/* English My Way, Book 3, Episode 18
   Palette comes from the printed book: its blue (Unit 37) and its red (Unit 38). */

:root {
  --paper: #f6f7fb;
  --surface: #ffffff;
  --ink: #141b2d;
  --muted: #566079;
  --line: #d9ddea;
  --blue: #2347c8;
  --red: #c42b3a;
  --mark: #ffe169;
  --on-accent: #ffffff;
  --ok: #17794a;
  --bad: #b3261e;
  --accent: var(--blue);

  --sans: "Bricolage Grotesque", "Segoe UI", system-ui, -apple-system, sans-serif;
  --serif: "Literata", Georgia, "Times New Roman", serif;

  --gutter: 1.25rem;
  color-scheme: light dark;
}

/* The inline script in <head> always sets data-theme (saved choice, else system).
   The media query below is only the fallback for when JavaScript is off. */
:root[data-theme="light"] { color-scheme: light; }
:root[data-theme="dark"] { color-scheme: dark; }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0e1322;
    --surface: #161d31;
    --ink: #e9edf9;
    --muted: #9aa5c4;
    --line: #2a3350;
    --blue: #93a9ff;
    --red: #ff9aa3;
    --mark: #6b5a12;
    --on-accent: #0e1322;
    --ok: #62d49b;
    --bad: #ff8b84;
  }
}
:root[data-theme="dark"] {
  --paper: #0e1322;
  --surface: #161d31;
  --ink: #e9edf9;
  --muted: #9aa5c4;
  --line: #2a3350;
  --blue: #93a9ff;
  --red: #ff9aa3;
  --mark: #6b5a12;
  --on-accent: #0e1322;
  --ok: #62d49b;
  --bad: #ff8b84;
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 4.5rem; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 1.0625rem/1.7 var(--serif);
  -webkit-text-size-adjust: 100%;
}

h1, h2, h3, h4, .sans { font-family: var(--sans); }
h1, h2, h3, h4 { line-height: 1.15; margin: 0; letter-spacing: -0.01em; }
p { margin: 0 0 1em; }
a { color: var(--accent); text-underline-offset: 0.2em; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

.wrap { max-width: 1120px; margin: 0 auto; padding: 0 var(--gutter); }

.skip {
  position: absolute; left: var(--gutter); top: -4rem;
  background: var(--ink); color: var(--paper); padding: 0.6rem 1rem; z-index: 20;
  font: 600 0.95rem var(--sans);
}
.skip:focus { top: 0.5rem; }

.sr-only {
  position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

mark { background: var(--mark); color: inherit; padding: 0 0.15em; border-radius: 3px; }

/* ---------- Page chrome ---------- */
[hidden] { display: none !important; }

.theme-btn {
  appearance: none; cursor: pointer; display: inline-flex; align-items: center; gap: 0.5rem;
  font: 600 0.9rem var(--sans); color: var(--ink); background: transparent;
  border: 1.5px solid var(--line); border-radius: 999px; padding: 0.35rem 0.8rem 0.35rem 0.6rem;
}
.theme-btn:hover { border-color: var(--ink); }
.theme-btn svg { width: 1.1rem; height: 1.1rem; fill: currentColor; flex: none; }
.theme-btn .i-sun { display: none; }
:root[data-theme="dark"] .theme-btn .i-sun { display: block; }
:root[data-theme="dark"] .theme-btn .i-moon { display: none; }

.btn {
  display: inline-block; font: 700 1rem var(--sans); text-decoration: none; cursor: pointer;
  background: var(--accent); color: var(--on-accent); border: 1.5px solid var(--accent); padding: 0.65rem 1.2rem; border-radius: 999px;
}
.btn:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--ink); }

