:root {
  --bg: #f6f4f0; --panel: #ffffff; --panel-2: #f0ede7; --line: #e2ddd4;
  --ink: #1f2328; --ink-2: #5b6168; --ink-3: #8a9096;
  --accent: #c55a11; --accent-ink: #ffffff; --accent-soft: #fbe9dc;
  --ok: #1f7a4d; --ok-soft: #dcf1e5; --warn: #9a6400; --warn-soft: #fbefd2; --bad: #b3261e; --bad-soft: #fbe0de;
  --shadow: 0 1px 2px rgba(0,0,0,.05), 0 4px 16px rgba(0,0,0,.04);
  --r: 12px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #15171a; --panel: #1d2024; --panel-2: #25292e; --line: #33383e;
    --ink: #e8e6e3; --ink-2: #a9adb2; --ink-3: #7c8187;
    --accent: #e7823f; --accent-ink: #1a0f07; --accent-soft: #3a2616;
    --ok: #5cc98f; --ok-soft: #173325; --warn: #e2b04a; --warn-soft: #362a12; --bad: #f08a82; --bad-soft: #3b1c1a;
    --shadow: none; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #15171a; --panel: #1d2024; --panel-2: #25292e; --line: #33383e;
  --ink: #e8e6e3; --ink-2: #a9adb2; --ink-3: #7c8187;
  --accent: #e7823f; --accent-ink: #1a0f07; --accent-soft: #3a2616;
  --ok: #5cc98f; --ok-soft: #173325; --warn: #e2b04a; --warn-soft: #362a12; --bad: #f08a82; --bad-soft: #3b1c1a;
  --shadow: none; color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body { background: var(--bg); color: var(--ink); font: 15px/1.55 "Segoe UI", system-ui, -apple-system, sans-serif; }
button, input, select { font: inherit; color: inherit; }
h1 { font-size: 1.45rem; margin: 0 0 .25rem; letter-spacing: -.01em; }
h2 { font-size: 1.1rem; margin: 1.4rem 0 .6rem; }
h3 { font-size: 1rem; margin: 0 0 .4rem; }
.muted { color: var(--ink-2); }
.small { font-size: .85rem; }

/* layout */
.shell { display: grid; grid-template-columns: var(--side-w, 280px) 1fr; min-height: 100vh; transition: grid-template-columns .2s; }
.side { background: var(--panel); border-right: 1px solid var(--line); padding: 18px 14px; position: sticky; top: 0; height: 100vh;
  display: flex; flex-direction: column; gap: 16px; overflow-y: auto; }
.brand { display: flex; gap: 10px; align-items: center; }
.brand small { display: block; color: var(--ink-3); font-size: .78rem; }
.brand > div { min-width: 0; }
.brand b, .brand small { display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.logo { width: 36px; height: 36px; border-radius: 9px; background: var(--accent); color: var(--accent-ink); display: grid; place-items: center; font-weight: 700; font-size: .85rem; }
.lesson-pick { font-size: .78rem; color: var(--ink-3); display: grid; gap: 4px; }
.lesson-pick select { padding: 7px 8px; border: 1px solid var(--line); border-radius: 8px; background: var(--panel-2); font-size: .88rem; }
nav { display: grid; gap: 2px; }
nav button { text-align: left; background: none; border: 0; padding: 8px 10px; border-radius: 8px; cursor: pointer; color: var(--ink-2); display: flex; gap: 10px; align-items: center; }
nav button .ico { width: 20px; text-align: center; }
nav button:hover { background: var(--panel-2); color: var(--ink); }
nav button.on { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.nav-sec { font-size: .7rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); padding: 12px 10px 4px; }
.nav-sec:first-child { padding-top: 0; }
/* the selected lesson's pages sit in their own box under the lesson picker */
.lesson-zone { display: grid; gap: 10px; padding: 12px 8px 8px; border: 1px solid var(--line); border-radius: 16px; background: var(--panel-2); }
.lesson-zone .lesson-pick { padding: 0 2px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; font-size: .7rem; }
.lesson-zone { min-width: 0; }
.lesson-zone .lesson-pick select { background: var(--panel); text-transform: none; letter-spacing: 0; width: 100%; min-width: 0; text-overflow: ellipsis; }
.side { overflow-x: hidden; scrollbar-width: thin; }
.lesson-zone nav button:hover { background: var(--panel); }
.theme-btn { margin-top: auto; background: none; border: 1px solid var(--line); border-radius: 8px; padding: 6px 10px; cursor: pointer; color: var(--ink-2); }
main { padding: 28px 32px 60px; max-width: 980px; width: 100%; min-width: 0; }
/* sidebar: « collapses it to icons (Ctrl+B), its right edge is dragged to resize (app.js setupSidebar) */
.side-toggle { position: absolute; top: 4px; right: 4px; width: 24px; height: 24px; border: 0; border-radius: 9px; background: none; color: var(--ink-3); cursor: pointer; display: grid; place-items: center; }
.side-toggle:hover { background: var(--panel-2); color: var(--ink); }
.side-toggle svg { transition: transform .2s; }
.side-resizer { position: fixed; top: 0; left: calc(var(--side-w, 280px) - 3px); width: 7px; height: 100vh; cursor: col-resize; z-index: 30; }
.side-resizer::after { content: ""; position: absolute; left: 3px; top: 0; bottom: 0; width: 2px; background: var(--accent); opacity: 0; transition: opacity .15s; }
.side-resizer:hover::after, .shell.side-drag .side-resizer::after { opacity: .6; }
.shell.side-drag { transition: none; user-select: none; cursor: col-resize; }
@media (min-width: 761px) {
  .shell.side-min { grid-template-columns: 78px 1fr; }
  .side-min .side-resizer { left: 75px; }
  .side-min .side { padding-left: 10px; padding-right: 10px; }
  .side-min .brand { flex-direction: column; }
  .side-min .brand > div, .side-min .mascot-card, .side-min .nav-sec, .side-min .lesson-pick, .side-min .lbl { display: none; }
  .side-min .side-toggle { position: static; }
  .side-min .side-toggle svg { transform: rotate(180deg); }
  .side-min nav button { justify-content: center; padding-left: 0; padding-right: 0; }
  .side-min .lesson-zone { padding: 8px 4px; }
}

