/* PRIME Study */
:root{
  --bg:#F3F6F5;--surface:#FFFFFF;--surface2:#EBF1EF;--ink:#12201F;--muted:#58706C;--line:#D8E2DF;
  --teal:#0F766E;--teal-ink:#FFFFFF;--teal-soft:#D3EEEA;--amber:#B45309;--amber-soft:#FCEFD6;
  --bad:#B42318;--bad-soft:#FDE7E4;--good:#067647;--good-soft:#DDF5E6;
  --r:14px;--shadow:0 1px 2px rgba(16,32,31,.06),0 4px 16px rgba(16,32,31,.05);
  --sans:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  color-scheme:light;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#0C1414;--surface:#132020;--surface2:#1A2B2A;--ink:#E4EEEC;--muted:#8DA4A0;--line:#243836;
  --teal:#2DD4BF;--teal-ink:#052522;--teal-soft:#10332F;--amber:#FBBF24;--amber-soft:#382808;
  --bad:#F97066;--bad-soft:#3B1512;--good:#47CD89;--good-soft:#0E2F1E;--shadow:none;color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0C1414;--surface:#132020;--surface2:#1A2B2A;--ink:#E4EEEC;--muted:#8DA4A0;--line:#243836;
  --teal:#2DD4BF;--teal-ink:#052522;--teal-soft:#10332F;--amber:#FBBF24;--amber-soft:#382808;
  --bad:#F97066;--bad-soft:#3B1512;--good:#47CD89;--good-soft:#0E2F1E;--shadow:none;color-scheme:dark}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.5 var(--sans);-webkit-font-smoothing:antialiased;overscroll-behavior-y:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
h1,h2,h3{margin:0;line-height:1.25}
h1{font-size:22px;font-weight:700;letter-spacing:-.01em}
h2{font-size:16px;font-weight:600}
h3{font-size:14px;font-weight:600}
p{margin:0}
.wrap{max-width:640px;margin:0 auto;padding:calc(env(safe-area-inset-top) + 10px) 16px calc(env(safe-area-inset-bottom) + 92px)}
.top{display:flex;align-items:center;justify-content:space-between;padding:6px 0 14px}
.brand{display:flex;align-items:center;gap:9px;font-weight:700;font-size:17px;letter-spacing:-.01em}
.brand svg{width:28px;height:28px}
.brand .b1{stroke:var(--line)}.brand .b2{stroke:var(--teal)}.brand .b3{fill:var(--amber)}.brand .b4{stroke:var(--ink)}
.hdr-date{font:500 13px var(--mono);color:var(--muted)}
main{outline:none;display:grid;gap:14px}

.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:16px;box-shadow:var(--shadow);min-width:0}
.card>h2{margin-bottom:10px}
.card-h{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:10px}
.eyebrow{font:600 11.5px var(--mono);text-transform:uppercase;letter-spacing:.08em;color:var(--teal)}
.muted{color:var(--muted)}
.small{font-size:13px}
.mono{font-family:var(--mono)}
.hero{background:linear-gradient(160deg,var(--teal-soft),var(--surface) 70%)}
.hero h1{margin:6px 0 4px}
.hero .actions{margin-top:14px}
.actions{display:flex;flex-wrap:wrap;gap:8px}
.row{display:flex;align-items:center;gap:10px}
.row.between{justify-content:space-between}
.stack{display:grid;gap:10px}
.grid3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}
.grid2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
.tile{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:12px;box-shadow:var(--shadow);min-width:0}
.tile .n{font:600 26px/1.1 var(--mono);letter-spacing:-.02em}
.tile .l{font-size:12px;color:var(--muted);margin-top:2px}
.tile.warn .n{color:var(--amber)}
.tile button{margin-top:8px}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:40px;padding:8px 14px;border-radius:10px;border:1px solid var(--line);background:var(--surface2);font-weight:600;font-size:14px;text-decoration:none;transition:transform .08s}
.btn:active{transform:scale(.97)}
.btn.primary{background:var(--teal);border-color:var(--teal);color:var(--teal-ink)}
.btn.amber{background:var(--amber);border-color:var(--amber);color:var(--surface)}
.btn.ghost{background:transparent}
.btn.danger{color:var(--bad);border-color:var(--bad);background:transparent}
.btn.sm{min-height:32px;padding:4px 10px;font-size:13px;border-radius:8px}
.btn.big{min-height:52px;font-size:16px;padding:12px 20px;width:100%}
.btn.block{width:100%}
.btn:disabled{opacity:.45;cursor:default}
.link{background:none;border:0;color:var(--teal);font-weight:600;padding:0}

label.f{display:grid;gap:4px;font-size:12.5px;font-weight:600;color:var(--muted)}
input[type=text],input[type=number],input[type=date],input[type=search],select,textarea{width:100%;background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:9px 11px;font-size:16px;color:var(--ink);min-height:42px}
textarea{min-height:92px;resize:vertical;line-height:1.45}
textarea.tall{min-height:180px}
input:focus-visible,select:focus-visible,textarea:focus-visible,button:focus-visible{outline:2px solid var(--teal);outline-offset:2px}
.fgrid{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.fgrid .full{grid-column:1/-1}