/* ---------- Hero ---------- */
.hero { padding: clamp(1.25rem, 3vw, 2rem) 0 clamp(2rem, 5vw, 3.5rem); border-bottom: 1px solid var(--line); }
.hero-top { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: clamp(2.5rem, 8vw, 5.5rem); }
.series { margin: 0; font: 600 0.95rem var(--sans); color: var(--muted); }
.hero h1 { font-weight: 800; font-size: clamp(2.3rem, 6.4vw, 4.8rem); letter-spacing: -0.03em; max-width: 15ch; text-wrap: balance; }
.hero .lede { max-width: 54ch; margin: 1.5rem 0 0; font-size: 1.15rem; color: var(--muted); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin: 1.75rem 0 0; }

/* ---------- Layout and contents list ---------- */
.layout { max-width: 1120px; margin: 0 auto; padding: 0 var(--gutter); display: block; }
@media (min-width: 960px) {
  .layout { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 3.5rem; }
  html { scroll-padding-top: 1.5rem; }
}

/* Phones: a sticky strip that scrolls sideways. Desktop: a sticky list with the open topic expanded. */
.toc {
  position: sticky; top: 0; z-index: 5; background: var(--paper);
  margin: 0 calc(var(--gutter) * -1); padding: 0 var(--gutter); border-bottom: 1px solid var(--line);
}
.toc .toc-title, .toc .sub, .toc .theme-btn { display: none; }
.toc ol { list-style: none; margin: 0; padding: 0.6rem 0; display: flex; gap: 0.4rem; overflow-x: auto; scrollbar-width: none; }
.toc ol::-webkit-scrollbar { display: none; }
.toc ol > li { flex: none; }
.toc ol > li > a {
  display: flex; gap: 0.45rem; align-items: baseline; white-space: nowrap;
  font: 600 0.9rem var(--sans); color: var(--ink); text-decoration: none;
  padding: 0.35rem 0.8rem; border: 1px solid var(--line); border-radius: 999px;
}
.toc .num { color: var(--muted); font-weight: 700; }
.toc ol > li > a[aria-current="true"] { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }
.toc ol > li > a[aria-current="true"] .num { color: inherit; }

@media (min-width: 960px) {
  .toc { top: 1.5rem; align-self: start; margin: 0; padding: 0; background: none; border: 0; max-height: calc(100vh - 3rem); overflow-y: auto; }
  .toc .toc-title { display: block; font: 700 0.95rem var(--sans); margin: 0 0 0.75rem; }
  .toc ol { flex-direction: column; gap: 0; padding: 0; overflow: visible; border-left: 2px solid var(--line); }
  .toc ol > li > a {
    border: 0; border-radius: 0; padding: 0.45rem 0 0.45rem 1rem; margin-left: -2px; border-left: 2px solid transparent;
    white-space: normal;
  }
  .toc ol > li > a:hover { color: var(--accent); }
  .toc ol > li > a[aria-current="true"] { background: none; color: var(--accent); border-left-color: var(--accent); }
  .toc li.open > .sub { display: block; }
  .toc .sub { list-style: none; margin: 0 0 0.5rem; padding: 0; }
  .toc .sub a {
    display: block; font: 500 0.88rem var(--sans); color: var(--muted); text-decoration: none;
    padding: 0.25rem 0 0.25rem 2.4rem; margin-left: -2px; border-left: 2px solid transparent;
  }
  .toc .sub a:hover { color: var(--accent); }
  .toc .sub a[aria-current="true"] { color: var(--ink); font-weight: 700; }
  .toc .theme-btn { display: inline-flex; margin-top: 1.25rem; }
  .hero .theme-btn { display: none; }
}

.to-top {
  position: fixed; right: 1rem; bottom: 1rem; z-index: 10; width: 2.75rem; height: 2.75rem; border-radius: 50%;
  display: grid; place-items: center; background: var(--ink); color: var(--paper);
}
.to-top svg { width: 1.2rem; height: 1.2rem; fill: currentColor; }

/* Shown when the device can't read aloud. */
.toast {
  position: fixed; left: 50%; bottom: 1rem; transform: translateX(-50%); z-index: 20;
  width: max-content; max-width: min(34rem, calc(100vw - 2rem));
  background: var(--ink); color: var(--paper); font: 600 0.95rem/1.45 var(--sans);
  padding: 0.8rem 1.1rem; border-radius: 10px;
}

