/* Shared foundation: tokens, base, typography, layout, components, navigation.
   No build step or external font requests. */
:root {
  color-scheme: light;
  --color-brand: #19394a;
  --color-brand-hover: #102a38;
  --color-accent: #27665f;
  --color-text: #20333d;
  --color-text-muted: #53636b;
  --color-background: #fafaf7;
  --color-surface: #ffffff;
  --color-section: #eef2f0;
  --color-border: #cbd4d3;
  --color-control-border: #788990;
  --color-on-brand: #ffffff;
  --color-focus: #a44213;
  --color-success: #24593b;
  --color-success-bg: #edf5ef;
  --color-error: #982f2f;
  --color-error-bg: #fcf0ef;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
  --text-small: 0.875rem;
  --text-body: 1rem;
  --text-lead: clamp(1.125rem, 1.025rem + 0.5vw, 1.375rem);
  --text-h3: clamp(1.25rem, 1.1rem + 0.5vw, 1.5rem);
  --text-h2: clamp(1.75rem, 1.3rem + 1.5vw, 2.5rem);
  --text-h1: clamp(2.25rem, 1.5rem + 2.5vw, 3.5rem);
  --text-display: clamp(2.5rem, 1.5rem + 3.5vw, 4.5rem);
  --leading-body: 1.7;
  --leading-heading: 1.18;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;
  --section-space: clamp(3.5rem, 2rem + 5vw, 6.5rem);
  --gutter: clamp(1rem, 0.5rem + 2vw, 2rem);
  --container-wide: 74rem;
  --container-reading: 43rem;
  --radius-small: 0.25rem;
  --radius-card: 0.5rem;
  --shadow-header: 0 1px 0 var(--color-border);
  --transition-fast: 150ms ease;
  --touch-target: 2.75rem;
  /* Variables cannot set media-query conditions. Split layouts use 52rem;
     the global desktop navigation needs 60rem. Grids adapt intrinsically. */
}

/* Base */
*, *::before, *::after { box-sizing: border-box; }
body { margin: 0; background: var(--color-background); color: var(--color-text); font-family: var(--font-body); font-size: var(--text-body); line-height: var(--leading-body); overflow-wrap: anywhere; }
h1, h2, h3, h4, p, ul, ol, dl, figure { margin: 0; }
img { display: block; max-width: 100%; height: auto; }
button, input, select, textarea { font: inherit; }
a { color: var(--color-accent); text-underline-offset: 0.2em; text-decoration-thickness: 1px; }
a:hover { color: var(--color-brand); text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--color-focus); outline-offset: 4px; }
[hidden] { display: none !important; }
section[id] { scroll-margin-top: var(--space-5); }

/* Classes preview type sizes without introducing false semantic headings. */
h1, .h1, h2, .h2, h3, .h3, h4, .display { font-weight: 650; line-height: var(--leading-heading); text-wrap: balance; }
h1, .h1 { font-size: var(--text-h1); letter-spacing: -0.025em; }
h2, .h2 { font-size: var(--text-h2); letter-spacing: -0.02em; }
h3, .h3 { font-size: var(--text-h3); letter-spacing: -0.01em; }
h4 { font-size: var(--text-body); }
.display { font-size: var(--text-display); letter-spacing: -0.035em; }
.lead { font-size: var(--text-lead); max-width: 40ch; color: var(--color-text-muted); }
.small, .field-help, .field-error { font-size: var(--text-small); }
.label, label, legend { font-weight: 600; }
.eyebrow { color: var(--color-accent); font-size: var(--text-small); font-weight: 650; letter-spacing: 0.09em; text-transform: uppercase; }
.text-muted { color: var(--color-text-muted); }
:lang(zh) { line-height: 1.85; }
:lang(zh) :is(h1, h2, h3, h4, .h1, .h2, .h3, .display) { line-height: 1.4; letter-spacing: 0; }
:lang(zh).eyebrow, :lang(zh) .eyebrow { letter-spacing: 0.04em; }

