:root{
  --bg:#F2F6F7; --panel:#FFFFFF; --ink:#0F1B22; --muted:#5B6C76; --line:#D2DCE1; --soft:#E7EEF1; --soft2:#DCE6EA;
  --toward:#C4413C; --away:#2B62C3; --toward-soft:#FBE8E7; --away-soft:#E5EDFB;
  --ok:#2A7A58; --warn:#B8791E; --focus:#2B62C3;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#0B1317; --panel:#121E27; --ink:#E2EBF0; --muted:#94A6B0; --line:#233540; --soft:#16252E; --soft2:#1D303B;
    --toward:#E5675F; --away:#6E9CEC; --toward-soft:#3B1F1E; --away-soft:#1A2A45;
    --ok:#5FC08F; --warn:#DBA84C; --focus:#6E9CEC;
  }
}
:root[data-theme="dark"]{
  --bg:#0B1317; --panel:#121E27; --ink:#E2EBF0; --muted:#94A6B0; --line:#233540; --soft:#16252E; --soft2:#1D303B;
  --toward:#E5675F; --away:#6E9CEC; --toward-soft:#3B1F1E; --away-soft:#1A2A45;
  --ok:#5FC08F; --warn:#DBA84C; --focus:#6E9CEC;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important;animation:none!important}}
body{margin:0;background:var(--bg);color:var(--ink);font-family:"Instrument Sans","Helvetica Neue",Arial,sans-serif;font-size:16px;line-height:1.55;-webkit-font-smoothing:antialiased}
a{color:var(--away)}
:focus-visible{outline:2px solid var(--focus);outline-offset:2px}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
.mono{font-family:"JetBrains Mono",ui-monospace,Menlo,monospace;font-variant-numeric:tabular-nums}
.display{font-family:"Bricolage Grotesque","Helvetica Neue",Arial,sans-serif}
.serif{font-family:"Source Serif 4",Georgia,serif}

/* header */
.bart{height:5px;background:linear-gradient(90deg,var(--away) 0 50%,var(--toward) 50% 100%)}
header.top{display:flex;align-items:center;gap:18px;padding:14px 24px;border-bottom:1px solid var(--line);background:var(--panel);position:sticky;top:0;z-index:5}
header.top .brand{font-family:"Bricolage Grotesque",sans-serif;font-weight:800;font-size:19px;letter-spacing:-.02em;text-decoration:none;color:var(--ink);white-space:nowrap}
header.top .brand span{color:var(--muted);font-weight:400}
header.top nav{display:flex;gap:4px;flex-wrap:wrap}
header.top nav a{text-decoration:none;color:var(--ink);padding:6px 10px;border-radius:4px;font-size:14px;font-weight:500}
header.top nav a.active,header.top nav a:hover{background:var(--soft)}
header.top .search{margin-left:auto;display:flex;align-items:center;gap:6px}
header.top input{font:inherit;font-size:14px;padding:7px 10px;border:1px solid var(--line);border-radius:4px;background:var(--bg);color:var(--ink);width:220px}
.due-pill{font-family:"JetBrains Mono",monospace;font-size:11.5px;background:var(--toward-soft);color:var(--toward);padding:2px 7px;border-radius:10px;margin-left:6px}
@media (max-width:760px){header.top{flex-wrap:wrap}header.top .search{margin-left:0;width:100%}header.top input{width:100%}}

main{max-width:1180px;margin:0 auto;padding:28px 24px 96px}
h1{font-family:"Bricolage Grotesque",sans-serif;font-size:clamp(28px,4vw,42px);font-weight:800;letter-spacing:-.02em;line-height:1.05;margin:0 0 8px;text-wrap:balance}
h2{font-family:"Bricolage Grotesque",sans-serif;font-size:22px;font-weight:700;margin:36px 0 12px;letter-spacing:-.01em}
h3{font-family:"Bricolage Grotesque",sans-serif;font-size:16px;font-weight:600;margin:20px 0 6px}
.eyebrow{font-size:11.5px;letter-spacing:.13em;text-transform:uppercase;color:var(--muted);font-weight:600;margin:0 0 8px}
.lede{font-size:17px;color:var(--muted);max-width:66ch;margin:0 0 22px}
.muted{color:var(--muted)}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}