.bar{height:8px;background:var(--surface2);border-radius:99px;overflow:hidden}
.bar>i{display:block;height:100%;width:0;background:var(--teal);border-radius:99px;transition:width .4s}
.bar.amber>i{background:var(--amber)}
.bar.lg{height:12px}
.pct{font:600 14px var(--mono)}

.exrow{display:grid;gap:6px;padding:12px 0;border-top:1px solid var(--line)}
.exrow:first-of-type{border-top:0;padding-top:2px}
.exrow .row.between h3{font-size:15px}
.chip{display:inline-flex;align-items:center;font:600 11px var(--mono);text-transform:uppercase;letter-spacing:.05em;padding:3px 8px;border-radius:99px;background:var(--surface2);color:var(--muted);white-space:nowrap}
.chip.teal{background:var(--teal-soft);color:var(--teal)}
.chip.amber{background:var(--amber-soft);color:var(--amber)}
.chip.good{background:var(--good-soft);color:var(--good)}
.chip.bad{background:var(--bad-soft);color:var(--bad)}

.week{display:grid;grid-template-columns:repeat(7,1fr);gap:8px;align-items:end;height:120px;padding-top:8px}
.week .col{display:grid;grid-template-rows:1fr auto;height:100%;gap:4px;text-align:center}
.week .stem{display:flex;align-items:flex-end;justify-content:center;background:var(--surface2);border-radius:8px;overflow:hidden}
.week .fill{width:100%;height:0;background:var(--teal);border-radius:8px 8px 0 0;transition:height .4s}
.week .col.today .fill{background:var(--amber)}
.week .d{font:600 11px var(--mono);color:var(--muted)}
.week .col.today .d{color:var(--amber)}

.sess{border-top:1px solid var(--line)}
.sess:first-of-type{border-top:0}
.sess summary{list-style:none;cursor:pointer;padding:10px 0;display:flex;justify-content:space-between;gap:10px;align-items:center}
.sess summary::-webkit-details-marker{display:none}
.sess .t{font-weight:600;font-size:14px}
.sess .notes{display:grid;gap:8px;padding:0 0 12px;font-size:14px}
.sess .notes b{display:block;font:600 11px var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--teal)}
.pre{white-space:pre-wrap;overflow-wrap:anywhere}
.empty{color:var(--muted);font-size:14px;padding:6px 0}

details.fold>summary{cursor:pointer;font-weight:600;list-style:none;display:flex;align-items:center;justify-content:space-between}
details.fold>summary::-webkit-details-marker{display:none}
details.fold>summary::after{content:"+";font:600 18px var(--mono);color:var(--muted)}
details.fold[open]>summary::after{content:"−"}
details.fold[open]>summary{margin-bottom:12px}

/* flashcards */
.flash{min-height:220px;display:grid;align-content:center;gap:14px;text-align:center;padding:24px 18px}
.flash .front{font-size:19px;font-weight:600;line-height:1.4}
.flash .back{font-size:16px;border-top:1px dashed var(--line);padding-top:14px;text-align:left}
.grades{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}
.grades .btn{flex-direction:column;gap:0;min-height:58px;padding:6px}
.grades .btn small{font:500 11px var(--mono);opacity:.8}
.g0{color:var(--bad)}.g3{color:var(--good)}
.clist{display:grid}
.citem{display:grid;grid-template-columns:1fr auto;gap:8px;padding:10px 0;border-top:1px solid var(--line);align-items:start}
.citem:first-child{border-top:0}
.citem .q{font-weight:600;font-size:14px}
.citem .a{font-size:13px;color:var(--muted);display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}

/* quiz */
.qtext{font-size:17px;font-weight:600;line-height:1.45}
.opts{display:grid;gap:8px;margin-top:14px}
.opt{text-align:left;padding:12px 14px;border-radius:12px;border:1px solid var(--line);background:var(--surface);font-size:15px;display:grid;grid-template-columns:26px 1fr;gap:8px;align-items:start}
.opt .k{font:600 13px var(--mono);color:var(--muted);padding-top:1px}
.opt.sel{border-color:var(--teal);background:var(--teal-soft)}
.opt.right{border-color:var(--good);background:var(--good-soft)}
.opt.wrong{border-color:var(--bad);background:var(--bad-soft)}
.explain{margin-top:14px;padding:12px 14px;border-radius:12px;background:var(--surface2);font-size:14px}
.dtable{display:grid;gap:10px}
.drow{display:grid;grid-template-columns:1fr auto;gap:4px 10px;align-items:center;font-size:13.5px}
.drow .bar{grid-column:1/-1}