/* ---------- Topics and sections ---------- */
.content { min-width: 0; padding-bottom: 3rem; }

.topic { padding-top: 0.5rem; }
.topic + .topic { margin-top: 3.5rem; padding-top: 3rem; border-top: 3px solid var(--ink); }
.topic-head { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 0 clamp(1rem, 3vw, 2rem); align-items: start; padding-top: 1.25rem; }
.step-num { font: 800 clamp(3.5rem, 9vw, 6rem)/0.8 var(--sans); letter-spacing: -0.05em; color: var(--accent); margin: 0; }
.topic-head h2 { font-size: clamp(1.9rem, 4.5vw, 3rem); font-weight: 800; letter-spacing: -0.025em; text-wrap: balance; }
.topic-head .lead { margin: 0.9rem 0 0.5rem; max-width: 58ch; font-size: 1.1rem; color: var(--muted); }
.topic-head .pages { margin: 0; font: 500 0.9rem var(--sans); color: var(--muted); }

.block { padding: 2.5rem 0 1rem; border-top: 1px solid var(--line); }
.topic-head + .block { border-top: 0; padding-top: 1.75rem; }
.block-head { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem 0.9rem; margin-bottom: 1.25rem; }
.sec-title { font-size: clamp(1.45rem, 3vw, 1.9rem); font-weight: 800; letter-spacing: -0.02em; }

/* Where this section sits in the printed book. */
.skill {
  font: 600 0.85rem var(--sans); color: var(--muted); border: 1px solid var(--line);
  padding: 0.2rem 0.7rem; border-radius: 999px; text-decoration: none;
}
a.skill { color: var(--accent); border-color: var(--accent); }
a.skill:hover { background: var(--accent); color: var(--on-accent); }

.block h4 { font-size: 1.3rem; font-weight: 700; margin: 2rem 0 0.6rem; }
.block h4:first-child { margin-top: 0; }
.block h5 { font-size: 1.05rem; font-weight: 700; margin: 1.5rem 0 0.4rem; color: var(--accent); }
.intro { color: var(--muted); max-width: 62ch; }
.block p, .block li { max-width: 68ch; }

.note-added {
  font: 500 0.85rem var(--sans); color: var(--muted); border-left: 3px solid var(--line); padding-left: 0.8rem; max-width: 62ch;
}

/* ---------- Dialogue ---------- */
.script { list-style: none; margin: 0; padding: 0; max-width: 760px; }
.script li {
  display: grid; grid-template-columns: 7.5rem minmax(0, 1fr) auto; gap: 0.25rem 1rem;
  padding: 0.7rem 0; border-top: 1px solid var(--line); align-items: baseline;
}
.script li:first-child { border-top: 0; }
.script .who { font: 700 0.95rem var(--sans); display: flex; align-items: center; gap: 0.5rem; }
.script .who::before { content: ""; width: 0.65rem; height: 0.65rem; border-radius: 50%; background: var(--c, var(--muted)); flex: none; }
.script p { margin: 0; }
.script .scene-break { display: block; border-top: 0; padding: 1.4rem 0 0.4rem; font: italic 500 0.95rem var(--serif); color: var(--muted); }
[data-c="1"] { --c: #2347c8; } [data-c="2"] { --c: #c42b3a; } [data-c="3"] { --c: #0e7c7b; } [data-c="4"] { --c: #b8730a; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) [data-c="1"] { --c: #93a9ff; }
  :root:not([data-theme="light"]) [data-c="2"] { --c: #ff9aa3; }
  :root:not([data-theme="light"]) [data-c="3"] { --c: #5fd3d1; }
  :root:not([data-theme="light"]) [data-c="4"] { --c: #f5b960; }
}
:root[data-theme="dark"] [data-c="1"] { --c: #93a9ff; }
:root[data-theme="dark"] [data-c="2"] { --c: #ff9aa3; }
:root[data-theme="dark"] [data-c="3"] { --c: #5fd3d1; }
:root[data-theme="dark"] [data-c="4"] { --c: #f5b960; }
@media (max-width: 600px) {
  .script li { grid-template-columns: minmax(0, 1fr) auto; }
  .script .who { grid-column: 1 / -1; }
}

