/* Answer-sheet theme: rose for printed marks, graphite for what the student fills in, pencil yellow for details still to be filled in. */
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; }
img { max-width: 100%; }
[hidden] { display: none !important; }
:root {
  --paper: #eff2f0;
  --sheet: #ffffff;
  --ink: #1c2126;
  --muted: #566069;
  --rule: #d6dcdc;
  --dropout: #bd2149;
  --dropout-soft: #fbe7ec;
  --graphite: #262a30;
  --on-graphite: #ffffff;
  --pencil: #ffd84d;
  --on-pencil: #1c2126;
  --ok: #0f6b46;
  --ok-soft: #def3e9;
  --bad: #b3261e;
  --bad-soft: #fbe5e3;
  --display: "Bai Jamjuree", "Sarabun", "Leelawadee UI", Tahoma, sans-serif;
  --body: "Sarabun", "Leelawadee UI", Tahoma, sans-serif;
  --exam: "Source Serif 4", Georgia, "Times New Roman", serif;
  --mono: "IBM Plex Mono", Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #12151a; --sheet: #1a1e24; --ink: #e9ecee; --muted: #a2abb3; --rule: #333a42;
    --dropout: #ff87a0; --dropout-soft: #3b1c26; --graphite: #e9ecee; --on-graphite: #12151a;
    --ok: #62d6a5; --ok-soft: #12362b; --bad: #ff8f85; --bad-soft: #3e1d1b;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #12151a; --sheet: #1a1e24; --ink: #e9ecee; --muted: #a2abb3; --rule: #333a42;
  --dropout: #ff87a0; --dropout-soft: #3b1c26; --graphite: #e9ecee; --on-graphite: #12151a;
  --ok: #62d6a5; --ok-soft: #12362b; --bad: #ff8f85; --bad-soft: #3e1d1b;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { background: var(--paper); color: var(--ink); font: 400 17px/1.7 var(--body); }
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); z-index: 10; background: var(--sheet); }
h1, h2, h3 { font-family: var(--display); line-height: 1.25; margin: 0; text-wrap: balance; }
h1 { font-size: clamp(2rem, 5vw, 3.25rem); font-weight: 700; }
h2 { font-size: clamp(1.55rem, 3.2vw, 2.15rem); font-weight: 700; }
h3 { font-size: 1.15rem; font-weight: 600; }
p { margin: 0; }
a { color: var(--dropout); }
section[id] { scroll-margin-top: 76px; }
:focus-visible { outline: 3px solid var(--dropout); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { transition: none !important; } }

.wrap { max-width: 1160px; margin-inline: auto; padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); }
.band { padding-block: clamp(48px, 7vw, 84px); }
.band-sheet { background: var(--sheet); border-block: 1px solid var(--rule); }
.head { display: grid; gap: 10px; max-width: 44rem; margin-bottom: 32px; }
.lede { color: var(--muted); }
.eyebrow { font: 600 .82rem/1.4 var(--mono); letter-spacing: .06em; color: var(--dropout); }
.fill { background: var(--pencil); color: var(--on-pencil); padding: 0 .3em; border-radius: 2px; font-weight: 500; }

.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 8px 20px; border: 1.5px solid var(--graphite); border-radius: 4px; background: var(--graphite); color: var(--on-graphite); font: 600 1rem/1.3 var(--display); text-decoration: none; cursor: pointer; }
.btn:hover { opacity: .88; }
.btn-ghost { background: transparent; color: var(--ink); }
.btn-row { display: flex; flex-wrap: wrap; gap: 10px; }

/* Top bar */
.top { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 9; background: var(--sheet); border-bottom: 1px solid var(--rule); }
.top .wrap { display: flex; align-items: center; justify-content: space-between; gap: 8px 20px; flex-wrap: wrap; padding-block: 10px; }
.brand { font: 700 1.05rem/1.3 var(--display); color: var(--ink); text-decoration: none; }
.top nav { display: flex; flex-wrap: wrap; gap: 2px 18px; }
.top nav a { color: var(--ink); text-decoration: none; font-weight: 500; font-size: .97rem; }
.top nav a:hover { color: var(--dropout); }