/* tabs */
.tabs{position:fixed;left:0;right:0;bottom:0;z-index:20;display:grid;grid-template-columns:repeat(4,1fr);background:color-mix(in srgb,var(--surface) 92%,transparent);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-top:1px solid var(--line);padding:6px max(8px,env(safe-area-inset-left)) calc(env(safe-area-inset-bottom) + 6px)}
.tabs button{background:none;border:0;display:grid;justify-items:center;gap:2px;font-size:11.5px;font-weight:600;color:var(--muted);padding:6px 0;border-radius:10px}
.tabs svg{width:24px;height:24px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.tabs button[aria-current="page"]{color:var(--teal)}

/* PRIME player */
.player{position:fixed;inset:0;z-index:40;background:var(--bg);overflow-y:auto;-webkit-overflow-scrolling:touch}
.player[hidden]{display:none}
.pl-wrap{max-width:640px;margin:0 auto;padding:calc(env(safe-area-inset-top) + 10px) 16px calc(env(safe-area-inset-bottom) + 100px);display:grid;gap:14px}
.pl-top{display:flex;align-items:center;justify-content:space-between;gap:10px}
.clock{font:600 20px var(--mono);letter-spacing:-.02em}
.clock.paused{color:var(--amber)}
.steps{display:grid;grid-template-columns:repeat(5,1fr);gap:6px}
.steps button{border:1px solid var(--line);background:var(--surface);border-radius:10px;padding:6px 2px;display:grid;justify-items:center;gap:0;color:var(--muted)}
.steps b{font:700 18px var(--mono)}
.steps span{font-size:10.5px;font-weight:600}
.steps button.on{background:var(--teal);border-color:var(--teal);color:var(--teal-ink)}
.steps button.done{color:var(--teal);border-color:var(--teal)}
.pomo{display:grid;justify-items:center;gap:10px;text-align:center;padding:18px 16px}
.pomo .big{font:600 56px/1 var(--mono);letter-spacing:-.03em}
.pomo .mode{font:600 12px var(--mono);text-transform:uppercase;letter-spacing:.1em;color:var(--teal)}
.pomo.brk .mode,.pomo.brk .big{color:var(--amber)}
.tip{font-size:13.5px;color:var(--muted);background:var(--surface2);border-radius:10px;padding:10px 12px}
.tip b{color:var(--ink)}
.pl-foot{position:fixed;left:0;right:0;bottom:0;z-index:41;background:color-mix(in srgb,var(--surface) 94%,transparent);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-top:1px solid var(--line);padding:10px 16px calc(env(safe-area-inset-bottom) + 10px)}
.pl-foot .in{max-width:640px;margin:0 auto;display:grid;grid-template-columns:1fr 2fr;gap:10px}
.cuerow{display:grid;grid-template-columns:1fr;gap:6px;padding:10px 0;border-top:1px solid var(--line)}
.cuerow:first-child{border-top:0}
.seg{display:inline-grid;grid-auto-flow:column;background:var(--surface2);border-radius:10px;padding:3px;gap:3px}
.seg button{border:0;background:transparent;padding:6px 12px;border-radius:8px;font-weight:600;font-size:13px;color:var(--muted)}
.seg button.on{background:var(--surface);color:var(--ink);box-shadow:var(--shadow)}
.conf{display:flex;gap:6px}
.conf button{width:42px;height:42px;border-radius:10px;border:1px solid var(--line);background:var(--surface);font:600 15px var(--mono)}
.conf button.on{background:var(--teal);color:var(--teal-ink);border-color:var(--teal)}

/* modal + toast */
.modal{position:fixed;inset:0;z-index:60;background:rgba(5,15,14,.55);display:grid;align-items:end;justify-items:center;padding:16px}
.modal[hidden]{display:none}
.modal .sheet{width:100%;max-width:560px;background:var(--surface);border-radius:18px;padding:18px;display:grid;gap:12px;max-height:88vh;overflow:auto;margin-bottom:env(safe-area-inset-bottom)}
.toast{position:fixed;left:50%;bottom:calc(env(safe-area-inset-bottom) + 84px);transform:translate(-50%,20px);background:var(--ink);color:var(--bg);padding:10px 16px;border-radius:12px;font-weight:600;font-size:14px;opacity:0;pointer-events:none;transition:.25s;z-index:80;max-width:90vw;text-align:center}
.toast.show{opacity:1;transform:translate(-50%,0)}

/* splash */
.splash{position:fixed;inset:0;z-index:100;background:#0C1414;display:grid;place-content:center;justify-items:center;gap:10px;transition:opacity .45s}
.splash.out{opacity:0;pointer-events:none}
.splash .logo{width:120px;height:120px}
.splash .arc{stroke-dasharray:210;stroke-dashoffset:210;animation:draw 1s ease-out forwards}
.splash .word{font:700 26px var(--sans);color:#E4EEEC;letter-spacing:-.01em;margin-top:8px}
.splash .tag{font:500 11px var(--mono);color:#2DD4BF;letter-spacing:.06em}
@keyframes draw{to{stroke-dashoffset:0}}
.noscript{padding:24px;text-align:center}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}.splash .arc{stroke-dashoffset:0}}
@media (max-width:380px){.grid3{grid-template-columns:1fr 1fr}.fgrid{grid-template-columns:1fr}.pomo .big{font-size:46px}}