.say {
  appearance: none; border: 1px solid var(--line); background: var(--surface); color: var(--ink);
  width: 2rem; height: 2rem; border-radius: 50%; padding: 0; cursor: pointer; display: inline-grid; place-items: center; flex: none;
}
.say:hover { border-color: var(--accent); color: var(--accent); }
.say[aria-pressed="true"] { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }
.say svg { width: 1rem; height: 1rem; fill: currentColor; }
.say-wide {
  appearance: none; display: inline-flex; align-items: center; gap: 0.5rem; cursor: pointer;
  font: 600 0.95rem var(--sans); border: 1px solid var(--line); background: var(--surface); color: var(--ink);
  padding: 0.45rem 1rem 0.45rem 0.6rem; border-radius: 999px; margin-bottom: 1.25rem;
}
.say-wide svg { width: 1rem; height: 1rem; fill: currentColor; }
.say-wide:hover { border-color: var(--accent); }
.say-wide[aria-pressed="true"] { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }

.phrases { margin: 2rem 0 0; padding: 0; list-style: none; max-width: 760px; }
.phrases li { padding: 0.65rem 0; border-top: 1px solid var(--line); display: grid; grid-template-columns: minmax(0, 14rem) minmax(0, 1fr); gap: 0.25rem 1.5rem; }
.phrases b { font: 700 1rem var(--sans); }
@media (max-width: 600px) { .phrases li { grid-template-columns: 1fr; } }

/* ---------- Speak up: phrase bank and speaking prompts ---------- */
.bank { list-style: none; margin: 0.75rem 0 2.25rem; padding: 0; max-width: 760px; }
.bank li {
  display: grid; grid-template-columns: minmax(0, 13rem) minmax(0, 1fr) auto; gap: 0.25rem 1.25rem;
  align-items: center; padding: 0.7rem 0; border-top: 1px solid var(--line);
}
.bank b { font: 700 1rem var(--sans); color: var(--accent); }
@media (max-width: 600px) {
  .bank li { grid-template-columns: minmax(0, 1fr) auto; }
  .bank b { grid-column: 1 / -1; }
}

.prompts { list-style: none; counter-reset: prompt; margin: 0.75rem 0 0; padding: 0; max-width: 760px; }
.prompts > li { counter-increment: prompt; padding: 1.15rem 0 1.25rem; border-top: 1px solid var(--line); }
.ask-row { display: flex; align-items: flex-start; gap: 0.8rem; }
.ask-row::before { content: counter(prompt); flex: none; min-width: 1.5rem; font: 800 1.15rem/1.45 var(--sans); color: var(--accent); }
.ask { flex: 1; margin: 0; font: 600 1.1rem/1.45 var(--sans); }
.use { margin: 0.4rem 0 0.8rem 2.3rem; font: 500 0.9rem var(--sans); color: var(--muted); }
.use span { font-weight: 700; }
.use i { font-style: normal; color: var(--ink); background: color-mix(in srgb, var(--accent) 12%, transparent); padding: 0 0.3em; border-radius: 4px; }
details.model { margin-left: 2.3rem; }
details.model summary {
  display: inline-block; cursor: pointer; list-style: none; font: 700 0.95rem var(--sans); color: var(--accent);
  text-decoration: underline; text-underline-offset: 0.2em;
}
details.model summary::-webkit-details-marker { display: none; }
details.model .s-hide, details.model[open] .s-show { display: none; }
details.model[open] .s-hide { display: inline; }
details.model[open] summary { margin-bottom: 0.7rem; }
.model-body {
  display: flex; align-items: flex-start; gap: 0.8rem; background: var(--surface);
  border: 1px solid var(--line); border-left: 4px solid var(--accent); border-radius: 8px; padding: 0.8rem 1rem;
}
.model-body p { flex: 1; margin: 0; }
.model-body b { font-family: var(--sans); font-weight: 700; color: var(--accent); }
@media (max-width: 600px) {
  .use, details.model { margin-left: 0; }
}

