/* A+ Study: dark, Apple-style design. */
:root {
  --bg: #000;
  --bg2: #1c1c1e;
  --bg3: #2c2c2e;
  --bg4: #3a3a3c;
  --sep: rgba(84, 84, 88, .55);
  --label: #fff;
  --label2: rgba(235, 235, 245, .6);
  --label3: rgba(235, 235, 245, .3);
  --blue: #0a84ff;
  --blue-soft: #64b5ff;
  --green: #30d158;
  --orange: #ff9f0a;
  --red: #ff453a;
  --pink: #ff375f;
  --purple: #bf5af2;
  --teal: #64d2ff;
  --yellow: #ffd60a;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", "Helvetica Neue", Inter, system-ui, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --safe-b: env(safe-area-inset-bottom, 0px);
  --safe-t: env(safe-area-inset-top, 0px);
  color-scheme: dark;
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
[hidden] { display: none !important; }
html { background: var(--bg); -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--label);
  font-family: var(--font); font-size: 17px; line-height: 1.35;
  -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale;
}
button, select, input { font: inherit; color: inherit; }
button { cursor: pointer; }
button:disabled { cursor: default; }
a { color: var(--blue); }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 2px; }
h1, h2, h3, p { margin: 0; }
strong { font-weight: 600; color: var(--label); }
code { font-family: var(--mono); background: var(--bg3); padding: 1px 6px; border-radius: 6px; font-size: .88em; }
mark { background: rgba(255, 214, 10, .35); color: var(--label); border-radius: 3px; padding: 0 1px; }

/* ---------- layout ---------- */
#app { min-height: 100vh; min-height: 100dvh; }
#main { padding-bottom: calc(96px + var(--safe-b)); }
.page { max-width: 720px; margin: 0 auto; padding: 18px max(16px, env(safe-area-inset-right, 0px)) 24px max(16px, env(safe-area-inset-left, 0px)); }

#tabbar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 20;
  display: flex; padding: 6px max(4px, env(safe-area-inset-right, 0px)) calc(6px + var(--safe-b)) max(4px, env(safe-area-inset-left, 0px));
  background: rgba(28, 28, 30, .78);
  -webkit-backdrop-filter: saturate(180%) blur(24px); backdrop-filter: saturate(180%) blur(24px);
  border-top: .5px solid var(--sep);
}
.nav-item {
  flex: 1; display: flex; flex-direction: column; align-items: center; gap: 2px;
  padding: 4px 0; color: #8e8e93; text-decoration: none; font-size: 10px; font-weight: 500; border-radius: 10px;
}
.nav-item .ic { width: 25px; height: 25px; }
.nav-item.on { color: var(--blue); }

#sidebar { display: none; }
@media (min-width: 900px) {
  #tabbar { display: none; }
  #main { margin-left: 250px; padding-bottom: 40px; }
  #sidebar {
    display: flex; flex-direction: column; position: fixed; inset: 0 auto 0 0; width: 250px; z-index: 10;
    padding: 24px 12px; background: rgba(28, 28, 30, .72);
    -webkit-backdrop-filter: saturate(180%) blur(28px); backdrop-filter: saturate(180%) blur(28px);
    border-right: .5px solid var(--sep);
  }
  .brand { display: flex; align-items: center; gap: 10px; padding: 0 10px 18px; font-size: 20px; font-weight: 700; }
  .brand-mark {
    width: 34px; height: 34px; border-radius: 9px; display: grid; place-items: center; font-size: 15px;
    background: linear-gradient(135deg, #5ac8fa, #0a84ff); color: #fff;
  }
  #sidebar-nav { display: flex; flex-direction: column; gap: 2px; }
  #sidebar .nav-item { flex-direction: row; gap: 12px; padding: 9px 12px; font-size: 15px; color: var(--label); }
  #sidebar .nav-item .ic { width: 20px; height: 20px; }
  #sidebar .nav-item:hover { background: rgba(255, 255, 255, .06); }
  #sidebar .nav-item.on { background: rgba(10, 132, 255, .22); color: var(--blue-soft); }
  .side-foot { margin-top: auto; padding: 0 10px; font-size: 12px; color: var(--label3); line-height: 1.5; }
  .page { padding-top: 40px; }
}

