/* Layout: one book page, centred; a sticky module bar with Teacher/Student modes; exercise blocks of question cards; a speaking showcase below. */
:root {
  --paper: #ffffff; --ground: var(--t-ground); --ink: #1d2433; --mute: #5d6678; --line: var(--t-line);
  --accent: var(--t-accent); --accent-deep: var(--t-deep); --tint: var(--t-tint); --tint2: var(--t-tint2); --soft: var(--t-soft);
  --ok: #157a4a; --ok-tint: var(--ok-tint); --bad: #b42335; --bad-tint: var(--bad-tint); --on-accent: #ffffff; --mark: var(--t-mark);
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
}



* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { background: var(--ground); color: var(--ink); font: 400 15px/1.55 var(--sans);
  padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); padding-block: 0 56px; }
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); z-index: 10; background: var(--accent-deep); }
button { font: inherit; cursor: pointer; }
button:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
.page { max-width: 860px; margin: 0 auto; }

.mast { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 20px; padding: 22px 0 14px; }
.mast img { height: 34px; width: auto; background: var(--t-paper); border-radius: 6px; padding: 4px 8px; }
.mast .ed { font: 700 11px/1 var(--sans); letter-spacing: .14em; text-transform: uppercase; color: var(--accent); }
.mast h1 { flex-basis: 100%; margin: 4px 0 0; font: 800 clamp(24px, 4.6vw, 34px)/1.12 var(--sans); letter-spacing: -.02em; color: var(--accent-deep); text-wrap: balance; }
.mast .sub { flex-basis: 100%; margin: 0; color: var(--mute); }

/* module bar */
.bar { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 5; display: flex; flex-wrap: wrap; align-items: center; gap: 8px 10px;
  background: var(--t-deep); color: #fff; border-radius: 14px; padding: 10px 12px; margin: 8px 0 22px; box-shadow: 0 8px 24px -14px rgba(30, 14, 80, .6); }
.bar .lab { font: 700 11px/1.2 var(--sans); letter-spacing: .12em; text-transform: uppercase; opacity: .8; margin-right: auto; }
.bar .lab b { display: block; font-size: 15px; letter-spacing: 0; text-transform: none; opacity: 1; margin-top: 3px; }
.modes { display: inline-flex; background: rgba(255,255,255,.12); border-radius: 999px; padding: 3px; }
.modes button { border: 0; background: transparent; color: #fff; border-radius: 999px; padding: 6px 14px; font-weight: 700; font-size: 13px; }
.modes button[aria-pressed="true"] { background: var(--t-paper); color: var(--t-deep); }
.btn { display: inline-flex; align-items: center; gap: 7px; border: 1.5px solid currentColor; background: transparent; color: inherit;
  border-radius: 999px; padding: 7px 14px; font-weight: 600; font-size: 13.5px; white-space: nowrap; }
.btn svg { width: 16px; height: 16px; flex: none; }
.bar .btn { color: #fff; }
.bar .btn.solid, .bar .btn[aria-pressed="true"] { background: var(--t-paper); border-color: #fff; color: var(--t-deep); }
.btn.ghost { border-color: var(--line); color: var(--accent-deep); background: var(--paper); }
.btn.ghost[aria-pressed="true"] { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }

.part { background: var(--paper); border: 1px solid var(--line); border-top: 5px solid var(--accent); border-radius: 0 0 14px 14px; padding: 22px clamp(16px, 4vw, 30px); }
.part h2 { margin: 0 0 4px; font: 800 24px/1.2 var(--sans); color: var(--accent-deep); letter-spacing: -.01em; text-wrap: balance; }
.part .inst { margin: 0; color: var(--mute); }
.realtest { display: flex; gap: 12px; align-items: flex-start; margin-top: 16px; background: var(--tint); border-radius: 12px; padding: 12px 14px; font-size: 14px; }
.realtest svg { width: 22px; height: 22px; flex: none; color: var(--accent); margin-top: 1px; }

.ex { margin-top: 26px; }
.ex-head { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 12px; border-bottom: 2px solid var(--accent); padding-bottom: 10px; margin-bottom: 14px; }
.ex-head h3 { margin: 0 auto 0 0; font: 800 19px/1.2 var(--sans); color: var(--accent-deep); }
.ex-head h3 span { display: block; font: 600 12.5px/1.3 var(--sans); color: var(--mute); margin-top: 2px; }
.player { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; background: var(--paper); border: 1px solid var(--line); border-radius: 12px; padding: 10px 12px; margin-bottom: 14px; }
.player .tag { font: 700 11px/1.2 var(--sans); letter-spacing: .1em; text-transform: uppercase; color: var(--accent); white-space: nowrap; }
.player audio { flex: 1 1 260px; min-width: 0; height: 38px; }
.score { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 16px; background: var(--accent-deep); color: #fff; border-radius: 12px; padding: 12px 16px; margin: 0 0 14px; }
.score b { font: 800 22px/1 var(--sans); }
.score small { opacity: .85; }

/* transcript */
.transcript { background: var(--paper); border: 1px solid var(--line); border-radius: 12px; padding: 6px 16px; margin: 0 0 14px; max-height: 340px; overflow-y: auto; }
.tl { display: grid; grid-template-columns: 70px 1fr; gap: 10px; padding: 7px 0; border-bottom: 1px dashed var(--line); font: 400 15px/1.5 var(--serif); }
.tl:last-child { border-bottom: 0; }
.tl .who { font: 700 11.5px/1.9 var(--sans); letter-spacing: .06em; text-transform: uppercase; color: var(--accent); }
.tl.now { background: var(--tint); border-radius: 8px; padding-inline: 8px; margin-inline: -8px; }
mark { background: transparent; color: inherit; }
.transcript.reveal mark, .tl.now mark { background: var(--mark); color: var(--ink); border-radius: 3px; padding: 0 2px; }

.tabs { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 10px; }
.tabs a, .tabs span { border: 1.5px solid var(--line); background: var(--paper); color: var(--accent-deep); border-radius: 999px; padding: 6px 14px; font: 700 13px/1.2 var(--sans); text-decoration: none; }
.tabs a[aria-current="page"] { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.tabs span { opacity: .5; }
.tests { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin: 0 0 6px; font: 600 12.5px/1.2 var(--sans); color: var(--mute); }
.tests a { display: inline-grid; place-items: center; min-width: 30px; height: 30px; border-radius: 8px; border: 1.5px solid var(--line); background: var(--paper); color: var(--accent-deep); text-decoration: none; font-weight: 700; }
.tests a[aria-current="page"] { background: var(--accent-deep); border-color: var(--accent-deep); color: #fff; }
.jump { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 6px; }
.jump a { font: 600 12.5px/1 var(--sans); color: var(--accent-deep); background: var(--paper); border: 1px solid var(--line); border-radius: 999px; padding: 6px 10px; text-decoration: none; }