/* Answer-sheet surface with OMR timing marks down the left edge */
.sheet { position: relative; background: var(--sheet); border: 1px solid var(--rule); padding: 22px 22px 22px 44px; min-width: 0; }
.sheet::before { content: ""; position: absolute; top: 14px; bottom: 14px; left: 14px; width: 12px; background: repeating-linear-gradient(to bottom, var(--graphite) 0 5px, transparent 5px 19px); }

/* Hero */
.hero { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr); gap: clamp(28px, 5vw, 64px); align-items: center; padding-block: clamp(36px, 6vw, 72px); }
.hero-copy { display: grid; gap: 18px; min-width: 0; }
.hero-copy > p:not(.eyebrow) { font-size: 1.12rem; max-width: 34rem; }
.sheet-label { font: 600 .78rem/1.4 var(--mono); letter-spacing: .05em; color: var(--dropout); display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; border-bottom: 1px solid var(--dropout); padding-bottom: 8px; margin-bottom: 14px; }

/* Bubbles */
.opts { display: grid; gap: 6px; list-style: none; margin: 12px 0 0; padding: 0; }
.opts.row { display: flex; flex-wrap: wrap; gap: 6px 10px; }
.opt-text:empty { display: none; }
.result, #paper { scroll-margin-top: 80px; }
.opt { position: relative; display: flex; align-items: flex-start; gap: 12px; padding: 5px 6px; border-radius: 4px; cursor: pointer; }
.opt:hover { background: var(--dropout-soft); }
.opt input { position: absolute; opacity: 0; width: 32px; height: 32px; margin: 0; cursor: inherit; }
.bub { flex: none; width: 32px; height: 32px; border: 1.5px solid var(--dropout); border-radius: 50%; color: var(--dropout); display: grid; place-items: center; font: 600 .85rem/1 var(--mono); }
.opt-text { font-family: var(--exam); font-size: 1.04rem; line-height: 1.5; padding-top: 3px; min-width: 0; }
.opt input:checked + .bub { background: var(--graphite); border-color: var(--graphite); color: var(--on-graphite); }
.opt input:focus-visible + .bub { outline: 3px solid var(--dropout); outline-offset: 2px; }
.locked .opt { cursor: default; }
.locked .opt:hover { background: none; }
.opt.is-ans .bub, .opt.is-ans input:checked + .bub { background: var(--ok); border-color: var(--ok); color: var(--sheet); }
.opt.is-wrong .bub, .opt.is-wrong input:checked + .bub { background: var(--bad); border-color: var(--bad); color: var(--sheet); }

.stem { font-family: var(--exam); font-size: 1.1rem; line-height: 1.55; }
.stem u { text-decoration-thickness: 1.5px; text-underline-offset: 3px; }
.stem sup { font: 600 .68rem/1 var(--mono); color: var(--dropout); margin-left: 1px; }
.why { margin-top: 12px; padding: 12px 14px; border-radius: 4px; background: var(--ok-soft); font-size: .98rem; }
.why.miss { background: var(--bad-soft); }
.why strong { font-family: var(--display); }
.why .say { font-family: var(--exam); margin-top: 8px; padding-top: 8px; border-top: 1px solid currentColor; }

/* Exam comparison */
.exams { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: clamp(20px, 3vw, 36px); }
.exam { display: flex; flex-direction: column; gap: 14px; border-top: 3px solid var(--dropout); padding-top: 14px; min-width: 0; }
.exam h3 { font-size: 1.5rem; font-weight: 700; }
.exam dl { display: grid; grid-template-columns: 5.2rem minmax(0, 1fr); gap: 4px 10px; margin: 0; font-size: .97rem; }
.exam dt { color: var(--muted); }
.exam dd { margin: 0; font-weight: 500; }
.exam .num { font-family: var(--mono); font-variant-numeric: tabular-nums; font-weight: 500; }
.split { display: flex; gap: 2px; height: 14px; }
.split span { display: block; min-width: 0; }
.s1 { background: var(--dropout); } .s2 { background: var(--graphite); } .s3 { background: var(--pencil); }
.key { display: grid; gap: 2px; margin: 0; padding: 0; list-style: none; font-size: .92rem; color: var(--muted); }
.key li { display: flex; gap: 8px; align-items: center; }
.key i { flex: none; width: 10px; height: 10px; }
.exam .btn { margin-top: auto; }
.footnote { margin-top: 26px; font-size: .92rem; color: var(--muted); max-width: 48rem; }