/* ---------- type ---------- */
h1.large { font-size: 34px; line-height: 1.12; font-weight: 700; letter-spacing: .37px; margin: 2px 0 8px; }
.eyebrow { font-size: 13px; font-weight: 600; text-transform: uppercase; letter-spacing: .6px; color: var(--label2); margin-top: 6px; }
.section-title { font-size: 22px; font-weight: 700; letter-spacing: .3px; margin: 28px 0 8px; }
.sub { font-size: 15px; font-weight: 600; margin: 14px 0 4px; }
.muted { color: var(--label2); }
.small { font-size: 14px; }
.center { text-align: center; }
.dim { color: var(--label3); }
.dimmer { color: var(--label2); font-size: .72em; font-weight: 500; }
.warn-text { color: var(--orange); font-size: 15px; margin: 10px 0; }
.ic { width: 20px; height: 20px; flex: none; }
.ic.dim { width: 16px; height: 16px; }
.c-red { color: var(--red); } .c-orange { color: var(--orange); } .c-green { color: var(--green); } .c-blue { color: var(--blue); } .c-yellow { color: var(--yellow); }

/* ---------- surfaces ---------- */
.card { background: var(--bg2); border-radius: 20px; padding: 16px; margin: 12px 0; }
.card.empty { text-align: center; color: var(--label2); display: flex; flex-direction: column; align-items: center; gap: 12px; }
.list { background: var(--bg2); border-radius: 14px; overflow: hidden; margin: 8px 0 14px; }
.list.flat { background: transparent; }
.li {
  position: relative; display: flex; align-items: center; gap: 12px; width: 100%;
  padding: 12px 16px; min-height: 46px; color: inherit; text-decoration: none; text-align: left;
  background: none; border: 0; border-radius: 0;
}
.li + .li::before { content: ""; position: absolute; top: 0; left: 16px; right: 0; height: .5px; background: var(--sep); }
a.li:active, button.li:active, label.li:active { background: var(--bg3); }
@media (hover: hover) { a.li:hover, button.li:hover, label.li:hover { background: rgba(255, 255, 255, .04); } }
.li-body { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 2px; }
.li-body b { font-weight: 500; font-size: 17px; overflow-wrap: anywhere; }
.li-body small, small { font-size: 13px; color: var(--label2); }
.li-ic { width: 32px; height: 32px; border-radius: 8px; display: grid; place-items: center; flex: none; color: #fff; }
.li-ic .ic { width: 18px; height: 18px; }
.li-ic.orange { background: var(--orange); } .li-ic.blue { background: var(--blue); } .li-ic.red { background: var(--red); }
.li-ic.green { background: var(--green); } .li-ic.purple { background: var(--purple); }
.stack-li { flex-direction: column; align-items: stretch; gap: 10px; }
.stack-li > b { font-weight: 600; font-size: 15px; }
.btn-li { cursor: pointer; }
.danger .li-body b { color: var(--red); }
.num { width: 30px; height: 30px; border-radius: 8px; background: var(--bg3); display: grid; place-items: center; font-size: 14px; font-weight: 700; color: var(--label2); flex: none; }
.snip { font-size: 15px; color: var(--label); overflow-wrap: anywhere; }
.dot { width: 10px; height: 10px; border-radius: 50%; background: var(--bg4); flex: none; }
.dot.good { background: var(--green); } .dot.ok { background: var(--teal); } .dot.warn { background: var(--orange); } .dot.bad { background: var(--red); }

