/* JSONViewer landing page — custom design system.
   Brand gradient #2D6CF6 -> #22B8C4. Syntax colors:
   key #30B0C7, string #E5484D, number #2D6CF6, punctuation gray. */

:root {
  /* Brand */
  --brand-1: #2D6CF6;
  --brand-2: #22B8C4;
  --grad: linear-gradient(120deg, #2D6CF6 0%, #22B8C4 100%);

  /* Syntax */
  --syn-key: #30B0C7;
  --syn-string: #E5484D;
  --syn-number: #2D6CF6;
  --syn-punct: #8A94A6;

  /* Light palette — custom slate/ink, not bootstrap */
  --bg: #F7F9FC;
  --bg-alt: #EEF2F8;
  --surface: #FFFFFF;
  --ink: #0E1726;
  --ink-soft: #44506880;
  --text: #2A3344;
  --muted: #5B6678;
  --line: #E2E8F1;
  --code-bg: #0E1726;
  --code-ink: #C9D4E4;

  --radius: 14px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 2px rgba(14,23,38,.06), 0 2px 8px rgba(14,23,38,.05);
  --shadow-md: 0 8px 30px rgba(14,23,38,.10);
  --shadow-lg: 0 24px 70px rgba(14,23,38,.18);

  --maxw: 1100px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
          "Liberation Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0B0F17;
    --bg-alt: #0F1622;
    --surface: #131B29;
    --ink: #F2F6FC;
    --text: #C7D0DE;
    --muted: #8A94A6;
    --line: #1E2A3C;
    --code-bg: #0A0E16;
    --code-ink: #C9D4E4;
    --shadow-sm: 0 1px 2px rgba(0,0,0,.4);
    --shadow-md: 0 8px 30px rgba(0,0,0,.5);
    --shadow-lg: 0 24px 70px rgba(0,0,0,.6);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }

a { color: var(--brand-1); text-decoration: none; }
a:hover { text-decoration: underline; }

.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--brand-1); color: #fff; padding: 10px 16px; border-radius: 8px; z-index: 100;
}
.skip-link:focus { left: 12px; top: 12px; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.container-narrow { max-width: 760px; }
.center { text-align: center; }

/* ---------- Header / nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav {
  max-width: var(--maxw); margin: 0 auto; padding: 12px 24px;
  display: flex; align-items: center; gap: 18px;
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 700; }
.brand:hover { text-decoration: none; }
.brand img { border-radius: 8px; }
.brand-name { font-size: 17px; letter-spacing: -.01em; }
.nav-links { display: flex; gap: 22px; margin-left: 14px; }
.nav-links a { color: var(--muted); font-size: 14px; font-weight: 500; }
.nav-links a:hover { color: var(--ink); text-decoration: none; }
.nav-actions { display: flex; align-items: center; gap: 12px; margin-left: auto; }

.lang-toggle {
  display: inline-flex; border: 1px solid var(--line); border-radius: 999px;
  overflow: hidden; background: var(--surface);
}
.lang-toggle button {
  border: 0; background: transparent; color: var(--muted);
  font: inherit; font-size: 13px; font-weight: 600; padding: 6px 12px; cursor: pointer;
}
.lang-toggle button[aria-pressed="true"] { background: var(--grad); color: #fff; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  font-weight: 600; font-size: 15px; padding: 12px 22px; border-radius: 12px;
  border: 1px solid transparent; cursor: pointer; transition: transform .08s ease, box-shadow .2s ease;
  white-space: nowrap;
}
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--grad); color: #fff; box-shadow: 0 6px 20px rgba(45,108,246,.32); }
.btn-primary:hover { box-shadow: 0 10px 28px rgba(45,108,246,.42); }
.btn-ghost {
  background: var(--surface); color: var(--ink); border-color: var(--line);
}
.btn-ghost:hover { border-color: var(--brand-1); color: var(--brand-1); }
.btn-sm { padding: 8px 16px; font-size: 14px; border-radius: 10px; }