/* Practice */
.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.tab { min-height: 46px; padding: 8px 22px; border: 1.5px solid var(--dropout); border-radius: 4px; background: transparent; color: var(--dropout); font: 600 1.02rem/1.2 var(--display); cursor: pointer; }
.tab[aria-selected="true"] { background: var(--graphite); border-color: var(--graphite); color: var(--on-graphite); }
.practice { display: grid; grid-template-columns: minmax(0, 1fr) 264px; gap: 20px; align-items: start; }
.paper-head { display: grid; gap: 6px; padding-bottom: 14px; margin-bottom: 8px; border-bottom: 1px solid var(--dropout); }
.paper-head p { color: var(--muted); font-size: .97rem; }
.group { padding-top: 24px; }
.group > h3 { color: var(--dropout); }
.instr { color: var(--muted); font-size: .96rem; margin-top: 2px; }
.passage { font-family: var(--exam); font-size: 1.06rem; line-height: 1.65; max-width: 42rem; margin-top: 12px; padding: 14px 16px; border: 1px solid var(--rule); display: grid; gap: 8px; }
.q { display: grid; grid-template-columns: 2.2rem minmax(0, 1fr); gap: 0 6px; margin: 0; padding: 18px 0; min-width: 0; border: 0; border-bottom: 1px solid var(--rule); scroll-margin-top: 80px; }
.group .q:last-child { border-bottom: 0; }
.q-n { font: 600 1rem/1.7 var(--mono); color: var(--dropout); font-variant-numeric: tabular-nums; }
.q-body { min-width: 0; }
.audio { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 14px; margin-bottom: 8px; }
.play { min-height: 40px; padding: 4px 16px; border: 1.5px solid var(--graphite); border-radius: 4px; background: transparent; color: var(--ink); font: 600 .95rem/1.2 var(--display); cursor: pointer; }
.play[aria-pressed="true"] { background: var(--graphite); color: var(--on-graphite); }
.audio details { font-size: .95rem; }
.audio summary { cursor: pointer; color: var(--muted); }
.script { font-family: var(--exam); margin-top: 6px; }
.audio-note { font-size: .92rem; color: var(--bad); }
.hear { color: var(--muted); font-size: .95rem; }

/* Mini answer sheet */
.side { position: sticky; top: 76px; align-self: start; background: var(--sheet); border: 1px solid var(--rule); padding: 14px; display: grid; gap: 12px; }
.side-count { font: 600 .9rem/1.4 var(--mono); font-variant-numeric: tabular-nums; }
.mini { display: grid; gap: 4px; max-height: 52vh; overflow-y: auto; }
.mini-row { display: flex; align-items: center; gap: 5px; }
.mini-n { width: 2rem; padding: 0; border: 0; background: none; color: var(--dropout); text-align: left; font: 600 .82rem/1.8 var(--mono); cursor: pointer; }
.mini-b { width: 24px; height: 24px; border: 1.25px solid var(--dropout); border-radius: 50%; display: grid; place-items: center; color: var(--dropout); font: 500 .66rem/1 var(--mono); cursor: pointer; }
.mini-b.on { background: var(--graphite); border-color: var(--graphite); color: var(--on-graphite); }
.mini-b.ans { background: var(--ok); border-color: var(--ok); color: var(--sheet); }
.mini-b.wrong { background: var(--bad); border-color: var(--bad); color: var(--sheet); }
.side .btn { width: 100%; }

/* Result */
.result { margin-bottom: 20px; display: grid; gap: 14px; }
.result h3 { font-size: 1.3rem; }
.score { font: 600 clamp(2.6rem, 7vw, 3.6rem)/1 var(--mono); font-variant-numeric: tabular-nums; }
.score small { font-size: .5em; color: var(--muted); }
.bars { display: grid; gap: 8px; max-width: 34rem; }
.bar-row { display: grid; grid-template-columns: minmax(0, 1fr) 3rem; gap: 2px 10px; font-size: .95rem; }
.bar-row b { font: 500 .92rem/1.7 var(--mono); text-align: right; font-variant-numeric: tabular-nums; }
.bar { grid-column: 1 / -1; height: 8px; background: var(--dropout-soft); }
.bar span { display: block; height: 100%; background: var(--dropout); }
.notice { font-size: .95rem; color: var(--muted); }