/* ---------- controls ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 50px; padding: 0 20px; border: 0; border-radius: 14px; font-size: 17px; font-weight: 600;
  text-decoration: none; cursor: pointer; transition: transform .12s, opacity .2s, background .2s;
}
.btn:active { transform: scale(.97); }
.btn.primary { background: var(--blue); color: #fff; }
.btn.tinted { background: rgba(10, 132, 255, .16); color: var(--blue-soft); }
.btn.wide { width: 100%; margin-top: 12px; }
.btn:disabled { opacity: .35; }
.row-btns { display: flex; gap: 10px; margin: 12px 0; }
.row-btns .btn { flex: 1; padding: 0 10px; height: 46px; font-size: 15px; }
.link-btn { display: inline-flex; align-items: center; gap: 8px; background: none; border: 0; padding: 10px 0; color: var(--blue); font-size: 15px; text-decoration: none; }
a.back { display: inline-flex; align-items: center; color: var(--blue); text-decoration: none; margin-bottom: 4px; }
a.back .ic { width: 22px; height: 22px; margin-left: -6px; }
.icon-btn { width: 36px; height: 36px; border-radius: 50%; border: 0; background: var(--bg2); display: grid; place-items: center; color: var(--label2); flex: none; }
.icon-btn .ic { width: 18px; height: 18px; }

.seg { display: flex; background: rgba(118, 118, 128, .24); border-radius: 9px; padding: 2px; gap: 2px; width: 100%; }
.seg button { flex: 1; border: 0; background: none; padding: 7px 6px; border-radius: 7px; font-size: 13px; font-weight: 600; color: var(--label); white-space: nowrap; transition: background .2s; }
.seg button.on { background: #636366; box-shadow: 0 2px 6px rgba(0, 0, 0, .35); }

.sel {
  appearance: none; -webkit-appearance: none; width: 100%; border: 0; border-radius: 10px;
  padding: 11px 34px 11px 12px; font-size: 16px; color: var(--label); background-color: var(--bg3);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' fill='none' stroke='%238e8e93' stroke-width='2' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 12px center;
}
.sel option, .sel optgroup { background: #2c2c2e; color: #fff; }
.sel.sm { width: auto; min-width: 84px; padding: 8px 32px 8px 12px; font-size: 15px; }
.sel.wide-sel { max-width: 56%; text-overflow: ellipsis; }
.switch { appearance: none; -webkit-appearance: none; width: 51px; height: 31px; border-radius: 16px; background: #39393d; position: relative; flex: none; transition: background .2s; margin: 0; }
.switch::after { content: ""; position: absolute; top: 2px; left: 2px; width: 27px; height: 27px; border-radius: 50%; background: #fff; box-shadow: 0 2px 4px rgba(0, 0, 0, .3); transition: transform .2s; }
.switch:checked { background: var(--green); }
.switch:checked::after { transform: translateX(20px); }

.search { display: flex; align-items: center; gap: 8px; background: rgba(118, 118, 128, .24); border-radius: 12px; padding: 0 12px; height: 40px; margin: 8px 0 14px; color: var(--label2); }
.search input { flex: 1; min-width: 0; background: none; border: 0; outline: 0; color: var(--label); font-size: 17px; }
.search input::placeholder { color: var(--label2); }

.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 8px 0; }
.chip { display: inline-flex; align-items: center; padding: 4px 10px; border-radius: 999px; background: var(--bg3); color: var(--label2); font-size: 12px; font-weight: 600; border: 0; }
.chip.toggle { font-size: 14px; padding: 8px 14px; }
.chip.toggle.on { background: rgba(10, 132, 255, .22); color: var(--blue-soft); }
.chip.good { background: rgba(48, 209, 88, .16); color: var(--green); }
.chip.ok { background: rgba(100, 210, 255, .16); color: var(--teal); }
.chip.warn { background: rgba(255, 159, 10, .16); color: var(--orange); }
.chip.bad { background: rgba(255, 69, 58, .16); color: var(--red); }
.chip.kind-recall { background: rgba(100, 210, 255, .16); color: var(--teal); }
.chip.kind-compare { background: rgba(191, 90, 242, .18); color: #d29bff; }
.chip.kind-scenario { background: rgba(255, 159, 10, .16); color: var(--orange); }
.chip.kind-pbq { background: rgba(255, 55, 95, .16); color: #ff7a93; }
.tag { font-size: 12px; font-weight: 600; padding: 3px 8px; border-radius: 999px; background: var(--bg3); color: var(--label2); flex: none; }
.tag.good { color: var(--green); } .tag.ok { color: var(--teal); } .tag.warn { color: var(--orange); } .tag.bad { color: var(--red); }
.mini { border: 0; border-radius: 999px; padding: 6px 12px; background: rgba(10, 132, 255, .16); color: var(--blue-soft); font-size: 13px; font-weight: 600; flex: none; }
.score { font-weight: 700; font-size: 18px; font-variant-numeric: tabular-nums; }
.score.good { color: var(--green); } .score.ok { color: var(--orange); } .score.bad { color: var(--red); }

