/* Longtai Pro Audio draft v3 — monochrome, drawing-sheet frame (hairlines + fixed band padding),
   thin Noto Sans TC, text-first homepage. No accent colour. */
:root {
  --bg: #f4f4f4;
  --sheet: #fbfbfb;
  --surface: #ededed;
  --ink: #161616;
  --muted: #5e5e5e;
  --faint: #8a8a8a;
  --accent: #161616;
  --accent-ink: #ffffff;
  --hair: rgba(0, 0, 0, 0.11);
  --hair-w: 0.75px;
  --line: var(--hair-w) solid var(--hair);

  --font-display: "Noto Sans TC", system-ui, sans-serif;
  --font-text: "Noto Sans TC", system-ui, sans-serif;
  --font-hand: "Architects Daughter", "Noto Sans TC", sans-serif;

  --step-small: 0.875rem;
  --step-body: 1.0625rem;               /* 17px, Chinese body never under 16px */
  --step-lead: clamp(1.125rem, 1.05rem + 0.35vw, 1.3125rem);
  --step-head: clamp(1.75rem, 1.35rem + 1.6vw, 2.625rem);
  --step-hero: clamp(2.25rem, 1.4rem + 3.6vw, 4.25rem);

  --pad-x: clamp(1rem, 3.5vw, 3rem);   /* fixed band padding, like a drawing border */
  --pad-y: clamp(3rem, 6vw, 5rem);
  --frame-max: 1280px;
  --radius: 0px;
}

html { overflow-x: clip; }
body { background: var(--bg); color: var(--ink); font-weight: 400; font-size: var(--step-body); line-height: 1.7; overflow-x: clip; }
h1, h2, h3 { font-weight: 300; letter-spacing: 0; }
p { max-width: 38em; }
p + p { margin-top: 0.8em; }
a { text-underline-offset: 0.25em; text-decoration-thickness: 0.06em; }

.skip { position: absolute; left: 1rem; top: -4rem; z-index: 10; padding: 0.5rem 1rem; background: var(--ink); color: #fff; }
.skip:focus { top: 1rem; }

/* ---------- the frame: one sheet with hairline borders ---------- */
.frame { max-width: var(--frame-max); margin-inline: auto; background: var(--sheet); border-inline: var(--line); min-height: 100svh; }
.band { padding: var(--pad-y) var(--pad-x); border-top: var(--line); }

/* ---------- header ---------- */
.top { display: flex; align-items: center; gap: 2rem; min-height: 72px; padding: 0 var(--pad-x); }
.wordmark { display: inline-flex; align-items: baseline; gap: 0.7rem; margin-right: auto; text-decoration: none; }
.wm-zh { font-size: 1.25rem; font-weight: 500; letter-spacing: 0.08em; }
.wm-en { font-family: var(--font-hand); font-size: 1rem; color: var(--muted); }
.top-nav { display: flex; gap: 1.75rem; }
.top-nav a, .foot-nav a { text-decoration: underline; text-decoration-color: transparent; transition: text-decoration-color var(--t-hover) ease; }
.top-nav a[aria-current] { text-decoration-color: currentColor; }

.lang { display: flex; align-items: center; gap: 0.4rem; color: var(--muted); }
.lang [aria-current] { color: var(--ink); font-weight: 500; }
.lang a { text-decoration: none; padding: 0.25rem 0; }
.lang-sep { color: var(--faint); }
@media (hover: hover) and (pointer: fine) {
  .top-nav a:hover, .foot-nav a:hover, .lang a:hover { text-decoration: underline; text-decoration-color: currentColor; color: var(--ink); }
}

/* ---------- controls ---------- */
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 0.75rem 1.5rem; margin-top: 2rem; max-width: none; }
.button {
  min-height: 3rem; padding: 0 1.5rem; font-weight: 500; letter-spacing: 0.02em;
  background: linear-gradient(#3e3e3e, #1c1c1c); color: #fff;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.14), inset 0 -1px 0 rgba(0,0,0,0.4), 0 1px 3px rgba(0,0,0,0.18);
}
@media (hover: hover) and (pointer: fine) { .button:hover { background: linear-gradient(#4a4a4a, #262626); } }
.text-link { color: var(--muted); text-decoration: underline; text-decoration-color: var(--hair); text-decoration-thickness: 1px; transition: color var(--t-hover) ease, text-decoration-color var(--t-hover) ease; overflow-wrap: anywhere; }
@media (hover: hover) and (pointer: fine) { .text-link:hover { color: var(--ink); text-decoration-color: currentColor; } }