/* ---------- Tools row (self-test toggle) ---------- */
.tools { display: flex; flex-wrap: wrap; align-items: center; gap: 0.75rem 1rem; margin: 0 0 1rem; }
.toggle {
  appearance: none; cursor: pointer; font: 600 0.95rem var(--sans); color: var(--ink);
  background: var(--surface); border: 1.5px solid var(--ink); padding: 0.45rem 1rem; border-radius: 999px;
}
.toggle[aria-pressed="true"] { background: var(--ink); color: var(--paper); }
.tools .hint { font: 500 0.9rem var(--sans); color: var(--muted); }

[data-conceal] { transition: background 0.15s; }
.is-quiz [data-conceal]:not(.revealed) {
  color: transparent; background: var(--line); border-radius: 5px; cursor: pointer; user-select: none; text-shadow: none;
}
.is-quiz [data-conceal]:not(.revealed) * { color: transparent; }

/* ---------- Homophones ---------- */
.hgroup {
  display: grid; gap: 1rem 2.5rem; padding: 1.2rem 0; border-top: 1px solid var(--line);
  grid-template-columns: repeat(var(--n, 2), minmax(0, 1fr));
}
@media (max-width: 640px) { .hgroup { grid-template-columns: 1fr; gap: 0.9rem; } }
.hword .hw { font-size: 1.7rem; font-weight: 800; letter-spacing: -0.02em; margin: 0 0 0.2rem; display: flex; align-items: center; gap: 0.6rem; }
.hword p { margin: 0; font-size: 1rem; color: var(--muted); }
.hword .added { font: 500 0.8rem var(--sans); }

/* ---------- Opposites table ---------- */
.table-wrap { overflow-x: auto; }
table.opp { border-collapse: collapse; width: 100%; min-width: 520px; font-size: 1rem; }
table.opp th { font: 700 0.9rem var(--sans); text-align: left; padding: 0.6rem 0.75rem; border-bottom: 2px solid var(--ink); }
table.opp td { padding: 0.65rem 0.75rem; border-bottom: 1px solid var(--line); vertical-align: top; }
table.opp td:first-child { font: 700 1.05rem var(--sans); white-space: nowrap; }
table.opp td:last-child span { font: 700 1.05rem var(--sans); color: var(--accent); }

/* ---------- Word lists ---------- */
.chips { list-style: none; margin: 0.5rem 0 1.5rem; padding: 0; display: flex; flex-wrap: wrap; gap: 0.4rem; max-width: 760px; }
.chips li { max-width: none; }
.chips button {
  appearance: none; cursor: pointer; font: 500 0.95rem var(--sans); color: var(--ink);
  background: var(--surface); border: 1px solid var(--line); padding: 0.3rem 0.8rem; border-radius: 999px;
}
.chips button:hover { border-color: var(--accent); color: var(--accent); }
.chips .em button { background: var(--mark); border-color: transparent; font-weight: 700; }

/* ---------- Examples & grammar ---------- */
.eg { margin: 0.5rem 0 1.5rem; padding: 0.2rem 0 0.2rem 1.1rem; border-left: 4px solid var(--accent); list-style: none; }
.eg li { padding: 0.15rem 0; }
.eg b { font-family: var(--sans); font-weight: 700; color: var(--accent); }
.eg .gloss { display: block; font: 500 0.9rem var(--sans); color: var(--muted); }

.rule { background: var(--surface); border: 1px solid var(--line); border-radius: 8px; padding: 1rem 1.25rem; margin: 1rem 0 1.5rem; max-width: 68ch; }
.rule p:last-child { margin-bottom: 0; }