.progress { flex: 1; height: 6px; border-radius: 3px; background: var(--bg3); overflow: hidden; }
.progress i { display: block; height: 100%; background: var(--blue); border-radius: 3px; transition: width .3s; }
.progress.thin { height: 4px; margin: 6px 0 4px; }
.meter { display: block; height: 5px; background: var(--bg3); border-radius: 3px; margin-top: 6px; overflow: hidden; }
.meter i { display: block; height: 100%; background: var(--bg4); border-radius: 3px; transition: width .4s; }
.meter i.good { background: var(--green); } .meter i.ok { background: var(--teal); } .meter i.warn { background: var(--orange); } .meter i.bad { background: var(--red); }

/* ---------- stats, rings, charts ---------- */
.stat-row { display: flex; gap: 10px; margin: 14px 0; }
.stat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin: 14px 0; }
.stat { flex: 1; background: var(--bg2); border-radius: 16px; padding: 14px 6px; text-align: center; display: flex; flex-direction: column; gap: 2px; }
.stat b { font-size: 26px; font-weight: 700; font-variant-numeric: tabular-nums; }
.stat span { font-size: 12px; color: var(--label2); }

.hero { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 20px; background: linear-gradient(150deg, #1c2a45, #1c1c1e 70%); }
.hero-main { display: flex; align-items: center; gap: 14px; }
.hero-num { font-size: 68px; line-height: 1; font-weight: 700; letter-spacing: -1px; font-variant-numeric: tabular-nums; }
.hero-title { font-size: 20px; font-weight: 600; }

.ring { position: relative; width: 92px; height: 92px; flex: none; }
.ring svg { width: 100%; height: 100%; }
.ring-bg { fill: none; stroke: var(--bg4); stroke-width: 10; opacity: .6; }
.ring-fg { fill: none; stroke: var(--pink); stroke-width: 10; stroke-linecap: round; transition: stroke-dasharray .6s cubic-bezier(.2, .8, .2, 1); }
.ring-fg.good { stroke: var(--green); } .ring-fg.ok { stroke: var(--orange); } .ring-fg.bad { stroke: var(--red); }
.ring-txt { position: absolute; inset: 0; display: grid; place-content: center; text-align: center; }
.ring-txt b { font-size: 19px; font-variant-numeric: tabular-nums; }
.ring-txt span { font-size: 11px; color: var(--label2); }
.ring.big { width: 170px; height: 170px; margin: 14px auto; }
.ring.big .ring-txt b { font-size: 38px; }
.ring.big .ring-txt span { font-size: 14px; }

.bars { display: flex; align-items: flex-end; gap: 10px; height: 150px; }
.bar-col { flex: 1; height: 100%; display: flex; flex-direction: column; justify-content: flex-end; align-items: center; gap: 6px; font-size: 11px; color: var(--label2); min-width: 0; }
.bar { width: 100%; max-width: 44px; border-radius: 8px 8px 4px 4px; background: var(--blue); display: flex; justify-content: center; padding-top: 4px; overflow: hidden; }
.bar.good { background: var(--green); } .bar.ok { background: var(--orange); } .bar.bad { background: var(--red); }
.bar i { font-style: normal; font-weight: 700; font-size: 11px; color: rgba(0, 0, 0, .75); }