/* ---------- type helpers ---------- */
.label { font-size: var(--step-small); letter-spacing: 0.12em; color: var(--faint); font-variant-numeric: tabular-nums; }
.head { font-size: var(--step-head); line-height: 1.3; }
.band-head { display: grid; gap: 0.75rem; margin-bottom: clamp(2rem, 4vw, 3rem); }
.band-foot { margin-top: 2rem; }

/* ---------- hero ---------- */
.hero { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: clamp(2rem, 4vw, 4rem); align-items: center; min-height: min(calc(100svh - 72px), 760px); }
.hero-title { font-size: clamp(2.25rem, 1rem + 2.9vw, 4rem); line-height: 1.25; word-break: keep-all; }
.hero-lead { margin-top: 1.5rem; font-size: var(--step-lead); line-height: 1.75; color: var(--muted); max-width: 28em; }

/* Hero slot: holds the drawing-sheets component (hero/). It sizes itself: A3 stage + caption row. */
.hero-slot { min-width: 0; width: 100%; }
.hero-sheets { --lt-paper: #ffffff; --lt-edge: var(--hair); --lt-font-ui: var(--font-text); }

/* ---------- split: label / title left, text right ---------- */
.split { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); column-gap: clamp(2rem, 4vw, 4rem); row-gap: 0.75rem; align-items: start; }
.split .label { grid-column: 1 / -1; }
.split .head { grid-column: 1; }
.split-body { grid-column: 2; padding-top: 0.35rem; }
.case-place { display: block; font-size: var(--step-lead); color: var(--muted); margin-top: 0.25rem; }

/* ---------- services: cells divided by hairlines; 3 columns (6 cards = 3x2), 4 columns while there are exactly 4 ---------- */
.svc-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); border-top: var(--line); border-left: var(--line); }
.svc { padding: 1.75rem 1.5rem 2rem; border-right: var(--line); border-bottom: var(--line); }
.svc h3 { font-size: var(--step-lead); font-weight: 500; margin-top: 1.25rem; line-height: 1.4; }
.svc p { margin-top: 0.5rem; color: var(--muted); }
.icon { width: 44px; height: 44px; fill: none; stroke: var(--ink); stroke-width: 1.25; stroke-linecap: round; stroke-linejoin: round; }
.icon .hatch { stroke: var(--faint); }

/* ---------- who: two framed cards ---------- */
.who-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0; border-top: var(--line); border-left: var(--line); }
.who-card { display: flex; flex-direction: column; padding: 2rem 1.75rem; border-right: var(--line); border-bottom: var(--line); text-decoration: none; transition: background-color var(--t-hover) ease; }
.who-card h3 { font-size: var(--step-lead); font-weight: 500; line-height: 1.4; }
.who-card p { margin-top: 0.75rem; color: var(--muted); }
.who-card .more { margin-top: auto; padding-top: 1.5rem; color: var(--ink); text-decoration: underline; text-decoration-color: var(--hair); text-underline-offset: 0.25em; }
@media (hover: hover) and (pointer: fine) {
  .who-card:hover { background: var(--bg); }
  .who-card:hover .more { text-decoration-color: currentColor; }
}

/* ---------- process: four numbered columns ---------- */
.steps { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border-top: var(--line); }
.steps li { padding: 1.5rem 1.5rem 0 0; }
.steps li + li { padding-left: 1.5rem; border-left: var(--line); }
.step-no { display: block; font-size: var(--step-small); letter-spacing: 0.12em; color: var(--faint); }
.steps h3 { margin-top: 0.75rem; font-size: var(--step-lead); font-weight: 500; line-height: 1.4; }
.steps p { margin-top: 0.5rem; color: var(--muted); }

/* ---------- contact ---------- */
.contact { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); column-gap: clamp(2rem, 4vw, 4rem); row-gap: 1.5rem; padding-block: calc(var(--pad-y) * 1.25); }
.contact-title { font-size: var(--step-head); line-height: 1.35; }
.contact-body { padding-top: 0.35rem; }
.contact-body .actions { margin-top: 1.5rem; }
.contact-meta { margin-top: 1.25rem; color: var(--faint); font-size: var(--step-small); }