/* ---------- Hero ---------- */
.hero { position: relative; padding: 92px 24px 72px; text-align: center; overflow: hidden; }
.hero::before {
  content: ""; position: absolute; inset: -40% 0 auto 0; height: 620px;
  background:
    radial-gradient(60% 70% at 30% 0%, rgba(45,108,246,.18), transparent 70%),
    radial-gradient(50% 60% at 80% 10%, rgba(34,184,196,.16), transparent 70%);
  z-index: -1;
}
.hero-inner { max-width: 820px; margin: 0 auto; }
.hero-icon { width: 120px; height: 120px; margin: 0 auto 22px; border-radius: 26px; box-shadow: var(--shadow-lg); }
.eyebrow {
  display: inline-block; font-size: 13px; font-weight: 600; letter-spacing: .02em;
  color: var(--brand-1); margin: 0 0 14px;
  padding: 5px 12px; border: 1px solid var(--line); border-radius: 999px; background: var(--surface);
}
.hero h1 {
  font-size: clamp(2.1rem, 5.2vw, 3.6rem); line-height: 1.08; letter-spacing: -.025em;
  color: var(--ink); margin: 0 0 18px; font-weight: 800;
}
.hero-sub { font-size: clamp(1.05rem, 2.2vw, 1.25rem); color: var(--muted); margin: 0 auto 30px; max-width: 620px; }
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.center-cta { margin-top: 26px; }
.hero-meta { margin-top: 20px; font-size: 13px; color: var(--muted); font-family: var(--mono); }

/* ---------- Sections ---------- */
.section { padding: 84px 0; }
.section-alt { background: var(--bg-alt); }
.section-eyebrow {
  font-size: 13px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
  color: var(--brand-2); margin: 0 0 12px;
}
.section-title {
  font-size: clamp(1.6rem, 3.4vw, 2.4rem); line-height: 1.15; letter-spacing: -.02em;
  color: var(--ink); margin: 0 0 16px; font-weight: 800; max-width: 720px;
}
.section-lead { font-size: 1.08rem; color: var(--muted); margin: 0 0 36px; max-width: 640px; }

/* ---------- Features ---------- */
.feature-list {
  display: grid; gap: 1px; background: var(--line);
  border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden;
  grid-template-columns: repeat(3, 1fr); margin-top: 8px;
}
.feature { background: var(--surface); padding: 30px 26px; }
.feature h3 {
  font-size: 1.12rem; color: var(--ink); margin: 0 0 8px; font-weight: 700; letter-spacing: -.01em;
  display: flex; align-items: center; gap: 8px;
}
.feature h3::before {
  content: ""; width: 9px; height: 9px; border-radius: 3px; background: var(--grad); flex: none;
}
.feature p { margin: 0; color: var(--muted); font-size: .96rem; }

/* ---------- App mockup ("screenshot") ---------- */
.app-mockup {
  margin-top: 14px; border-radius: var(--radius-lg); overflow: hidden;
  background: var(--code-bg); box-shadow: var(--shadow-lg);
  border: 1px solid rgba(255,255,255,.06);
}
.window-chrome {
  display: flex; align-items: center; gap: 8px; padding: 12px 16px;
  background: #1b2433; border-bottom: 1px solid rgba(255,255,255,.06);
}
@media (prefers-color-scheme: light) { .window-chrome { background: #20293a; } }
.dot { width: 12px; height: 12px; border-radius: 50%; }
.dot-red { background: #ff5f57; }
.dot-yellow { background: #febc2e; }
.dot-green { background: #28c840; }
.window-title {
  margin-left: 10px; color: #8A94A6; font-size: 13px; font-family: var(--mono);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.app-toolbar {
  display: flex; align-items: center; gap: 8px; padding: 10px 14px;
  background: #141c29; border-bottom: 1px solid rgba(255,255,255,.05); flex-wrap: wrap;
}
.tool-btn {
  font: inherit; font-size: 12.5px; font-weight: 600; color: #C9D4E4;
  background: #232f42; border: 1px solid rgba(255,255,255,.07); border-radius: 8px;
  padding: 6px 12px; cursor: default;
}
.tool-primary { background: var(--grad); color: #fff; border-color: transparent; }
.toolbar-spacer { flex: 1 1 auto; min-width: 8px; }
.indent-picker {
  display: inline-flex; border: 1px solid rgba(255,255,255,.1); border-radius: 8px; overflow: hidden;
}
.seg { font-size: 12px; color: #8A94A6; padding: 6px 10px; font-family: var(--mono); }
.seg-active { background: rgba(45,108,246,.25); color: #cfe0ff; }

.app-body { display: grid; grid-template-columns: 1.6fr 1fr; }
.code-pane {
  margin: 0; padding: 18px 18px 18px 8px; font-family: var(--mono); font-size: 13px; line-height: 1.7;
  color: var(--code-ink); overflow-x: auto; white-space: pre; tab-size: 2;
}
.code-pane .ln {
  display: inline-block; width: 26px; margin-right: 14px; text-align: right;
  color: #3c4a61; user-select: none;
}
.code-pane .k { color: var(--syn-key); }
.code-pane .s { color: var(--syn-string); }
.code-pane .n { color: var(--syn-number); }
.code-pane .p { color: var(--syn-punct); }