/* grid (home) */
.gridwrap{overflow-x:auto;border:1px solid var(--line);background:var(--panel);border-radius:6px}
table.grid{border-collapse:collapse;width:100%;min-width:900px}
table.grid th{font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);padding:10px 6px;text-align:center;border-bottom:1px solid var(--line);font-weight:600}
table.grid th:first-child{text-align:left;padding-left:14px}
table.grid td{padding:0;border-bottom:1px solid var(--line);text-align:center}
table.grid td:first-child{text-align:left;padding:0}
table.grid td:first-child a{display:block;padding:9px 14px;text-decoration:none;color:var(--ink);font-weight:600;font-size:14px;white-space:nowrap}
table.grid td:first-child a:hover{background:var(--soft)}
table.grid td a.cell{display:block;padding:9px 6px;text-decoration:none;font-family:"JetBrains Mono",monospace;font-size:12.5px;color:var(--ink)}
table.grid td a.cell:hover{outline:2px solid var(--away);outline-offset:-2px}
table.grid td span.empty{display:block;padding:9px 6px;color:var(--line);font-family:"JetBrains Mono",monospace;font-size:12px}
.c1{background:var(--away-soft)}
.c2{background:color-mix(in srgb,var(--away) 30%,var(--panel))}
.c3{background:color-mix(in srgb,var(--away) 55%,var(--panel));color:#fff!important}
.grid-legend{display:flex;gap:16px;font-size:12.5px;color:var(--muted);margin:10px 0 0;align-items:center}
.grid-legend i{display:inline-block;width:14px;height:14px;vertical-align:-2px;margin-right:5px;border:1px solid var(--line)}

.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:10px;margin:22px 0 30px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:12px 14px}
.stat b{display:block;font-family:"JetBrains Mono",monospace;font-size:24px;font-weight:600;letter-spacing:-.02em}
.stat span{font-size:12.5px;color:var(--muted)}
.stat a{text-decoration:none}

/* card list */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:12px}
.cardtile{background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:14px 16px;text-decoration:none;color:var(--ink);display:flex;flex-direction:column;gap:6px}
.cardtile:hover{border-color:var(--away)}
.cardtile .id{font-family:"JetBrains Mono",monospace;font-size:11.5px;color:var(--muted)}
.cardtile .t{font-family:"Bricolage Grotesque",sans-serif;font-weight:600;font-size:16px;line-height:1.25}
.cardtile .q{font-size:13.5px;color:var(--muted);display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.chips{display:flex;gap:5px;flex-wrap:wrap}
.chip{font-size:11px;letter-spacing:.04em;padding:2px 7px;border-radius:3px;background:var(--soft);color:var(--muted);text-decoration:none;font-weight:600}
.chip.lens{background:var(--away-soft);color:var(--away)}
.chip.delta{background:var(--toward-soft);color:var(--toward)}
.chip.srs{font-family:"JetBrains Mono",monospace;font-weight:400}

/* card page */
.cardpage{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:32px}
@media (max-width:900px){.cardpage{grid-template-columns:1fr}}
.item{background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:18px 20px;margin:0 0 12px}
.item .qq{font-family:"Bricolage Grotesque",sans-serif;font-weight:600;font-size:18px;line-height:1.3;margin:0 0 10px}
.item .aa{font-family:"Source Serif 4",Georgia,serif;font-size:17px;line-height:1.6;max-width:68ch}
.item .aa p{margin:0 0 10px}
.item .reveal{font-size:13.5px;font-weight:600;color:var(--away);padding:8px 12px;border:1px solid var(--line);border-radius:4px;background:var(--bg)}
.item .reveal:hover{background:var(--soft)}
.item .hidden{display:none}
.side{display:flex;flex-direction:column;gap:14px}
.box{background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:14px 16px;font-size:14px}
.box h3{margin:0 0 8px;font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.box ul{margin:0;padding-left:18px}
.box li{margin:3px 0}
.delta{border-left:4px solid var(--toward);background:var(--toward-soft);border-radius:0 6px 6px 0;padding:14px 16px;margin:0 0 12px}
.delta .k{font-size:11px;letter-spacing:.1em;text-transform:uppercase;font-weight:700;color:var(--toward);margin:0 0 4px}
.delta p{margin:0 0 8px;font-size:15px}
.delta .src{font-size:12.5px;color:var(--muted);font-family:"JetBrains Mono",monospace}
.pearl{border-left:4px solid var(--away);background:var(--away-soft);border-radius:0 6px 6px 0;padding:12px 16px;margin:0 0 12px;font-family:"Source Serif 4",serif;font-style:italic;font-size:16px}
.numtable{width:100%;border-collapse:collapse;font-size:13.5px}
.numtable td{padding:5px 0;border-bottom:1px solid var(--line);vertical-align:top}
.numtable td.v{font-family:"JetBrains Mono",monospace;text-align:right;white-space:nowrap;padding-left:10px}
.numtable tr:last-child td{border-bottom:0}
.prevnext{display:flex;justify-content:space-between;margin-top:24px;font-size:14px}
.prevnext a{text-decoration:none}

