:root{--bg:#12141a;--bg-elevated:#1a1d27;--bg-card:#1e2230;--bg-hover:#262b3c;--border:rgba(255,255,255,.08);--border-strong:rgba(255,255,255,.14);--text:#e8e6e1;--text-muted:#9a96a0;--text-dim:#6b6772;--accent:#c4a574;--accent-soft:rgba(196,165,116,.15);--accent-hover:#d4b888;--new:#7a9ec2;--learn:#c4a574;--rev:#7aad8a;--danger:#c46b6b;--radius:12px;--radius-sm:8px;--shadow:0 8px 32px rgba(0,0,0,.4);--font:"DM Sans",system-ui,sans-serif;--serif:"Instrument Serif",Georgia,serif;--ease:160ms ease}
*{box-sizing:border-box}html,body{margin:0;background:var(--bg);color:var(--text);font:15px/1.5 var(--font);-webkit-tap-highlight-color:transparent}
a{color:var(--accent);text-decoration:none}a:hover{color:var(--accent-hover)}
h1,h2{font-family:var(--serif);font-weight:400;margin:0 0 .4em}h1{font-size:2rem}h2{font-size:1.6rem}h3{font-size:.8rem;text-transform:uppercase;letter-spacing:.08em;color:var(--text-muted);margin:1.6em 0 .6em;font-weight:600}
.muted{color:var(--text-muted)}.dim{color:var(--text-dim)}.small{font-size:.85rem}.center{text-align:center}.grow{flex:1}
code{background:var(--bg-hover);padding:1px 5px;border-radius:4px;font-size:.9em}
kbd{font:600 .7rem var(--font);opacity:.55;margin-left:6px;border:1px solid var(--border-strong);border-radius:4px;padding:0 4px}
.topbar{position:sticky;top:0;z-index:5;display:flex;align-items:center;gap:16px;padding:12px 20px;background:rgba(18,20,26,.85);backdrop-filter:blur(12px);border-bottom:1px solid var(--border)}
.brand{font-family:var(--serif);font-size:1.4rem;color:var(--text);display:flex;align-items:center;gap:8px}
.logo{display:inline-grid;place-items:center;width:30px;height:30px;border-radius:8px;background:var(--accent-soft);color:var(--accent);border:1px solid var(--accent)}
.nav{display:flex;gap:4px;margin-left:auto}.nav a{color:var(--text-muted);padding:6px 12px;border-radius:var(--radius-sm);display:flex;gap:6px;align-items:center;transition:var(--ease)}
.nav a:hover{background:var(--bg-hover);color:var(--text)}.nav a.active{color:var(--accent);background:var(--accent-soft)}
main{max-width:860px;margin:0 auto;padding:24px 20px 100px}
.panel{background:var(--bg-elevated);border:1px solid var(--border);border-radius:var(--radius);padding:20px;margin-bottom:16px}.narrow{max-width:620px;margin-left:auto;margin-right:auto}
.panel-head{display:flex;justify-content:space-between;align-items:center;gap:12px}.panel-head h3{margin:0}
.hero{display:flex;justify-content:space-between;align-items:center;gap:16px;margin:8px 0 20px}.hero h1{font-size:2.6rem;margin:0}.hero p{margin:0}
.btn{appearance:none;border:1px solid var(--border-strong);background:var(--bg-card);color:var(--text);font:500 .95rem var(--font);padding:10px 16px;border-radius:var(--radius-sm);cursor:pointer;transition:var(--ease);display:inline-flex;align-items:center;justify-content:center;gap:6px}
.btn:hover{background:var(--bg-hover)}.btn:disabled{opacity:.4;cursor:default}
.btn.primary{background:var(--accent);color:#1a1712;border-color:var(--accent)}.btn.primary:hover{background:var(--accent-hover)}
.btn.ghost{background:transparent}.btn.danger{color:var(--danger);border-color:rgba(196,107,107,.4);background:transparent}.btn.small{padding:5px 10px;font-size:.8rem}
.big-btn{padding:14px 26px;font-size:1.05rem}.icon-btn{background:none;border:0;color:var(--text-muted);font-size:1.1rem;cursor:pointer;padding:6px 8px;border-radius:6px}.icon-btn:hover{background:var(--bg-hover);color:var(--text)}