.tree-pane {
  border-left: 1px solid rgba(255,255,255,.06); padding: 18px 16px;
  font-family: var(--mono); font-size: 12.5px; color: var(--code-ink); background: rgba(255,255,255,.015);
}
.tree-row { display: flex; align-items: center; gap: 6px; padding: 3px 0; white-space: nowrap; }
.tree-row .tw { color: var(--brand-2); width: 12px; display: inline-block; }
.tree-row .k { color: var(--syn-key); }
.tree-row .s { color: var(--syn-string); }
.tree-row .n { color: var(--syn-number); }
.tree-row .p { color: var(--syn-punct); }
.indent-1 { padding-left: 22px; }
.indent-2 { padding-left: 44px; }

.transform-row {
  display: flex; flex-wrap: wrap; gap: 8px; padding: 14px;
  background: #10171f; border-top: 1px solid rgba(255,255,255,.05);
}
.xform {
  font-family: var(--mono); font-size: 11.5px; color: #C9D4E4;
  background: #1c2738; border: 1px solid rgba(255,255,255,.08); border-radius: 7px; padding: 5px 9px;
}

/* ---------- Demo ---------- */
.demo {
  display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 8px;
}
.demo-col { display: flex; flex-direction: column; min-width: 0; }
.demo-label { font-size: 13px; font-weight: 600; color: var(--muted); margin-bottom: 8px; }
#demo-input, .demo-output {
  font-family: var(--mono); font-size: 13px; line-height: 1.6;
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--surface); color: var(--text); padding: 16px; min-height: 230px;
}
#demo-input { resize: vertical; width: 100%; }
#demo-input:focus { outline: 2px solid var(--brand-1); outline-offset: 1px; border-color: var(--brand-1); }
.demo-output {
  margin: 0; white-space: pre-wrap; word-break: break-word; overflow: auto;
  background: var(--code-bg); color: var(--code-ink);
}
.demo-output.is-error { color: var(--syn-string); }
.demo-controls { display: flex; align-items: center; gap: 10px; margin-top: 12px; flex-wrap: wrap; }
.demo-indent-label { font-size: 13px; color: var(--muted); margin-left: 4px; }
#demo-indent {
  font: inherit; font-size: 14px; padding: 7px 10px; border-radius: 10px;
  border: 1px solid var(--line); background: var(--surface); color: var(--text);
}

/* ---------- Syntax grid ---------- */
.syntax-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.syntax-item {
  display: flex; flex-direction: column; gap: 6px; background: var(--surface);
  border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px;
}
.syntax-item code {
  font-family: var(--mono); font-size: 14px; color: var(--brand-1); font-weight: 600;
}
.syntax-item span { color: var(--muted); font-size: .92rem; }

/* ---------- FAQ ---------- */
.faq { margin-top: 8px; }
.faq-q {
  font-weight: 700; color: var(--ink); font-size: 1.08rem;
  border-top: 1px solid var(--line); padding: 22px 0 8px;
}
.faq-a { margin: 0 0 22px; color: var(--muted); }

/* ---------- CTA section ---------- */
.section-cta { background: var(--bg-alt); }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--line); padding: 40px 0; background: var(--surface); }
.footer-inner { display: flex; flex-direction: column; gap: 14px; align-items: center; text-align: center; }
.footer-brand { display: flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 700; }
.footer-brand img { border-radius: 7px; }
.footer-note { color: var(--muted); margin: 0; max-width: 460px; font-size: .95rem; }
.footer-links { display: flex; gap: 22px; }
.footer-links a { color: var(--muted); font-size: 14px; font-weight: 500; }

/* ---------- Responsive ---------- */
@media (max-width: 880px) {
  .feature-list { grid-template-columns: repeat(2, 1fr); }
  .app-body { grid-template-columns: 1fr; }
  .tree-pane { border-left: 0; border-top: 1px solid rgba(255,255,255,.06); }
  .demo { grid-template-columns: 1fr; }
  .syntax-grid { grid-template-columns: 1fr; }
  .nav-links { display: none; }
}

@media (max-width: 520px) {
  .feature-list { grid-template-columns: 1fr; }
  .section { padding: 56px 0; }
  .hero { padding: 64px 20px 52px; }
  .container { padding: 0 18px; }
  .nav { padding: 10px 16px; gap: 10px; }
  .btn { padding: 11px 18px; font-size: 14px; }
  .hero-cta .btn { width: 100%; }
}