@media (max-width: 760px) {
  .shell, .shell.side-min { grid-template-columns: 1fr; }
  .side { position: static; height: auto; border-right: 0; border-bottom: 1px solid var(--line); padding: 12px 16px; gap: 10px; }
  nav { display: flex; overflow-x: auto; gap: 4px; padding-bottom: 4px; }
  nav button { white-space: nowrap; flex: none; }
  .nav-sec { display: none; }
  .lesson-zone { padding: 8px; }
  .theme-btn { display: none; }
  .side-toggle, .side-resizer { display: none; }
  main { padding: 18px 16px 48px; }
}

/* generic parts */
.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--r); padding: 18px 20px; box-shadow: var(--shadow); }
.card + .card { margin-top: 12px; }
.grid { display: grid; gap: 12px; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); }
.row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.spacer { flex: 1; }
.btn { border: 1px solid var(--line); background: var(--panel); border-radius: 9px; padding: 8px 14px; cursor: pointer; display: inline-flex; gap: 6px; align-items: center; line-height: 1.2; }
.btn:hover { background: var(--panel-2); }
.btn:disabled { opacity: .45; cursor: default; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); font-weight: 600; }
.btn.primary:hover { filter: brightness(1.07); }
.btn.ghost { border-color: transparent; background: none; }
.btn.sm { padding: 5px 9px; font-size: .85rem; border-radius: 7px; }
.btn.rec { border-color: var(--bad); color: var(--bad); }
.btn.rec.live { background: var(--bad); color: #fff; animation: pulse 1.2s infinite; }
@keyframes pulse { 50% { opacity: .7; } }
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip { border: 1px solid var(--line); background: var(--panel); border-radius: 999px; padding: 5px 12px; cursor: pointer; font-size: .88rem; }
.chip.on { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); font-weight: 600; }
.field { display: grid; gap: 6px; margin: 14px 0; }
.field > span { font-size: .82rem; color: var(--ink-3); font-weight: 600; text-transform: uppercase; letter-spacing: .04em; }
input[type=text] { width: 100%; border: 1px solid var(--line); background: var(--panel); border-radius: 9px; padding: 10px 12px; font-size: 1.05rem; }
input[type=text]:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
.pill { display: inline-block; padding: 2px 9px; border-radius: 999px; font-size: .8rem; font-weight: 600; }
.pill.ok { background: var(--ok-soft); color: var(--ok); }
.pill.warn { background: var(--warn-soft); color: var(--warn); }
.pill.bad { background: var(--bad-soft); color: var(--bad); }
.pill.dim { background: var(--panel-2); color: var(--ink-3); }
.toast { position: fixed; bottom: 20px; left: 50%; transform: translateX(-50%); background: var(--ink); color: var(--bg); padding: 10px 16px; border-radius: 10px; font-size: .9rem; z-index: 10; max-width: 90vw; }
.notice { background: var(--warn-soft); color: var(--warn); border-radius: 10px; padding: 10px 14px; font-size: .9rem; margin: 10px 0; }