.stack { display: flex; height: 12px; border-radius: 6px; overflow: hidden; background: var(--bg3); }
.stack i { display: block; height: 100%; }
.mature { background: var(--green); } .young { background: var(--teal); } .learning { background: var(--orange); }
.legend { display: flex; flex-wrap: wrap; gap: 6px 14px; font-size: 13px; color: var(--label2); margin: 12px 0 6px; }
.legend span { display: inline-flex; align-items: center; gap: 6px; }
.legend i { width: 9px; height: 9px; border-radius: 50%; display: inline-block; }
.legend i.new { background: var(--bg4); }
.calib { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; text-align: center; margin-bottom: 10px; }
.calib b { display: block; font-size: 26px; }
.calib span { display: block; font-size: 12px; color: var(--label2); }
.heat { display: grid; grid-template-columns: repeat(14, 1fr); gap: 5px; }
.hm { aspect-ratio: 1; border-radius: 5px; background: var(--bg3); display: block; }
.hm.l1 { background: rgba(48, 209, 88, .3); } .hm.l2 { background: rgba(48, 209, 88, .55); }
.hm.l3 { background: rgba(48, 209, 88, .8); } .hm.l4 { background: var(--green); }

.tiles { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px; }
.tile { background: var(--bg2); border-radius: 18px; padding: 16px; text-decoration: none; color: var(--label); display: flex; flex-direction: column; gap: 4px; }
.tile .ic { width: 26px; height: 26px; color: var(--blue); margin-bottom: 6px; }
.tile b { font-size: 16px; }
.tile small { line-height: 1.3; }
.tile:active { background: var(--bg3); }

/* ---------- notes ---------- */
.five summary { font-weight: 600; cursor: pointer; }
.five ol { margin: 10px 0 0; padding-left: 22px; line-height: 1.45; }
.five li { margin: 6px 0; }
.prose { margin-top: 8px; }
.prose h3 { font-size: 21px; font-weight: 700; margin: 28px 0 8px; letter-spacing: .2px; }
.bul { padding-left: 20px; margin: 6px 0; color: rgba(235, 235, 245, .86); }
.bul li { margin: 7px 0; line-height: 1.45; }
.tbl-wrap { overflow-x: auto; border-radius: 12px; border: .5px solid var(--sep); background: var(--bg2); margin: 10px 0; -webkit-overflow-scrolling: touch; }
table { border-collapse: collapse; width: 100%; min-width: 440px; font-size: 14px; }
th { text-align: left; padding: 10px 12px; font-size: 13px; font-weight: 600; color: var(--label2); background: var(--bg3); }
td { padding: 10px 12px; border-top: .5px solid var(--sep); vertical-align: top; line-height: 1.4; color: rgba(235, 235, 245, .86); }
td.first { color: var(--label); font-weight: 500; }
.callout { margin: 14px 0; padding: 12px 14px; border-radius: 12px; font-size: 15px; line-height: 1.45; background: rgba(255, 159, 10, .1); border-left: 4px solid var(--orange); }
.callout.tip { background: rgba(48, 209, 88, .09); border-left-color: var(--green); }
.pager { display: flex; justify-content: space-between; margin-top: 28px; }
.pager .btn { height: 44px; font-size: 15px; }