/* study */
.study{max-width:760px;margin:0 auto}
.studycard{background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:28px 30px;min-height:260px;display:flex;flex-direction:column;gap:16px}
.studycard .qq{font-family:"Bricolage Grotesque",sans-serif;font-weight:600;font-size:22px;line-height:1.3}
.studycard .aa{font-family:"Source Serif 4",serif;font-size:17px;line-height:1.6;border-top:1px dashed var(--line);padding-top:16px}
.rate{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin-top:auto}
.rate button{padding:12px 8px;border:1px solid var(--line);border-radius:6px;background:var(--bg);font-weight:600;font-size:14px}
.rate button small{display:block;font-weight:400;color:var(--muted);font-family:"JetBrains Mono",monospace;font-size:11px;margin-top:2px}
.rate button:hover{background:var(--soft)}
.rate .again{border-color:var(--toward);color:var(--toward)}
.rate .easy{border-color:var(--ok);color:var(--ok)}
.showbtn{padding:14px;border:1px solid var(--away);color:var(--away);border-radius:6px;font-weight:600;margin-top:auto}
.showbtn:hover{background:var(--away-soft)}
.studybar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin:0 0 16px;font-size:13.5px}
.studybar select{font:inherit;font-size:13.5px;padding:6px 8px;border:1px solid var(--line);border-radius:4px;background:var(--panel);color:var(--ink)}
.progress{height:4px;background:var(--soft2);border-radius:2px;overflow:hidden;margin:0 0 14px}
.progress i{display:block;height:100%;background:var(--away)}
.kbd{font-family:"JetBrains Mono",monospace;font-size:11px;border:1px solid var(--line);border-radius:3px;padding:0 5px;color:var(--muted)}

/* numbers */
.numwall{width:100%;border-collapse:collapse;background:var(--panel);border:1px solid var(--line);border-radius:6px;font-size:14px}
.numwall th{font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);text-align:left;padding:10px 12px;border-bottom:1px solid var(--line)}
.numwall td{padding:8px 12px;border-bottom:1px solid var(--line)}
.numwall td.v{font-family:"JetBrains Mono",monospace;white-space:nowrap;font-weight:600}
.numwall td.u{font-family:"JetBrains Mono",monospace;color:var(--muted);white-space:nowrap}
.numwall tr:last-child td{border-bottom:0}
.numwall a{text-decoration:none;font-family:"JetBrains Mono",monospace;font-size:12px}
.drill{background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:28px;max-width:640px;margin:0 auto 24px;text-align:center}
.drill .label{font-family:"Bricolage Grotesque",sans-serif;font-size:22px;font-weight:600;margin:0 0 14px}
.drill .val{font-family:"JetBrains Mono",monospace;font-size:38px;font-weight:600;letter-spacing:-.02em;min-height:56px}
.drill .val.blur{filter:blur(12px);user-select:none}
.drill .ctx{font-size:13px;color:var(--muted);margin-top:8px}
.drill .btns{display:flex;gap:8px;justify-content:center;margin-top:16px}
.btn{padding:9px 14px;border:1px solid var(--line);border-radius:5px;background:var(--bg);font-weight:600;font-size:14px;text-decoration:none;color:var(--ink);display:inline-block}
.btn:hover{background:var(--soft)}
.btn.primary{background:var(--away);border-color:var(--away);color:#fff}
.btn.primary:hover{background:color-mix(in srgb,var(--away) 85%,#000)}

.filters{display:flex;gap:6px;flex-wrap:wrap;margin:0 0 18px}
.filters a{font-size:12.5px;padding:4px 9px;border:1px solid var(--line);border-radius:14px;text-decoration:none;color:var(--ink);background:var(--panel)}
.filters a.on{background:var(--ink);color:var(--bg);border-color:var(--ink)}
mark{background:var(--away-soft);color:inherit;padding:0 1px}
.empty{padding:40px;text-align:center;color:var(--muted);border:1px dashed var(--line);border-radius:6px}
footer{max-width:1180px;margin:0 auto;padding:0 24px 40px;font-size:12.5px;color:var(--muted)}
.deltalist .item{border-left:4px solid var(--toward)}
.numwall td.v,.numwall td.u{width:1%}
.numwall th:nth-child(3){width:38%}
/* account / banner / toast */
.account .acct{font-family:"Bricolage Grotesque",sans-serif;font-size:13.5px;font-weight:600;padding:6px 12px;border:1px solid var(--line);border-radius:4px;text-decoration:none;color:var(--ink);white-space:nowrap}
.account .acct:hover{background:var(--soft)}
.banner{display:flex;align-items:center;gap:12px;justify-content:space-between;background:var(--away-soft);color:var(--ink);padding:10px 24px;font-size:14px;border-bottom:1px solid var(--line)}
.banner .x{font-size:20px;line-height:1;color:var(--muted);padding:0 6px}
button.link{color:var(--away);text-decoration:underline;padding:0;font-size:inherit}
.toast{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);background:var(--ink);color:var(--bg);padding:10px 16px;border-radius:6px;font-size:14px;font-family:"Bricolage Grotesque",sans-serif;box-shadow:0 4px 16px rgba(0,0,0,.2);z-index:20;max-width:90vw}
.banner[hidden],.toast[hidden]{display:none}