/* =========================================================================
   Linda Wen Consulting UG — Design System
   Brand: green accent on white, black text, large clean typography.
   Change the whole site's accent by editing --green below.
   ========================================================================= */

:root {
  --green:        #3aa76d;   /* brand accent (brighter map green) */
  --green-dark:   #2c8557;   /* hover / emphasis */
  --green-tint:   #eaf6ef;   /* light section background */
  --green-tint-2: #f4fbf7;   /* even lighter */
  --ink:          #111111;   /* primary text (black) */
  --ink-soft:     #444b52;   /* secondary text */
  --line:         #e4e8ea;   /* borders */
  --white:        #ffffff;   /* always-white (e.g. text on green) */

  /* theme-aware surfaces (flip in dark mode) */
  --bg:         #ffffff;              /* page background */
  --surface:    #ffffff;             /* cards, inputs, bars */
  --header-bg:  rgba(255,255,255,.72);
  color-scheme: light;

  --maxw: 1160px;
  --radius: 12px;
  --shadow: 0 6px 24px rgba(17, 17, 17, .07);
  --shadow-lg: 0 14px 40px rgba(17, 17, 17, .12);

  /* spacing scale (4px base) — one rhythm for the whole site */
  --space-1: 4px;   --space-2: 8px;   --space-3: 12px;  --space-4: 16px;
  --space-5: 24px;  --space-6: 32px;  --space-7: 48px;  --space-8: 64px;
  --space-9: 80px;  --space-10: 96px;

  /* motion tokens (Emil Kowalski / animations.dev easing vocabulary) */
  --ease-out:    cubic-bezier(0.23, 1, 0.32, 1);   /* enter/exit — snappy, responsive */
  --ease-drawer: cubic-bezier(0.32, 0.72, 0, 1);   /* sheets / menus */

  --font: "Inter", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto,
          "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei",
          "Noto Sans SC", sans-serif;

  --step-hero: clamp(2.4rem, 5.5vw, 4rem);
  --step-h2:   clamp(1.75rem, 3.3vw, 2.5rem);
  --step-h3:   clamp(1.15rem, 1.6vw, 1.4rem);
  --step-body: clamp(1.02rem, 1.15vw, 1.16rem);
}

/* ---------- dark mode ----------
   Token overrides only — every surface/text colour is a variable, so the whole
   site re-themes from here. Applies automatically when the OS is in dark mode,
   or when the user forces it with the header toggle (data-theme="dark").
   A user who forces light (data-theme="light") opts out of the OS media query. */
:root[data-theme="dark"],
:root[data-theme="dark"] .site-footer {          /* footer already dark; keep it consistent */
  color-scheme: dark;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ink: #e9efeb;  --ink-soft: #a6b4ac;  --line: #26322c;
    --bg: #0e1512;   --surface: #16201b;   --header-bg: rgba(14,21,18,.72);
    --green: #43b87a; --green-dark: #5cc790;
    --green-tint: #16241d; --green-tint-2: #121c17;
    --shadow: 0 6px 24px rgba(0,0,0,.45); --shadow-lg: 0 14px 40px rgba(0,0,0,.55);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --ink: #e9efeb;  --ink-soft: #a6b4ac;  --line: #26322c;
  --bg: #0e1512;   --surface: #16201b;   --header-bg: rgba(14,21,18,.72);
  --green: #43b87a; --green-dark: #5cc790;
  --green-tint: #16241d; --green-tint-2: #121c17;
  --shadow: 0 6px 24px rgba(0,0,0,.45); --shadow-lg: 0 14px 40px rgba(0,0,0,.55);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: var(--step-body);
  line-height: 1.6;                   /* tighter, more refined body leading */
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-optical-sizing: auto;          /* Apple §15 — let the face adapt to size */
  letter-spacing: 0;                  /* body copy sits near 0 tracking */
}
img, svg { max-width: 100%; height: auto; display: block; }
a { color: var(--green-dark); text-decoration: none; }
a:hover { text-decoration: underline; }
/* Apple §15: tracking is size-specific — negative as text grows, leading tighter on
   large headings; small text keeps near-zero/positive tracking. Hierarchy is built from
   weight + size + leading as a set (§15), not size alone. */
h1, h2, h3, h4 { color: var(--ink); text-wrap: balance; }  /* avoid orphan words in titles */
h1, h2 { font-weight: 800; line-height: 1.1;  letter-spacing: -0.022em; }
h3, h4 { font-weight: 700; line-height: 1.2;  letter-spacing: -0.012em; }
p { margin: 0 0 1rem; color: var(--ink-soft); text-wrap: pretty; }  /* nicer line breaks */