/* ---------- flashcards ---------- */
.topbar { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.count { font-size: 13px; color: var(--label2); font-variant-numeric: tabular-nums; min-width: 44px; text-align: right; }
.flip { perspective: 1400px; height: min(52vh, 400px); min-height: 280px; margin: 8px 0 16px; cursor: pointer; outline: none; }
.flip-in { position: relative; width: 100%; height: 100%; transform-style: preserve-3d; transition: transform .55s cubic-bezier(.2, .8, .2, 1); }
.flip.on .flip-in { transform: rotateY(180deg); }
.face {
  position: absolute; inset: 0; -webkit-backface-visibility: hidden; backface-visibility: hidden;
  background: var(--bg2); border: .5px solid rgba(255, 255, 255, .07); border-radius: 26px; padding: 20px 20px 40px;
  display: flex; flex-direction: column; align-items: center; text-align: center; gap: 12px; overflow: auto;
  box-shadow: 0 10px 40px rgba(0, 0, 0, .5);
}
.face.back { transform: rotateY(180deg); background: linear-gradient(160deg, #1b2c47, #1c1c1e 80%); }
.ftxt { margin: auto 0; font-size: 25px; font-weight: 600; line-height: 1.3; letter-spacing: .2px; }
.face.back.long .ftxt { font-size: 19px; font-weight: 500; line-height: 1.4; }
.hint { position: absolute; bottom: 14px; left: 0; right: 0; font-size: 13px; color: var(--label3); }
.hint.dimmer { color: var(--label3); font-size: 12px; padding: 0 20px; }
.ldot { display: inline-block; width: 10px; height: 10px; border-radius: 50%; background: #636366; flex: none; }
.ldot.red { background: var(--red); } .ldot.yellow { background: var(--yellow); } .ldot.green { background: var(--green); }
.face > .ldot { position: absolute; top: 18px; right: 18px; width: 12px; height: 12px; }
.flip { touch-action: none; will-change: transform; }
.flip.snap { transition: transform .2s; }
.flip[data-sw] .face { box-shadow: 0 0 0 3px #8e8e93, 0 10px 40px rgba(0, 0, 0, .5); }
.flip[data-sw=red] .face { box-shadow: 0 0 0 3px var(--red), 0 10px 40px rgba(0, 0, 0, .5); }
.flip[data-sw=yellow] .face { box-shadow: 0 0 0 3px var(--yellow), 0 10px 40px rgba(0, 0, 0, .5); }
.flip[data-sw=green] .face { box-shadow: 0 0 0 3px var(--green), 0 10px 40px rgba(0, 0, 0, .5); }
.lights { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; opacity: .35; pointer-events: none; transition: opacity .25s; }
.lights.show { opacity: 1; pointer-events: auto; }
.lbtn { border: 0; border-radius: 18px; padding: 14px 4px 12px; min-height: 88px; display: flex; flex-direction: column; align-items: center; gap: 8px; background: var(--t); color: var(--label); }
.lbtn b { font-size: 14px; font-weight: 600; }
.lbtn .lamp { width: 34px; height: 34px; border-radius: 50%; background: var(--c); box-shadow: 0 0 18px var(--g); }
.lbtn:active { transform: scale(.96); }
.lbtn.red { --c: var(--red); --g: rgba(255, 69, 58, .45); --t: rgba(255, 69, 58, .14); }
.lbtn.yellow { --c: var(--yellow); --g: rgba(255, 214, 10, .4); --t: rgba(255, 214, 10, .13); }
.lbtn.green { --c: var(--green); --g: rgba(48, 209, 88, .4); --t: rgba(48, 209, 88, .14); }
.cnav { display: flex; gap: 8px; margin-top: 12px; }
.cn { flex: 1; height: 42px; border: 0; border-radius: 12px; background: var(--bg2); color: var(--label2); font-size: 14px; font-weight: 600; display: inline-flex; align-items: center; justify-content: center; gap: 6px; }
.cn.next { background: var(--blue); color: #fff; }
.cn .ic { width: 16px; height: 16px; }
.cn:disabled { opacity: .35; }
.cn:active { transform: scale(.96); }
.lbar { display: flex; height: 12px; border-radius: 6px; overflow: hidden; background: var(--bg3); margin-bottom: 12px; }
.lbar i { display: block; height: 100%; }
.lbar i.red { background: var(--red); } .lbar i.yellow { background: var(--yellow); } .lbar i.green { background: var(--green); } .lbar i.new { background: #636366; }
.lchips { display: flex; flex-wrap: wrap; gap: 8px; }
.lchip { border: 0; border-radius: 999px; padding: 8px 12px; background: var(--bg3); color: var(--label); font-size: 14px; font-weight: 600; display: inline-flex; align-items: center; gap: 7px; }
.lchip b { color: var(--label2); font-variant-numeric: tabular-nums; }
.lchip.on { background: rgba(10, 132, 255, .22); color: var(--blue-soft); }
.swipehint { display: none; margin-top: 10px; }
@media (hover: none) { .swipehint { display: block; } }
.mark { margin: 16px 0 4px; display: grid; gap: 8px; }
.mark > b { font-size: 15px; } .mark small { color: var(--label2); font-weight: 400; }
.markbtns { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.mk { border: 0; border-radius: 14px; height: 48px; font-size: 15px; font-weight: 600; display: inline-flex; align-items: center; justify-content: center; gap: 8px; background: var(--bg2); color: var(--label); }
.mk .ic { width: 18px; height: 18px; stroke-width: 3; }
.mk.know .ic { color: var(--green); } .mk.dont .ic { color: var(--red); }
.mk.know.on { background: rgba(48, 209, 88, .2); box-shadow: inset 0 0 0 2px var(--green); }
.mk.dont.on { background: rgba(255, 69, 58, .2); box-shadow: inset 0 0 0 2px var(--red); }
.mk:active { transform: scale(.97); }
.kbd { margin-top: 14px; }
@media (hover: none) { .kbd { display: none; } }
.done-badge { width: 84px; height: 84px; border-radius: 50%; background: var(--green); display: grid; place-items: center; margin: 28px auto 10px; color: #000; }
.done-badge .ic { width: 44px; height: 44px; stroke-width: 3; }