.row{display:flex;gap:8px;align-items:center;margin-top:14px}.row.wrap{flex-wrap:wrap}.stack{display:flex;flex-direction:column;gap:8px}
.pill{font-size:.7rem;padding:1px 8px;border-radius:99px;background:var(--bg-hover);color:var(--text-muted);vertical-align:middle;font-weight:500}
.deck-row{display:flex;align-items:center;gap:8px;padding:6px 0 6px calc(var(--depth)*18px);border-top:1px solid var(--border)}
.deck-name{flex:1;text-align:left;background:none;border:0;color:var(--text);font:500 1rem var(--font);cursor:pointer;padding:8px 0}.deck-name:hover{color:var(--accent)}
.counts,.legend{display:flex;gap:12px;font-variant-numeric:tabular-nums;font-weight:600;font-size:.9rem}.legend{font-weight:400;font-size:.75rem}
.counts span{min-width:22px;text-align:right}.c-new{color:var(--new)}.c-learn{color:var(--learn)}.c-rev{color:var(--rev)}
.birthdays .bday{display:flex;justify-content:space-between;gap:8px;padding:8px 0;border-top:1px solid var(--border)}.bday.today{color:var(--accent)}.birthdays h3{margin-top:0}
label{display:block;font-size:.85rem;color:var(--text-muted);margin:12px 0 0}label.check{display:flex;gap:8px;align-items:center}
input,select,textarea{width:100%;margin-top:4px;background:var(--bg);color:var(--text);border:1px solid var(--border-strong);border-radius:var(--radius-sm);padding:10px 12px;font:1rem var(--font)}
input[type=checkbox]{width:auto;margin:0}textarea{resize:vertical}input:focus,select:focus,textarea:focus{outline:none;border-color:var(--accent)}
.search{margin:8px 0 12px}.tags{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:12px}.tag{background:var(--bg-card);border:1px solid var(--border);color:var(--text-muted);border-radius:99px;padding:3px 10px;font-size:.78rem;cursor:pointer}.tag:hover{color:var(--accent)}
.list .item{display:flex;gap:10px;align-items:center;padding:12px;border-radius:var(--radius-sm);cursor:pointer;border-top:1px solid var(--border)}.list .item:hover{background:var(--bg-hover)}
.item-title{font-weight:500}.leech{color:var(--danger)}
.tabs{display:flex;gap:4px;margin:8px 0}.tab{background:none;border:1px solid var(--border);color:var(--text-muted);padding:7px 14px;border-radius:var(--radius-sm);cursor:pointer;font:500 .9rem var(--font)}.tab.active{color:var(--accent);border-color:var(--accent);background:var(--accent-soft)}
.file{cursor:pointer}
/* study */
.study{max-width:640px;margin:0 auto;display:flex;flex-direction:column;min-height:calc(100dvh - 170px)}
.study-top{display:flex;align-items:center;gap:10px;margin-bottom:12px}.study-top .muted{flex:1}
.tag-new{color:var(--new)}.tag-learning{color:var(--learn)}.tag-review{color:var(--rev)}
.flash{flex:1;background:var(--bg-card);border:1px solid var(--border);border-radius:16px;padding:32px 24px;box-shadow:var(--shadow);font-size:1.2rem;text-align:center;display:flex;flex-direction:column;justify-content:center;gap:8px;user-select:text;cursor:pointer;min-height:300px}
.flash.revealed{cursor:default}.flash hr{border:0;border-top:1px solid var(--border-strong);width:60%;margin:16px auto}
.flash .meta{margin-top:auto;padding-top:20px;font-size:.75rem}
.big{font-size:2.6rem;font-family:var(--serif);line-height:1.2}.big-ish{font-size:1.4rem}.reading{color:var(--accent);font-size:1.1rem}.meaning{font-size:1.25rem}.example,.extra{color:var(--text-muted);font-size:1rem;margin-top:10px}.hint{color:var(--text-dim);font-size:.85rem}
.label{text-transform:uppercase;font-size:.7rem;letter-spacing:.1em;color:var(--text-dim)}