/* §16 Craft + §14 a11y: a visible, on-brand focus ring for keyboard users only,
   branded text selection, and anchor targets that clear the sticky header. */
::selection { background: color-mix(in srgb, var(--green) 22%, #fff); color: var(--ink); }
:focus-visible { outline: 2px solid var(--green); outline-offset: 3px; border-radius: 6px; }
:focus:not(:focus-visible) { outline: none; }
:target { scroll-margin-top: 96px; }

/* ---------- layout helpers ---------- */
.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 var(--space-5); }
.section { padding: var(--space-9) 0; }
.section--tint { background: var(--green-tint); }
.section--tint-2 { background: var(--green-tint-2); }
.section-head { max-width: 780px; margin: 0 auto var(--space-7); text-align: center; }
.section-head h2 { font-size: var(--step-h2); margin: 0 0 12px; }
.section-head p { font-size: 1.08rem; }
.eyebrow {
  display: inline-block; color: var(--green-dark); font-weight: 700;
  letter-spacing: .12em; text-transform: uppercase; font-size: .82rem;
  margin-bottom: 12px;
}
.center { text-align: center; }

/* ---------- header ---------- */
/* Apple §12: translucent chrome with content scrolling underneath. No permanent hard
   divider — a soft scroll-edge shadow fades in only once content slides under it. */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--header-bg);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition: box-shadow .25s var(--ease-out), border-color .25s var(--ease-out),
              background .25s var(--ease-out);
}
.site-header.is-scrolled {
  border-bottom-color: var(--line);
  box-shadow: var(--shadow);   /* separates from busy content when scrolled (theme-aware) */
}
/* §14: if the user reduces transparency, make the material frosty/solid instead */
@media (prefers-reduced-transparency: reduce) {
  .site-header { background: var(--surface); backdrop-filter: none; -webkit-backdrop-filter: none; }
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 18px; padding: 14px 22px; max-width: var(--maxw); margin: 0 auto;
}
.brand { display: flex; flex-direction: column; line-height: 1.15; }
.brand a { color: var(--ink); text-decoration: none; }
.brand__name { font-size: clamp(1.15rem, 2.1vw, 1.55rem); font-weight: 800; letter-spacing: -.01em; }
.brand__name b { color: var(--green); }
.brand__sub { font-size: .82rem; color: var(--ink-soft); font-weight: 500; }

.header-right { display: flex; align-items: center; gap: 18px; }

/* language switcher */
.lang-switch { display: flex; gap: 2px; border: 1px solid var(--line); border-radius: 999px; padding: 3px; background: var(--surface); }
.lang-switch button {
  border: 0; background: transparent; cursor: pointer;
  font: inherit; font-size: .82rem; font-weight: 700; color: var(--ink-soft);
  padding: 5px 11px; border-radius: 999px; line-height: 1;
  transition: background .18s var(--ease-out), color .18s var(--ease-out);
}
.lang-switch button:hover { color: var(--ink); }
.lang-switch button.is-active { background: var(--green); color: #fff; }

/* dark-mode toggle */
.theme-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 38px; height: 38px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--surface); color: var(--ink);
  cursor: pointer;
  transition: background .18s var(--ease-out), color .18s var(--ease-out), border-color .18s var(--ease-out);
}
.theme-toggle:hover { border-color: var(--green); color: var(--green-dark); }
.theme-toggle svg { width: 18px; height: 18px; display: block; }

/* nav */
.nav-toggle {
  display: none; border: 1px solid var(--line); background: var(--surface); border-radius: 8px;
  width: 42px; height: 38px; cursor: pointer; align-items: center; justify-content: center;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  content: ""; display: block; width: 20px; height: 2px; background: var(--ink); position: relative;
}
.nav-toggle span::before { position: absolute; top: -6px; }
.nav-toggle span::after { position: absolute; top: 6px; }

.main-nav { background: var(--bg); border-bottom: 1px solid var(--line); }
.main-nav ul {
  list-style: none; margin: 0 auto; padding: 0 22px; max-width: var(--maxw);
  display: flex; gap: 6px; flex-wrap: wrap;
}
.main-nav a {
  display: inline-block; padding: 14px 14px; color: var(--ink); font-weight: 600;
  font-size: .98rem; border-bottom: 3px solid transparent; text-decoration: none;
  transition: color .18s var(--ease-out), border-color .18s var(--ease-out);
}
.main-nav a:hover { color: var(--green-dark); }
.main-nav a.is-current { color: var(--green-dark); border-bottom-color: var(--green); }