/* Layout primitives. min(100%, …) prevents narrow-screen overflow. */
.container { width: min(var(--container-wide), calc(100% - var(--gutter) * 2)); margin-inline: auto; }
.reading-container { width: min(100%, var(--container-reading)); margin-inline: auto; }
.section { padding-block: var(--section-space); }
.section--alternate { background: var(--color-section); }
.section--bordered { border-block-start: 1px solid var(--color-border); }
.stack > * + * { margin-block-start: var(--space-4); }
.stack--large > * + * { margin-block-start: var(--space-7); }
.cluster { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-3); }
.split-layout { display: grid; gap: var(--space-7); align-items: start; }
.split-layout > *, .card-grid > * { min-width: 0; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 19rem), 1fr)); gap: var(--space-5); }
.section-heading { max-width: 48rem; }
.section-heading > * + * { margin-block-start: var(--space-3); }
.prose > * + * { margin-block-start: var(--space-4); }
.prose :is(ul, ol) { padding-inline-start: var(--space-5); }
.prose li + li { margin-block-start: var(--space-2); }
.content-block { align-self: center; }
.type-sample { border-block-start: 2px solid var(--color-border); padding-block-start: var(--space-5); }

/* Components */
.button { display: inline-flex; align-items: center; justify-content: center; gap: var(--space-3); min-height: var(--touch-target); padding: var(--space-3) var(--space-5); border: 1px solid transparent; border-radius: var(--radius-small); font-weight: 600; line-height: 1.4; text-align: center; text-decoration: none; cursor: pointer; transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast); }
.button--primary { background: var(--color-brand); color: var(--color-on-brand); }
.button--primary:hover { background: var(--color-brand-hover); color: var(--color-on-brand); }
.button--secondary { color: var(--color-brand); border-color: var(--color-control-border); background: transparent; }
.button--secondary:hover { background: var(--color-section); }
.button:disabled { background: var(--color-section); color: var(--color-text-muted); border-color: var(--color-border); cursor: not-allowed; }
.text-link { display: inline-flex; gap: var(--space-3); align-items: center; min-height: var(--touch-target); font-weight: 600; }
.card { padding: clamp(1.25rem, 1rem + 1vw, 2rem); background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-card); }
.card .text-link { margin-block-start: var(--space-5); }
.badge { display: inline-block; width: fit-content; padding: var(--space-1) var(--space-3); border: 1px solid var(--color-border); border-radius: var(--radius-small); background: var(--color-section); color: var(--color-accent); font-size: var(--text-small); font-weight: 600; }
.badge--neutral { color: var(--color-text-muted); background: var(--color-background); }
.callout { padding: clamp(1.25rem, 1rem + 1vw, 2rem); border-inline-start: 3px solid var(--color-accent); background: var(--color-section); border-radius: var(--radius-small); }
.section--alternate .callout { background: var(--color-surface); }
.reference-list > div { display: grid; gap: var(--space-1); padding-block: var(--space-3); border-block-start: 1px solid var(--color-border); }
.reference-list dt { font-size: var(--text-small); color: var(--color-text-muted); }
.reference-list dd { margin: 0; font-weight: 600; }
.media-frame { overflow: hidden; aspect-ratio: 4 / 3; border: 1px solid var(--color-border); border-radius: var(--radius-card); background: var(--color-section); }
.media-frame img { width: 100%; height: 100%; object-fit: cover; }
.breadcrumbs ol { display: flex; flex-wrap: wrap; gap: var(--space-3); list-style: none; padding: 0; font-size: var(--text-small); }
.breadcrumbs li + li::before { content: "/"; margin-inline-end: var(--space-3); color: var(--color-text-muted); }
.breadcrumbs :is(a, span) { display: inline-flex; align-items: center; min-height: var(--touch-target); }
.form-panel { min-width: 0; margin: 0; padding: var(--space-5); border: 1px solid var(--color-border); border-radius: var(--radius-card); background: var(--color-surface); }
.form-panel legend { padding-inline: var(--space-2); }
.field { display: grid; gap: var(--space-2); }
.field :is(input, textarea, select) { min-width: 0; width: 100%; min-height: var(--touch-target); padding: var(--space-3); border: 1px solid var(--color-control-border); border-radius: var(--radius-small); background: var(--color-surface); color: var(--color-text); }
.field textarea { resize: vertical; }
.field input::placeholder, .field textarea::placeholder { color: var(--color-text-muted); opacity: 1; }
.field [aria-invalid="true"] { border: 2px solid var(--color-error); }
.field-help { color: var(--color-text-muted); }
.field-error { color: var(--color-error); }
.check-field { display: flex; align-items: start; gap: var(--space-3); min-height: var(--touch-target); padding-block: var(--space-2); font-weight: 400; cursor: pointer; }
.check-field input { flex: 0 0 auto; width: 1.25rem; height: 1.25rem; margin: var(--space-1) 0 0; accent-color: var(--color-brand); }
.notice { padding: var(--space-5); border: 1px solid; border-inline-start-width: 3px; border-radius: var(--radius-small); }
.notice--error { color: var(--color-error); background: var(--color-error-bg); }
.notice--success { color: var(--color-success); background: var(--color-success-bg); }