/* Teaching */
.steps { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 24px; margin: 0; padding: 0; list-style: none; }
.steps li { display: grid; gap: 6px; align-content: start; }
.step-n { width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center; background: var(--graphite); color: var(--on-graphite); font: 600 .95rem/1 var(--mono); }
.steps p, .course p { color: var(--muted); font-size: .98rem; }
.courses { margin-top: 44px; display: grid; }
.course { display: grid; grid-template-columns: minmax(0, 15rem) minmax(0, 1fr) auto; gap: 6px 24px; padding-block: 16px; border-top: 1px solid var(--rule); align-items: baseline; }
.course:last-child { border-bottom: 1px solid var(--rule); }

/* About and contact */
.about { display: grid; grid-template-columns: minmax(0, 280px) minmax(0, 1fr); gap: clamp(24px, 4vw, 52px); align-items: start; }
.photo { display: block; width: 100%; height: auto; aspect-ratio: 4 / 5; object-fit: cover; border: 1px solid var(--rule); }
.about-copy { display: grid; gap: 16px; min-width: 0; }
.facts { display: grid; grid-template-columns: 8.5rem minmax(0, 1fr); gap: 8px 16px; margin: 0; }
.facts dt { color: var(--muted); }
.facts dd { margin: 0; }
.contact { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: clamp(24px, 4vw, 52px); align-items: start; }
.contact-list { display: grid; gap: 12px; margin: 0; }
.contact-list div { display: grid; grid-template-columns: 5.5rem minmax(0, 1fr); gap: 12px; align-items: baseline; }
.contact-list dt { color: var(--dropout); font: 600 .85rem/1.6 var(--mono); }
.contact-list dd { margin: 0; }
footer { padding-block: 28px; font-size: .9rem; color: var(--muted); }

@media (max-width: 940px) {
  .hero, .contact { grid-template-columns: minmax(0, 1fr); }
  .exams { grid-template-columns: minmax(0, 1fr); }
  .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .practice { grid-template-columns: minmax(0, 1fr); }
  .side { top: auto; bottom: 0; grid-template-columns: auto minmax(0, 1fr); align-items: center; padding: 10px 12px calc(10px + env(safe-area-inset-bottom, 0px)); }
  .mini { display: none; }
  .course { grid-template-columns: minmax(0, 1fr) auto; }
  .course p { grid-column: 1 / -1; grid-row: 2; }
}
@media (max-width: 600px) {
  body { font-size: 16px; }
  .steps, .about { grid-template-columns: minmax(0, 1fr); }
  .photo { max-width: 220px; }
  .sheet { padding: 16px 14px 16px 32px; }
  .sheet::before { left: 10px; width: 9px; }
  .q { grid-template-columns: 1.9rem minmax(0, 1fr); }
  .facts { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .facts dd { margin-bottom: 10px; }
  .top .wrap { flex-direction: column; align-items: stretch; flex-wrap: nowrap; gap: 2px; padding-block: 6px; }
  .top nav { flex-wrap: nowrap; gap: 0 14px; overflow-x: auto; white-space: nowrap; }
  .top nav a { font-size: .92rem; }
}

/* Reviews */
.reviews { display: grid; grid-template-columns: minmax(0, 2fr) minmax(0, 1fr) minmax(0, 1fr); gap: clamp(20px, 3vw, 36px); }
.review { display: flex; flex-direction: column; justify-content: space-between; gap: 14px; margin: 0; border-top: 3px solid var(--dropout); padding-top: 14px; min-width: 0; }
.review blockquote { margin: 0; font-size: 1.08rem; }
.review figcaption { color: var(--muted); font-size: .92rem; }
.facts .num { font-family: var(--mono); font-weight: 500; }
@media (max-width: 940px) { .reviews { grid-template-columns: minmax(0, 1fr); } }
.s4 { background: var(--muted); }
.price { font-family: var(--display); font-weight: 600; white-space: nowrap; }
@media (max-width: 1040px) and (min-width: 941px) { .exams { grid-template-columns: repeat(2, minmax(0, 1fr)); } }

/* Logo in the top bar */
.brand { display: inline-flex; align-items: center; }
.brand img { display: block; height: 50px; width: auto; }
@media (max-width: 600px) { .brand img { height: 42px; } }