/* ---------- buttons ---------- */
.btn {
  display: inline-block; cursor: pointer; font: inherit; font-weight: 700;
  padding: 13px 26px; border-radius: 999px; border: 2px solid var(--green);
  background: var(--green); color: #fff; text-decoration: none;
  box-shadow: 0 1px 2px rgba(17,17,17,.10), 0 4px 14px rgba(58,167,109,.22);
  transition: background .15s var(--ease-out), border-color .15s var(--ease-out),
              box-shadow .15s var(--ease-out), transform .12s var(--ease-out);
}
.btn:hover { background: var(--green-dark); border-color: var(--green-dark); text-decoration: none;
  box-shadow: 0 2px 4px rgba(17,17,17,.12), 0 8px 22px rgba(58,167,109,.30); }
.btn:active { transform: scale(0.97); }   /* feedback on press — Apple §1 (respond on pointer-down) */
.btn--ghost { background: transparent; color: var(--green-dark); box-shadow: none; }
.btn--ghost:hover { background: var(--green); color: #fff; }

/* ---------- hero ---------- */
.hero { padding: var(--space-9) 0 var(--space-7); text-align: center; }
.hero h1 { font-size: var(--step-hero); margin: 0 0 10px; line-height: 1.02; letter-spacing: -.03em; }
.hero .tagline { font-size: clamp(1.15rem, 2vw, 1.55rem); color: var(--green-dark); font-weight: 700; letter-spacing: -.01em; margin: 0 0 10px; }
.hero .subtagline { font-size: clamp(1.05rem, 1.4vw, 1.2rem); color: var(--ink-soft); line-height: 1.5; max-width: 620px; margin: 0 auto 30px; }
.hero-map { max-width: 760px; margin: 30px auto 0; }
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-top: 8px; }

/* hero entrance on first paint — @starting-style needs no JS.
   Purpose: prevent a jarring instant appear on the landing view (seen occasionally). */
.hero h1,
.hero .tagline,
.hero .subtagline,
.hero .hero-cta,
.hero-map {
  transition: opacity .5s var(--ease-out), transform .5s var(--ease-out);
}
@starting-style {
  .hero h1,
  .hero .tagline,
  .hero .subtagline,
  .hero .hero-cta,
  .hero-map { opacity: 0; transform: translateY(10px); }
}
.hero .tagline    { transition-delay: .05s; }
.hero .subtagline { transition-delay: .10s; }
.hero .hero-cta   { transition-delay: .15s; }
.hero-map         { transition-delay: .20s; }

/* language switch: brief crossfade so translated text doesn't hard-cut (see main.js) */
main { transition: opacity .15s var(--ease-out); }
main.lang-swapping { opacity: 0; }

/* ---------- cards grid ---------- */
.grid { display: grid; gap: var(--space-5); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

.card {
  position: relative;
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: var(--space-6); box-shadow: var(--shadow);
  transition: transform .18s var(--ease-out);
}
/* larger shadow as a fade-in overlay — animating opacity is GPU-friendly, box-shadow is not */
.card::after {
  content: ""; position: absolute; inset: 0; border-radius: inherit;
  box-shadow: var(--shadow-lg); opacity: 0; pointer-events: none;
  transition: opacity .18s var(--ease-out);
}
/* only lift on devices with a real hover pointer — never sticks on touch */
@media (hover: hover) and (pointer: fine) {
  .card:hover { transform: translateY(-3px); }
  .card:hover::after { opacity: 1; }
}
.card h3 { font-size: var(--step-h3); margin: 0 0 10px; }
.card p { margin: 0; }
.card__num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 40px; height: 40px; border-radius: 10px; margin-bottom: 14px;
  background: var(--green-tint); color: var(--green-dark); font-weight: 800; font-size: 1.1rem;
}
.card__icon { font-size: 1.9rem; margin-bottom: 10px; }

/* value cards (vision/philosophy/mission/advantage) */
.value-card h3 { color: var(--green-dark); }
.value-card h3::before {   /* a small, deliberate accent instead of a heavy top bar */
  content: ""; display: block; width: 28px; height: 3px; border-radius: 2px;
  background: var(--green); margin-bottom: 12px;
}