/* Without JS, mobile navigation stays expanded and usable. */
.site-header { background: var(--color-surface); box-shadow: var(--shadow-header); }
.header-inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--space-4); padding-block: var(--space-5); }
/* Approved SVG proportions; HTML dimensions reserve space, CSS sizes display. */
.brand { display: inline-flex; align-items: center; flex: 0 0 auto; min-height: var(--touch-target); text-decoration: none; }
.brand img { width: 11.25rem; height: auto; }
.brand--footer img { width: 7.5rem; }
.site-nav { display: flex; flex-direction: column; align-items: stretch; gap: var(--space-2); width: 100%; }
.site-nav > a:not(.button) { display: flex; align-items: center; min-height: var(--touch-target); padding: var(--space-2) var(--space-3); color: var(--color-text); font-size: var(--text-small); font-weight: 600; text-decoration: none; }
.site-nav > a:not(.button):hover { color: var(--color-accent); text-decoration: underline; }
.header-inner[data-menu-ready] .site-nav { display: none; }
.header-inner[data-menu-ready][data-menu-open] .site-nav { display: flex; }
.site-footer { border-block-start: 1px solid var(--color-border); padding-block: var(--space-6); }
.footer-inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--space-5); }
.site-footer a { display: inline-flex; align-items: center; min-height: var(--touch-target); }
.skip-link { position: absolute; z-index: 10; inset-block-start: var(--space-3); inset-inline-start: var(--space-3); padding: var(--space-3) var(--space-4); background: var(--color-surface); border: 2px solid var(--color-brand); transform: translateY(-200%); }
.skip-link:focus { transform: translateY(0); }

/* Keep the approved full logo on every screen; leave room for Menu at 320px. */
.site-header .brand img { width: clamp(10.5rem, 52vw, 11.25rem); }
@media (min-width: 52rem) {
  .split-layout { grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr); gap: var(--space-8); }
  .intro .split-layout { align-items: center; }
}
@media (min-width: 60rem) {
  .menu-toggle { display: none; }
  .site-nav, .header-inner[data-menu-ready] .site-nav { display: flex; width: auto; flex-direction: row; flex-wrap: wrap; align-items: center; }
}

/* Global shell and homepage. Reuse Phase 1 colors, spacing, and components. */
.language-control { display: grid; justify-items: start; padding-block-end: var(--space-3); border-block-end: 1px solid var(--color-border); }
.language-options { display: flex; align-items: center; gap: var(--space-2); }
.language-options :is(a, button) { display: inline-flex; align-items: center; justify-content: center; min-width: var(--touch-target); min-height: var(--touch-target); padding: var(--space-2); font-size: var(--text-small); font-weight: 600; }
.language-options a { color: var(--color-text); }
.language-options a[aria-current="true"] { color: var(--color-accent); text-decoration-thickness: 2px; font-weight: 700; background: var(--color-section); border-radius: var(--radius-small); }
.site-nav > a[aria-current="page"] { color: var(--color-accent); text-decoration: underline; }
.site-nav > .button[aria-current="page"] { color: var(--color-on-brand); }
.audience-panel { padding-inline-start: var(--space-5); border-inline-start: 2px solid var(--color-border); }
.audience-path + .audience-path { margin-block-start: var(--space-6); padding-block-start: var(--space-6); border-block-start: 1px solid var(--color-border); }
.founder-roles { border-block-start: 1px solid var(--color-border); }
.founder-roles > div { padding-block: var(--space-5); border-block-end: 1px solid var(--color-border); }
.founder-roles dd { margin-inline-start: 0; }
.review-checklist { padding-inline-start: var(--space-5); }
.review-checklist li + li { margin-block-start: var(--space-3); }
.conversion-block { max-width: 52rem; }
.conversion-block .lead { max-width: 55ch; }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 14rem), 1fr)); gap: var(--space-7); }
.footer-grid > * { min-width: 0; }
.footer-grid .label { font-size: var(--text-small); line-height: var(--leading-body); letter-spacing: 0; }
.footer-brand { max-width: 20rem; }
.footer-nav { display: grid; justify-items: start; align-content: start; }
.footer-nav a { font-size: var(--text-small); }
.footer-bottom { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: var(--space-4); margin-block-start: var(--space-6); padding-block-start: var(--space-4); border-block-start: 1px solid var(--color-border); }
.footer-bottom a { font-size: var(--text-small); }
@media (min-width: 60rem) {
  .language-control { order: 1; padding-block-end: 0; padding-inline-start: var(--space-3); border-block-end: 0; border-inline-start: 1px solid var(--color-border); }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}
@media (forced-colors: active) {
  .button, .card, .callout, .notice { border: 1px solid CanvasText; }
  :focus-visible { outline-color: Highlight; }
}