/* ---------- footer: a drawing title block ---------- */
.foot { border-top: var(--line); padding: 2rem var(--pad-x) 2.25rem; display: grid; grid-template-columns: 1fr auto; gap: 1.5rem 2rem; align-items: end; font-size: var(--step-small); color: var(--muted); }
.foot-nav { display: flex; flex-wrap: wrap; gap: 0.5rem 1.5rem; grid-column: 1 / -1; font-size: var(--step-body); color: var(--ink); }
.titleblock { margin: 0; display: grid; grid-template-columns: repeat(4, auto); justify-content: start; border: var(--line); }
.titleblock div { padding: 0.6rem 1rem; }
.titleblock div + div { border-left: var(--line); }
.titleblock dt { font-size: 0.75rem; letter-spacing: 0.12em; color: var(--faint); }
.titleblock dd { margin: 0.15rem 0 0; color: var(--ink); overflow-wrap: anywhere; }
.titleblock a { text-decoration: none; }
.copyright { color: var(--faint); white-space: nowrap; }

@media (min-width: 64.0625em) {
  .svc-grid:has(> .svc:nth-child(4):last-child) { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

/* ---------- tablet ---------- */
@media (max-width: 64em) {
  .hero { grid-template-columns: 1fr; min-height: 0; }
  .hero-slot { order: -1; }
  .svc-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .steps li:nth-child(3) { padding-left: 0; border-left: 0; }
  .steps li:nth-child(n+3) { margin-top: 1.5rem; border-top: var(--line); }
  .titleblock { grid-template-columns: repeat(2, auto); }
  .titleblock div:nth-child(3) { border-left: 0; }
  .titleblock div:nth-child(n+3) { border-top: var(--line); }
}

/* ---------- phone ---------- */
@media (max-width: 40em) {
  .top { flex-wrap: wrap; gap: 0 1rem; padding-top: 0.75rem; }
  .wm-en { display: none; }
  .top-nav { order: 3; width: 100%; gap: 1.25rem; padding: 0.5rem 0 0.75rem; }
  .split, .contact { grid-template-columns: 1fr; }
  .split-body { grid-column: 1; padding-top: 0.75rem; }
  .svc-grid, .who-grid, .steps { grid-template-columns: 1fr; }
  .steps li, .steps li + li { padding: 1.25rem 0 0; border-left: 0; margin-top: 0; }
  .steps li + li { margin-top: 1.25rem; border-top: var(--line); }
  .svc { display: grid; grid-template-columns: 44px 1fr; column-gap: 1rem; padding: 1.25rem 1rem; }
  .svc .icon { grid-row: 1 / 3; width: 40px; height: 40px; }
  .svc h3 { margin-top: 0; }
  .who-card { padding: 1.5rem 1.25rem; }
  .foot { grid-template-columns: 1fr; }
  .titleblock { grid-template-columns: 1fr; }
  .titleblock div + div { border-left: 0; border-top: var(--line); }
}

/* ---------- English pages: Inter for Latin text (Noto Sans TC stays as fallback for any CJK) ---------- */
html:lang(en) {
  --font-display: "Inter Tight", "Inter", "Noto Sans TC", system-ui, sans-serif;
  --font-text: "Inter", "Noto Sans TC", system-ui, sans-serif;
}
html:lang(en) body { overflow-wrap: break-word; }
html:lang(en) :is(h1, h2, h3, .case-card-title, .hero-title, .page-title) { word-break: normal; hyphens: manual; }
html:lang(en) :is(h1, h2) { letter-spacing: -0.01em; }
/* en homepage headline: 2 lines on desktop ("The pro audio expert / the experts call."), balanced wrap on phones */
html:lang(en) .hero-title { font-size: clamp(2.125rem, 0.85rem + 2.35vw, 3.125rem); line-height: 1.15; text-wrap: balance; }
@media (max-width: 40em) { html:lang(en) .br-wide { display: none; } }
html:lang(en) .top-nav { flex-wrap: wrap; row-gap: 0.25rem; }
@media (max-width: 40em) {
  /* "Email service@longtaiproaudio.com" is wider than a phone: let it wrap */
  html:lang(en) .button { white-space: normal; text-align: center; overflow-wrap: anywhere; padding-block: 0.6rem; }
}

/* placeholder for copy still to come (homepage does not load pages.css) */
mark.tbd { background: #ebebeb; color: #666; outline: var(--hair-w) dashed rgba(0, 0, 0, 0.4); outline-offset: -1px; padding: 0.1em 0.45em; }