/* dashboard */
.stat { display: flex; flex-direction: column; gap: 4px; }
.stat .big { font-size: 1.7rem; font-weight: 700; letter-spacing: -.02em; }
.mode-card { cursor: pointer; transition: border-color .15s; }
.mode-card:hover { border-color: var(--accent); }
.mode-card .ico { font-size: 1.3rem; }
.bar { height: 6px; background: var(--panel-2); border-radius: 99px; overflow: hidden; margin: 8px 0 4px; }
.bar > i { display: block; height: 100%; background: var(--accent); border-radius: 99px; }

/* runner */
.run-head { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; }
.run-head .bar { flex: 1; margin: 0; }
.prompt { font-size: 1.3rem; font-weight: 600; margin: 4px 0 10px; }
.prompt.vn { font-weight: 500; }
.sub { color: var(--ink-2); font-size: .92rem; }
.words { font-size: 1.12rem; line-height: 1.9; }
.words .w { padding: 1px 3px; border-radius: 4px; }
.words .w.ok { color: var(--ok); }
.words .w.miss { background: var(--bad-soft); color: var(--bad); text-decoration: underline wavy; text-underline-offset: 4px; }
.heard { font-size: .9rem; color: var(--ink-2); margin-top: 6px; }
.heard em { color: var(--ink); }
.feedback { margin-top: 14px; padding: 12px 14px; border-radius: 10px; background: var(--panel-2); }
.feedback.ok { background: var(--ok-soft); }
.feedback.bad { background: var(--bad-soft); }
.answer { font-weight: 600; }
.opts { display: grid; gap: 8px; margin-top: 12px; }
.opt { text-align: left; border: 1px solid var(--line); background: var(--panel); border-radius: 10px; padding: 11px 14px; cursor: pointer; display: flex; gap: 10px; }
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt .k { color: var(--ink-3); font-weight: 600; min-width: 1.1em; }
.opt.right { border-color: var(--ok); background: var(--ok-soft); }
.opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt:disabled { cursor: default; }

/* comprehension: one scene = the player (sticky) + all its questions on one page */
.sp { position: sticky; top: 0; z-index: 5; background: var(--panel); margin: -6px -6px 0; padding: 8px 6px 12px; border-bottom: 1px solid var(--line); }
.sp.solo { margin: 0 0 14px; padding: 12px 16px 16px; border: 1px solid var(--line); border-radius: 16px; box-shadow: 0 6px 18px rgba(20, 60, 60, .08); }
.sp-ctl { gap: 8px; align-items: center; }
.sp-play { min-width: 128px; }
.sp-line, .sp-time { color: var(--ink-3); font-size: .85rem; font-variant-numeric: tabular-nums; }
.sp-bar { position: relative; height: 10px; margin-top: 12px; background: var(--panel-2); border-radius: 99px; cursor: pointer; touch-action: none; }
.sp-bar > i { position: absolute; left: 0; top: 0; bottom: 0; background: var(--accent); border-radius: 99px; pointer-events: none; }
.sp-bar > b { position: absolute; top: 50%; width: 16px; height: 16px; margin: -8px 0 0 -8px; border-radius: 50%; background: var(--panel); border: 3px solid var(--accent); pointer-events: none; }
.sp-ticks span { position: absolute; top: -3px; bottom: -3px; width: 2px; margin-left: -1px; background: var(--line); pointer-events: none; }
.sheet-tip { margin: 10px 0 4px; }
.cq { border: 2px solid transparent; border-radius: 14px; padding: 10px 12px; margin-top: 8px; transition: border-color .15s, background .15s; }
.cq.on { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 5%, transparent); }
.cq.ok { opacity: .8; }
.cq-q { font-weight: 600; display: flex; gap: 10px; align-items: baseline; }
.cq-n { flex: none; width: 26px; height: 26px; border-radius: 50%; display: inline-grid; place-items: center; background: var(--panel-2); font-size: .85rem; }
.cq.on .cq-n { background: var(--accent); color: var(--accent-ink); }
.cq.ok .cq-n { background: var(--ok); color: #fff; }
.cq.bad .cq-n { background: var(--bad); color: #fff; }
.cq .opts { grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); margin-top: 8px; }
.cq .opt { padding: 8px 12px; }
.cq-fb { margin-top: 6px; font-size: .9rem; }
.cq.ok .cq-fb b { color: var(--ok); }
.cq.bad .cq-fb b { color: var(--bad); }
input.blank { display: inline-block; width: auto; min-width: 7ch; font-size: 1.05rem; padding: 3px 8px; margin: 2px 2px; border-radius: 7px; border: 1px solid var(--line); background: var(--panel-2); }
input.blank.right { border-color: var(--ok); background: var(--ok-soft); color: var(--ok); }
input.blank.wrong { border-color: var(--bad); background: var(--bad-soft); color: var(--bad); }
.fill-text { font-size: 1.15rem; line-height: 2.2; }
.kbd { font-family: ui-monospace, Consolas, monospace; font-size: .78rem; border: 1px solid var(--line); border-bottom-width: 2px; padding: 0 5px; border-radius: 5px; color: var(--ink-3); }