/* ---------- quiz ---------- */
.qtext { font-size: 22px; font-weight: 600; line-height: 1.3; margin: 14px 0 12px; }
.opts { display: flex; flex-direction: column; gap: 8px; }
.opt {
  display: flex; align-items: flex-start; gap: 12px; width: 100%; text-align: left; padding: 14px;
  background: var(--bg2); border: 1.5px solid transparent; border-radius: 14px; font-size: 16px; line-height: 1.35;
  transition: border-color .15s, background .15s;
}
.opt:disabled { color: var(--label); opacity: 1; }
.opt.sel { border-color: var(--blue); background: rgba(10, 132, 255, .14); }
.opt.right { border-color: var(--green); background: rgba(48, 209, 88, .14); }
.opt.wrong { border-color: var(--red); background: rgba(255, 69, 58, .14); }
.opt.missed { border: 1.5px dashed var(--green); }
.ltr { width: 26px; height: 26px; border-radius: 50%; background: var(--bg3); flex: none; display: grid; place-items: center; font-size: 13px; font-weight: 700; color: var(--label2); }
.ltr.box { border-radius: 7px; }
.ltr .ic { width: 16px; height: 16px; color: var(--blue-soft); stroke-width: 3; }
.opt.sel .ltr { background: var(--blue); color: #fff; }
.opt.sel .ltr .ic { color: #fff; }
.slots { list-style: none; counter-reset: s; padding: 0; margin: 8px 0; }
.slots li { counter-increment: s; display: flex; align-items: center; gap: 10px; margin: 6px 0; }
.slots li::before { content: counter(s); width: 24px; height: 24px; border-radius: 50%; background: var(--bg3); display: grid; place-items: center; font-size: 12px; font-weight: 700; color: var(--label2); flex: none; }
.slot { flex: 1; text-align: left; min-height: 46px; padding: 11px 14px; border-radius: 12px; background: var(--bg2); border: 1.5px solid var(--sep); font-size: 15px; line-height: 1.3; display: block; }
.slot.empty { background: transparent; border-style: dashed; }
.slot.right { border-color: var(--green); background: rgba(48, 209, 88, .14); }
.slot.wrong { border-color: var(--red); background: rgba(255, 69, 58, .14); }
.slot:disabled { color: var(--label); }
.pool { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0; }
.pill { border: 0; padding: 10px 14px; border-radius: 16px; background: rgba(10, 132, 255, .16); color: var(--blue-soft); font-size: 15px; text-align: left; line-height: 1.3; }
.answer-key { background: var(--bg2); border-radius: 12px; padding: 12px 16px; margin: 10px 0; font-size: 14px; }
.answer-key ol { margin: 6px 0 0; padding-left: 20px; }
.matchlist { display: flex; flex-direction: column; gap: 8px; margin-top: 4px; }
.mrow { background: var(--bg2); border-radius: 14px; padding: 12px; display: grid; gap: 8px; border: 1.5px solid transparent; }
.mrow.right { border-color: var(--green); } .mrow.wrong { border-color: var(--red); }
.mp { font-size: 16px; font-weight: 500; }
.fix { color: var(--green); font-size: 13px; }
.conf { margin: 18px 0 4px; display: grid; gap: 8px; }
.conf b { font-size: 15px; }
.feedback { margin: 16px 0 4px; padding: 14px 16px; border-radius: 16px; background: var(--bg2); border-left: 4px solid var(--blue); display: grid; gap: 6px; }
.feedback.good { border-left-color: var(--green); } .feedback.bad { border-left-color: var(--red); }
.fb-head { display: flex; align-items: center; gap: 8px; font-size: 18px; }
.feedback.good .fb-head { color: var(--green); } .feedback.bad .fb-head { color: var(--red); }
.feedback p { font-size: 15px; line-height: 1.45; }
.insight { background: var(--bg2); border-radius: 12px; padding: 12px 14px; margin: 10px 0; font-size: 15px; border-left: 4px solid var(--orange); }
.insight.bad { border-left-color: var(--red); }