.cloze{color:var(--accent);font-weight:600}.photo{max-width:180px;max-height:180px;border-radius:12px;margin:0 auto;object-fit:cover}
.typed{text-align:center;font-size:1.1rem;margin-top:16px}.typed-result.ok{color:var(--rev)}.typed-result.bad{color:var(--danger)}
.answer-bar{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin-top:16px}.answer-bar .show{grid-column:1/-1;padding:16px;font-size:1.05rem}
.grade{border:1px solid var(--border-strong);background:var(--bg-card);color:var(--text);border-radius:var(--radius-sm);padding:12px 4px;font:600 .95rem var(--font);cursor:pointer;display:flex;flex-direction:column;align-items:center;gap:2px;transition:var(--ease)}
.grade:hover{background:var(--bg-hover)}.grade .iv{font-size:.75rem;font-weight:400;color:var(--text-muted)}
.grade.again{border-color:rgba(196,107,107,.5);color:#e09090}.grade.hard{color:#d8b880}.grade.good{border-color:rgba(122,173,138,.5);color:#9cd0ac}.grade.easy{color:#9cb8dc}
.study-done{text-align:center;padding:60px 0}
.mobile-only{display:none}
/* stats */
.stat-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.stat-grid div{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-sm);padding:12px;display:flex;flex-direction:column}
.stat-grid b{font-size:1.6rem;font-family:var(--serif);font-weight:400;color:var(--accent)}.stat-grid span{font-size:.75rem;color:var(--text-muted)}
.heatmap{display:grid;grid-auto-flow:column;grid-template-rows:repeat(7,1fr);gap:3px;overflow-x:auto}.heatmap i{width:12px;height:12px;border-radius:3px;background:var(--bg-card)}
.heatmap .l1{background:rgba(196,165,116,.3)}.heatmap .l2{background:rgba(196,165,116,.5)}.heatmap .l3{background:rgba(196,165,116,.75)}.heatmap .l4{background:var(--accent)}
.forecast{display:flex;gap:8px;height:120px;align-items:flex-end}.forecast div{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:flex-end;height:100%}.forecast span{width:100%;background:var(--accent-soft);border-top:2px solid var(--accent);border-radius:4px 4px 0 0;min-height:2px}
/* modal/toast */
.modal{position:fixed;inset:0;background:rgba(0,0,0,.6);display:none;align-items:center;justify-content:center;z-index:20;padding:16px}.modal.open{display:flex}
.modal-box{background:var(--bg-elevated);border:1px solid var(--border-strong);border-radius:var(--radius);padding:22px;width:100%;max-width:520px;max-height:90dvh;overflow:auto;box-shadow:var(--shadow)}
.toast{position:fixed;left:50%;bottom:90px;transform:translateX(-50%) translateY(20px);background:var(--bg-card);border:1px solid var(--border-strong);padding:10px 18px;border-radius:99px;opacity:0;pointer-events:none;transition:var(--ease);z-index:30}.toast.show{opacity:1;transform:translateX(-50%)}
@media (max-width:700px){
  main{padding:16px 14px 90px}.topbar{padding:10px 14px;backdrop-filter:none;background:var(--bg)}
  .nav{position:fixed;bottom:0;left:0;right:0;margin:0;justify-content:space-around;background:rgba(26,29,39,.97);border-top:1px solid var(--border);padding:6px 4px calc(6px + env(safe-area-inset-bottom))}
  .nav a{flex-direction:column;gap:0;font-size:.68rem;padding:4px 6px}.nav .ni{font-size:1.15rem}
  .hero h1{font-size:2rem}.big-btn{padding:12px 18px}.stat-grid{grid-template-columns:repeat(2,1fr)}
  .desktop-only{display:none}.mobile-only{display:block}.flash{padding:24px 16px;min-height:260px}.study{min-height:calc(100dvh - 190px)}
  .grade{padding:14px 2px}.grade kbd{display:none}.show kbd{display:none}.panel{padding:16px}
}