.contrast { margin: 0.5rem 0 1.75rem; display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 0.2rem 1rem; max-width: 720px; }
.contrast dt { font: 700 0.85rem var(--sans); color: var(--muted); padding-top: 0.25rem; }
.contrast dd { margin: 0; }
.contrast dd.to { margin-bottom: 0.9rem; font-weight: 600; }
.contrast dd.to::before { content: "\2192\00a0"; color: var(--accent); font-weight: 700; }

.pairs-2 { display: grid; gap: 1.5rem 3rem; grid-template-columns: 1fr; max-width: 760px; }
@media (min-width: 640px) { .pairs-2 { grid-template-columns: 1fr 1fr; } }
.pairs-2 h4, .pairs-2 h5 { margin-top: 0; }

/* ---------- Reading ---------- */
.reading { max-width: 66ch; font-size: 1.1rem; line-height: 1.8; }
.reading p { max-width: none; }
.source { font: 500 0.9rem var(--sans); color: var(--muted); }

/* ---------- Acronym ---------- */
.acronym { list-style: none; margin: 0 0 1.5rem; padding: 0; font: 800 clamp(1.6rem, 4vw, 2.2rem)/1.25 var(--sans); }
.acronym li { max-width: none; letter-spacing: -0.02em; }
.acronym b { color: var(--accent); }

/* ---------- Practice ---------- */
.practice-bar { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 0.75rem 1rem; margin: 1.5rem 0 0; }
.practice-bar .score { margin: 0; }
.quiz { max-width: 760px; }
.score { font: 700 1rem var(--sans); margin: 0 0 1rem; }
.q { border: 0; border-top: 1px solid var(--line); margin: 0; padding: 1rem 0 1.1rem; min-width: 0; }
.q legend { font-size: 1.1rem; padding: 0; float: left; width: 100%; margin-bottom: 0.7rem; line-height: 1.55; }
.q .opts { clear: both; display: flex; flex-wrap: wrap; gap: 0.5rem; }
.q .blank { display: inline-block; min-width: 4.5rem; border-bottom: 2px solid var(--ink); text-align: center; font: 700 1rem var(--sans); }
.q .blank.ok { color: var(--ok); border-color: var(--ok); }
.q .blank.bad { color: var(--bad); border-color: var(--bad); }
.opt {
  appearance: none; cursor: pointer; font: 600 1rem var(--sans); color: var(--ink);
  background: var(--surface); border: 1.5px solid var(--line); padding: 0.45rem 1rem; border-radius: 8px;
}
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt:disabled { cursor: default; }
.opt.right { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 16%, var(--surface)); }
.opt.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 14%, var(--surface)); }
.q .why { clear: both; margin: 0.7rem 0 0; font: 500 0.95rem var(--sans); color: var(--muted); }

details.check { border-top: 1px solid var(--line); padding: 1rem 0; max-width: 760px; }
details.check summary { cursor: pointer; list-style: none; }
details.check summary::-webkit-details-marker { display: none; }
details.check .prompt { font-size: 1.1rem; display: block; margin-bottom: 0.6rem; }
details.check .show { font: 700 0.95rem var(--sans); color: var(--accent); text-decoration: underline; text-underline-offset: 0.2em; }
details.check[open] .show { display: none; }
details.check .answer { margin: 0.4rem 0 0; font-weight: 600; }
details.check .answer::before { content: "\2192\00a0"; color: var(--accent); font-weight: 700; }
details.check .tip { font: 500 0.9rem var(--sans); color: var(--muted); margin: 0.3rem 0 0; }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--line); padding: 1.75rem 0 3rem; font: 500 0.9rem var(--sans); color: var(--muted); }
.site-footer p { margin: 0 0 0.4rem; max-width: 70ch; }

@media print {
  .toc, .say, .say-wide, .toggle, .tools, .to-top, .theme-btn, .hero-actions { display: none !important; }
  body { background: #fff; color: #000; }
}