/* ---------- export sheet ---------- */
.sheet { position: fixed; inset: 0; z-index: 50; display: flex; align-items: flex-end; justify-content: center; background: rgba(0, 0, 0, .6); -webkit-backdrop-filter: blur(8px); backdrop-filter: blur(8px); }
.sheet-card { width: 100%; max-width: 560px; background: var(--bg2); border-radius: 20px 20px 0 0; padding: 18px max(16px, env(safe-area-inset-right, 0px)) calc(18px + var(--safe-b)) max(16px, env(safe-area-inset-left, 0px)); display: grid; gap: 10px; }
.sheet-card textarea { width: 100%; height: 38vh; resize: none; background: var(--bg3); color: var(--label); border: 0; border-radius: 12px; padding: 12px; font-family: var(--mono); font-size: 12px; line-height: 1.4; }
.sheet-card .row-btns { margin: 0; }
@media (min-width: 700px) { .sheet { align-items: center; } .sheet-card { border-radius: 20px; } }

/* ---------- listen ---------- */
.player { text-align: center; padding: 22px 18px 18px; transition: box-shadow .3s; }
.player.on { box-shadow: 0 0 0 1px rgba(10, 132, 255, .55), 0 10px 50px rgba(10, 132, 255, .25); }
.now { font-size: 24px; font-weight: 600; line-height: 1.3; min-height: 130px; display: flex; align-items: center; justify-content: center; margin: 8px 0 14px; padding: 0 4px; overflow-wrap: anywhere; }
.between { display: flex; justify-content: space-between; }
.transport { display: flex; align-items: center; justify-content: center; gap: 30px; margin-top: 14px; }
.tbtn { width: 58px; height: 58px; border-radius: 50%; border: 0; background: var(--bg3); display: grid; place-items: center; color: var(--label); transition: transform .12s; }
.tbtn:active { transform: scale(.92); }
.tbtn .ic { width: 24px; height: 24px; }
.tbtn.big { width: 86px; height: 86px; background: var(--blue); color: #fff; }
.tbtn.big .ic { width: 38px; height: 38px; }

@media (max-width: 380px) {
  h1.large { font-size: 30px; }
  .hero-num { font-size: 56px; }
  .qtext { font-size: 20px; }
  .ftxt { font-size: 22px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: .01ms !important; animation-duration: .01ms !important; }
}