/* shadowing list */
.line { display: grid; grid-template-columns: 34px 1fr; gap: 10px; padding: 12px 0; border-top: 1px solid var(--line); }
.line:first-child { border-top: 0; }
.line.active { background: var(--accent-soft); margin: 0 -20px; padding: 12px 20px; }
.who { width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; font-weight: 700; font-size: .82rem; }
.who.A { background: #dbe8f7; color: #1d4f86; } .who.B { background: #e7def5; color: #5a3593; }
:root[data-theme="dark"] .who.A { background: #1d3550; color: #a8c9f0; } :root[data-theme="dark"] .who.B { background: #342552; color: #cdb8f0; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .who.A { background: #1d3550; color: #a8c9f0; } :root:not([data-theme="light"]) .who.B { background: #342552; color: #cdb8f0; } }
.line .en { font-size: 1.05rem; }
.line .en.hidden { filter: blur(6px); user-select: none; }
.line .tr { color: var(--ink-2); font-size: .9rem; font-style: italic; }
.line .ctl { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 6px; align-items: center; }

/* vocab table */
table { width: 100%; border-collapse: collapse; }
td, th { text-align: left; padding: 9px 8px; border-top: 1px solid var(--line); vertical-align: top; }
th { font-size: .78rem; color: var(--ink-3); text-transform: uppercase; letter-spacing: .04em; border-top: 0; }
td .ex { color: var(--ink-2); font-size: .9rem; }
.transcript p { margin: 6px 0; }
.transcript b { color: var(--accent); }

/* listening player */
.listen-bar { position: sticky; top: 0; z-index: 2; background: var(--bg); padding: 8px 0; margin: 6px 0 12px; }

/* insights */
a.btn { text-decoration: none; color: inherit; }
.grid > .card + .card { margin-top: 0; }
.pill { white-space: nowrap; }

/* progress dashboard: one blue sequential ramp for magnitude (dataviz reference palette) */
:root { --seq1: #86b6ef; --seq2: #3987e5; --seq3: #1c5cab; --seq4: #0d366b; --series: #2a78d6; --m-done: #1c5cab; --m-learn: #86b6ef; }
:root[data-theme="dark"] { --seq1: #184f95; --seq2: #256abf; --seq3: #3987e5; --seq4: #86b6ef; --series: #5598e7; --m-done: #5598e7; --m-learn: #1c5cab; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --seq1: #184f95; --seq2: #256abf; --seq3: #3987e5; --seq4: #86b6ef; --series: #5598e7; --m-done: #5598e7; --m-learn: #1c5cab; } }
.grid.two { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); margin-top: 12px; }
.grid.badges { grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); }
.chart h3 { margin-bottom: 2px; }
.plot-wrap { position: relative; }
.plot { width: 100%; overflow-x: auto; }
.plot svg { display: block; }
.plot .ax { font-size: 11px; fill: var(--ink-3); }
.plot .grid { stroke: var(--line); stroke-width: 1; }
.plot .base { stroke: var(--ink-3); stroke-width: 1; }
.plot .cross { stroke: var(--ink-3); stroke-width: 1; stroke-dasharray: 3 3; }
.plot .series-line { fill: none; stroke: var(--series); stroke-width: 2; stroke-linejoin: round; }
.plot .series-dot { fill: var(--series); stroke: var(--panel); stroke-width: 2; }
.plot .series-bar { fill: var(--series); }
.hm0 { fill: var(--panel-2); } .hm1 { fill: var(--seq1); } .hm2 { fill: var(--seq2); } .hm3 { fill: var(--seq3); } .hm4 { fill: var(--seq4); }
.legend { display: flex; align-items: center; gap: 4px; flex-wrap: wrap; margin-top: 6px; }
.sw { display: inline-block; width: 12px; height: 12px; border-radius: 3px; }
i.sw.hm1 { background: var(--seq1); } i.sw.hm2 { background: var(--seq2); } i.sw.hm3 { background: var(--seq3); } i.sw.hm4 { background: var(--seq4); }
.sw.m-done, .mbar .m-done { background: var(--m-done); }
.sw.m-learn, .mbar .m-learn { background: var(--m-learn); }
.sw.m-none { background: var(--panel-2); border: 1px solid var(--line); }
.tip { position: absolute; pointer-events: none; background: var(--ink); color: var(--bg); font-size: .82rem; line-height: 1.4; padding: 6px 9px; border-radius: 7px; white-space: nowrap; z-index: 2; }
.mrow { display: grid; grid-template-columns: 150px 1fr 80px; gap: 12px; align-items: center; padding: 6px 0; }
.mbar { display: flex; gap: 2px; height: 14px; background: var(--panel-2); border-radius: 4px; overflow: hidden; }
.mbar i { display: block; height: 100%; border-radius: 4px; }
.badge { opacity: .6; }
.badge.on { opacity: 1; border-color: var(--accent); }
.badge .bico { font-size: 1.7rem; width: 42px; text-align: center; }
.badge:not(.on) .bico { filter: grayscale(1); }
@media (max-width: 760px) { .mrow { grid-template-columns: 1fr 70px; } .mrow .mbar { grid-column: 1 / -1; grid-row: 2; } }
.badge .row { flex-wrap: nowrap; align-items: flex-start; }

