card-top{display:flex;justify-content:space-between;align-items:flex-start;gap:8px}
.zh{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:30px;font-weight:700;line-height:1.25;margin:0}
.py{margin:4px 0 0;color:var(--accent);font-size:14px;letter-spacing:.03em;min-height:1.2em}
.lo{margin:8px 0 0;font-family:"Noto Sans Lao","Leelawadee UI","Phetsarath OT","Lao UI",sans-serif;font-size:16px;color:var(--warm);line-height:1.5;min-height:1.2em}
.card-foot{display:flex;align-items:center;justify-content:space-between;margin-top:14px;padding-top:12px;border-top:1px solid #EFE8DA}
.cat-tag{font-size:11px;color:var(--muted);letter-spacing:.04em}
.card-btns{display:flex;gap:6px}
.icon-btn{width:34px;height:34px;border-radius:50%;border:1px solid var(--line);background:#fff;display:grid;place-items:center;cursor:pointer;font-size:14px;color:var(--ink-soft);transition:.15s}
.icon-btn:hover{border-color:var(--accent);color:var(--accent)}
.icon-btn.on{background:var(--accent);border-color:var(--accent);color:#fff}
.card.hide-py .py,.card.hide-lo .lo{visibility:hidden}
.empty{text-align:center;color:var(--muted);padding:40px 0 80px}

/* footer */
.footer{border-top:1px solid var(--line);padding:26px 0 40px;font-size:13px;color:var(--ink-soft)}
.footer p{margin:2px 0}
.foot-links{display:flex;flex-wrap:wrap;gap:8px 12px;margin:8px 0}
.foot-links a{color:var(--accent);text-decoration:none;font-size:13px}
.foot-links a:hover{text-decoration:underline}

/* quiz */
.quiz{position:fixed;inset:0;z-index:80;background:rgba(20,30,27,.45);backdrop-filter:blur(6px);display:grid;place-items:center;padding:20px}
.quiz[hidden]{display:none}
.quiz-panel{width:min(460px,100%);background:var(--paper-2);border-radius:24px;padding:20px 24px 18px;box-shadow:0 30px 80px rgba(0,0,0,.25);border:1px solid var(--line)}
.quiz-top{display:flex;justify-content:space-between;align-items:center;font-size:13px;color:var(--muted)}
.quiz-body{text-align:center;padding:8px 0 4px}
.quiz-label{font-size:13px;color:var(--muted);margin:4px 0 18px}
.quiz-zh{font-family:"Noto Serif SC","Songti SC","SimSun",serif;font-size:46px;font-weight:700;margin:0;line-height:1.25}
.quiz-py{color:var(--accent);margin:6px 0 22px;letter-spacing:.05em}
.quiz-lo{font-family:"Noto Sans Lao","Leelawadee UI","Phetsarath OT","Lao UI",sans-serif;color:var(--warm);font-size:22px;margin:18px 0 0}
.quiz-actions{display:flex;gap:10px;justify-content:center;margin-top:18px}
.quiz-actions .btn{flex:1}
.quiz-score{text-align:center;font-size:13px;color:var(--muted);margin:16px 0 0;border-top:1px solid var(--line);padding-top:12px}

@media (max-width:860px){
  .hero{grid-template-columns:1fr;gap:28px;padding:40px 0 24px}
  .hero-card{justify-self:start;transform:none;max-width:100%}
  .tone-grid{grid-template-columns:repeat(3,1fr)}
}
@media (max-width:520px){
  .wrap{width:calc(100% - 28px)}
  .topbar-inner{height:60px}
  .top-actions .btn{font-size:12px;padding:8px 12px}
  .hero h1{font-size:30px}
  .hc-zh{font-size:52px}
  .grid{grid-template-columns:1fr;padding-bottom:40px}
  .tone-grid{grid-template-columns:repeat(2,1fr)}
  .progress-meta .muted{display:none}
}