/* ---------- solution table ---------- */
.table-wrap { overflow-x: auto; border-radius: var(--radius); box-shadow: var(--shadow); }
table.solutions { width: 100%; border-collapse: collapse; background: var(--surface); min-width: 640px; }
table.solutions th, table.solutions td { padding: 16px 18px; text-align: left; vertical-align: top; border-bottom: 1px solid var(--line); }
table.solutions thead th { background: var(--green); color: #fff; font-size: .98rem; }
table.solutions tbody tr:nth-child(even) { background: var(--green-tint-2); }
table.solutions .col-topic { font-weight: 700; color: var(--green-dark); white-space: nowrap; }
table.solutions .col-num { color: var(--green-dark); font-weight: 800; width: 46px; }

/* ---------- page hero (inner pages) ---------- */
.page-hero { background: var(--green-tint); padding: var(--space-8) 0; text-align: center; }
.page-hero h1 { font-size: var(--step-h2); margin: 0 0 10px; }
.page-hero p { max-width: 720px; margin: 0 auto; font-size: 1.06rem; }

/* ---------- resources list ---------- */
.res-list { display: grid; gap: 16px; grid-template-columns: repeat(2, 1fr); }
.res-item { display: flex; gap: 14px; align-items: flex-start; padding: 20px 22px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); }
.res-item .card__icon { margin: 0; }
.res-item h3 { margin: 0 0 4px; font-size: 1.12rem; }
.res-item p { margin: 0; font-size: .98rem; }

/* ---------- contact ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: start; }
.contact-info dl { margin: 0; display: grid; grid-template-columns: auto 1fr; gap: 10px 18px; }
.contact-info dt { font-weight: 700; color: var(--green-dark); }
.contact-info dd { margin: 0; color: var(--ink-soft); }
.field { margin-bottom: 18px; }
.field label { display: block; font-weight: 600; margin-bottom: 6px; font-size: .95rem; }
.field input, .field textarea {
  width: 100%; font: inherit; padding: 12px 14px; border: 1px solid var(--line);
  border-radius: 10px; background: var(--surface); color: var(--ink);
}
.field input:focus, .field textarea:focus { outline: 2px solid var(--green); border-color: var(--green); }
.form-note { font-size: .85rem; color: var(--ink-soft); }
.form-status { margin-top: 14px; font-weight: 600; }
.form-status.ok { color: var(--green-dark); }
.form-status.err { color: #c0392b; }

/* ---------- footer ---------- */
.site-footer { background: #0f1a14; color: #cdd8d1; padding: 48px 0 28px; margin-top: 20px; }
.site-footer a { color: #cdd8d1; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; }
.footer-grid h4 { color: #fff; margin: 0 0 12px; font-size: 1rem; }
.footer-grid ul { list-style: none; margin: 0; padding: 0; }
.footer-grid li { margin-bottom: 8px; }
.footer-brand .brand__name { color: #fff; }
.footer-brand .brand__name b { color: var(--green); }
.footer-brand p { color: #9fb0a6; margin-top: 10px; }
.footer-bottom { border-top: 1px solid #223026; margin-top: 34px; padding-top: 18px; font-size: .85rem; color: #8fa197; text-align: center; }

/* ---------- utilities ---------- */
.mt-0 { margin-top: 0; } .mb-0 { margin-bottom: 0; }
[hidden] { display: none !important; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; gap: 32px; }
}
@media (max-width: 720px) {
  .nav-toggle { display: inline-flex; }
  .main-nav ul { display: none; flex-direction: column; padding: 8px 22px 16px; }
  .main-nav.is-open ul { display: flex; }
  .main-nav a { padding: 12px 4px; border-bottom: 1px solid var(--line); }
  .main-nav a.is-current { border-bottom-color: var(--line); }
  .grid--2, .grid--3, .grid--4, .res-list { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .brand__sub { display: none; }
  .section { padding: var(--space-7) 0; }
}

/* ---------- reduced motion ----------
   Not "no feedback" — gentler feedback. Keep opacity/colour, drop movement. */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
  .card:hover { transform: none; }
  .btn:active { transform: none; }
  .hero h1, .hero .tagline, .hero .subtagline, .hero .hero-cta, .hero-map {
    transition: opacity .3s var(--ease-out);   /* fade only, no slide */
  }
  @starting-style {
    .hero h1, .hero .tagline, .hero .subtagline, .hero .hero-cta, .hero-map {
      transform: none;
    }
  }
}