/* group chips coloured by completion (setup screens) */
.chip.grp.prog { background: linear-gradient(90deg, var(--prog-fill, var(--ok-soft)) var(--p), var(--panel) var(--p)); }
.chip.grp.full { background: var(--ok-soft); border-color: var(--ok); color: var(--ok); }
.chip.grp.full-weak { background: var(--warn-soft); border-color: var(--warn); color: var(--warn); }
.chip.grp.full .muted, .chip.grp.full-weak .muted { color: inherit; opacity: .8; }
.chip.grp.on { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent); color: var(--accent); font-weight: 600; }
.chip.grp.on:not(.prog) { background: var(--accent-soft); }
.chips { row-gap: 8px; }
:root[data-theme="dark"] { --prog-fill: #1f5a3a; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --prog-fill: #1f5a3a; } }

/* home page */
.grid.lessons { grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); }
.lesson-card.current { border-color: var(--accent); }
.mbar .m-bad { background: var(--bad); opacity: .75; }
.badge-chip { cursor: default; background: var(--ok-soft); border-color: var(--ok); color: var(--ok); }
details > summary { cursor: pointer; }

/* Anki-style study calendar (green ramp validated with the dataviz script) */
:root { --hm0: #ebeae6; --hm1: #7cc47a; --hm2: #46a64b; --hm3: #2b8a3e; --hm4: #17632a; }
:root[data-theme="dark"] { --hm0: #2a2e33; --hm1: #1f5a2c; --hm2: #2f8540; --hm3: #4caf5a; --hm4: #8fd88c; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --hm0: #2a2e33; --hm1: #1f5a2c; --hm2: #2f8540; --hm3: #4caf5a; --hm4: #8fd88c; } }
.hm0 { fill: var(--hm0); } .hm1 { fill: var(--hm1); } .hm2 { fill: var(--hm2); } .hm3 { fill: var(--hm3); } .hm4 { fill: var(--hm4); }
.plot rect.future { opacity: .45; }
.plot rect.today { stroke: var(--ink); stroke-width: 1.5; }
.hm-today { text-align: center; margin: 4px 0 10px; }
.hm-nav { display: flex; justify-content: center; gap: 6px; margin-bottom: 10px; }
.hm-scroll { display: flex; justify-content: center; overflow-x: auto; }
.hm-year { text-align: center; font-size: .78rem; color: var(--ink-3); margin-top: 4px; }
.hm-stats { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 24px; margin-top: 10px; font-size: .95rem; }
.hm-stats b { color: var(--hm3); }
.hm-stats b.zero { color: var(--ink-3); }
i.sw.hm1 { background: var(--hm1); } i.sw.hm2 { background: var(--hm2); } i.sw.hm3 { background: var(--hm3); } i.sw.hm4 { background: var(--hm4); }
.doc-frame { width: 100%; height: calc(100vh - 170px); min-height: 480px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel-2); }
.exam-clock { font-weight: 700; font-variant-numeric: tabular-nums; padding: 3px 10px; border-radius: 999px; background: var(--panel-2); margin-right: 10px; }
.exam-clock.low { background: var(--bad, #d9534f); color: #fff; }