/* Phase 3 interior pages use the existing foundation and shell. */
.page-intro h1 { max-width: 23ch; }
.page-intro .lead { max-width: 60ch; }
.reading-copy { max-width: var(--container-reading); }
.service-row { padding-block: var(--space-6); border-block-start: 1px solid var(--color-border); }
.service-row:first-child { padding-block-start: 0; border: 0; }
.service-row h3 { max-width: 27ch; }
.process-list { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr)); gap: var(--space-7); padding-inline-start: var(--space-5); }
.process-list li { padding-inline-start: var(--space-2); }
.process-list li::marker { color: var(--color-accent); font-weight: 650; }
.founder-grid, .form-layout { display: grid; gap: var(--space-7); }
.founder-grid > *, .form-layout > * { min-width: 0; }
.photo-placeholder { display: flex; flex-direction: column; justify-content: center; align-items: center; gap: var(--space-5); aspect-ratio: 4 / 3; padding: var(--space-5); background: var(--color-section); border: 1px solid var(--color-border); border-radius: var(--radius-card); }
.portrait-initial { color: var(--color-accent); font-size: var(--text-display); font-weight: 650; }
.photo-placeholder figcaption { color: var(--color-text-muted); font-size: var(--text-small); text-align: center; }
.form-panel { padding: clamp(1rem, 0.5rem + 2vw, 2rem); }
[data-error-summary] a { color: inherit; }
@media (min-width: 52rem) {
  .founder-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-8); }
  .form-layout { grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr); gap: var(--space-8); }
}

/* Traditional Chinese uses installed Taiwan fonts; no web-font downloads. */
:root:lang(zh-Hant) { --font-body: "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; }
body:lang(zh-Hant) { line-break: strict; }

/* Phase 6 static content uses the existing design tokens and reading measure. */
.content-detail h1 { max-width: 26ch; }
.content-detail .lead { max-width: 60ch; }
.content-meta { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 12rem), 1fr)); gap: var(--space-4); padding-block: var(--space-5); border-block: 1px solid var(--color-border); }
.content-meta dt { font-size: var(--text-small); color: var(--color-text-muted); }
.content-meta dd { margin: 0; font-weight: 600; }
.content-body > section { scroll-margin-top: var(--space-5); }
.content-body h2 { font-size: var(--text-h3); }
.content-body h3 { font-size: 1.125rem; }
.content-body :is(ul, ol) { padding-inline-start: var(--space-5); }
.content-body li + li { margin-block-start: var(--space-2); }
.content-body blockquote { margin-inline: 0; padding-inline-start: var(--space-5); border-inline-start: 3px solid var(--color-accent); }
.content-card h3 a { color: var(--color-brand); text-decoration-thickness: 1px; display: inline-block; padding-block: var(--space-2); }
.content-card p { max-width: 65ch; }
.content-figure { display: grid; gap: var(--space-3); }
.content-figure img { width: 100%; border: 1px solid var(--color-border); border-radius: var(--radius-small); }
.content-figure figcaption { color: var(--color-text-muted); font-size: var(--text-small); }
.table-scroll { max-width: 100%; overflow-x: auto; border: 1px solid var(--color-control-border); border-radius: var(--radius-small); }
.table-scroll table { width: 100%; min-width: 36rem; border-collapse: collapse; text-align: start; }
.table-scroll caption { padding: var(--space-4); text-align: start; font-weight: 600; background: var(--color-section); }
.table-scroll :is(th, td) { padding: var(--space-4); vertical-align: top; border-block-start: 1px solid var(--color-border); }
.table-scroll th { font-weight: 600; }
.table-scroll thead { background: var(--color-section); }
.language-fallback-note { max-width: 24ch; font-size: var(--text-small); color: var(--color-text-muted); }
@media print {
  .content-detail .table-scroll { overflow: visible; }
  .content-detail .table-scroll table { min-width: 0; }
}