:root {
  --bg: #ffffff;
  --ink: #111a20;
  --muted: #6b7780;
  --line: #eceef0;
  --soft: #f6f7f8;
  --blue: #426b85;
  --orange: #e76f51;
  --max: 1120px;
  --pad: clamp(20px, 5vw, 48px);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e1418;
    --ink: #eef2f4;
    --muted: #93a1aa;
    --line: #1f2a31;
    --soft: #151d22;
    --blue: #8fb3cb;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: 'Inter', 'IBM Plex Sans Thai', system-ui, -apple-system, 'Segoe UI', sans-serif;
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* lang.js: one language once it has run, both without JS */
.js.lang-th [data-lang="en"],
.js.lang-en [data-lang="th"] { display: none; }

a { color: inherit; }

.index {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0 0 18px;
}

/* nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 28px;
  max-width: var(--max);
  margin: 0 auto;
  padding: 18px var(--pad);
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--blue);
}

.brand span { color: var(--ink); }

.brand-mark { width: 30px; height: 30px; }

.nav .links { margin-left: auto; display: flex; gap: 24px; }

.nav .links a {
  text-decoration: none;
  font-size: 14px;
  color: var(--muted);
  transition: color 0.15s;
}

.nav .links a:hover { color: var(--ink); }

nav.lang { display: flex; gap: 2px; padding: 3px; border: 1px solid var(--line); border-radius: 999px; }

nav.lang button {
  border: 0;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 4px 10px;
  border-radius: 999px;
  cursor: pointer;
}

nav.lang button[aria-pressed="true"] { background: var(--ink); color: var(--bg); }

main { max-width: var(--max); margin: 0 auto; padding: 0 var(--pad); }

/* hero */
.hero { padding: clamp(64px, 12vw, 140px) 0 clamp(56px, 9vw, 110px); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 28px;
  font-size: 14px;
  color: var(--muted);
}

.dot, .pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--orange);
  display: inline-block;
  flex: none;
}

.hero h1 {
  margin: 0;
  font-size: clamp(44px, 8.4vw, 104px);
  line-height: 1.02;
  letter-spacing: -0.035em;
  font-weight: 700;
}

.hero h1 .period { color: var(--orange); }

.lead {
  max-width: 560px;
  margin: 32px 0 0;
  font-size: clamp(17px, 1.6vw, 20px);
  color: var(--muted);
}

/* tool */
.tool {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: clamp(32px, 5vw, 72px);
  align-items: center;
  padding: clamp(48px, 7vw, 88px) 0;
  border-top: 1px solid var(--line);
}

.tool-name { display: flex; align-items: center; gap: 14px; }

.tool-name img { border-radius: 11px; }

.tool h2 { margin: 0; font-size: 32px; letter-spacing: -0.02em; }

.tool-lead { margin: 14px 0 22px; font-size: 19px; }

.features { list-style: none; padding: 0; margin: 0 0 26px; }

.features li {
  position: relative;
  padding: 10px 0 10px 22px;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 15.5px;
}

.features li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 21px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--blue);
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  padding: 7px 14px;
  border-radius: 999px;
  background: var(--soft);
  font-size: 13.5px;
  color: var(--muted);
}

.pulse { animation: pulse 2.4s ease-in-out infinite; }

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(231, 111, 81, 0.45); }
  50% { box-shadow: 0 0 0 6px rgba(231, 111, 81, 0); }
}

@media (prefers-reduced-motion: reduce) { .pulse { animation: none; } }

.tool-links { display: flex; flex-wrap: wrap; gap: 6px 22px; margin: 22px 0 0; font-size: 14px; }

.tool-links a { color: var(--muted); text-decoration: none; }

.tool-links a:first-child, .tool-links a:nth-child(2) { color: var(--blue); font-weight: 600; }

.tool-links a:hover { color: var(--ink); }

.tool-shot {
  margin: 0;
  padding: clamp(10px, 1.4vw, 16px);
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 22px;
}

.tool-shot img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 12px;
  box-shadow: 0 1px 2px rgba(17, 26, 32, 0.06), 0 12px 36px rgba(17, 26, 32, 0.10);
}

.next {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin: 0;
  padding: 28px 0;
  border-top: 1px dashed var(--line);
  color: var(--muted);
}

.next .index { margin: 0; }

/* principles */
.principles {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 32px;
  padding: clamp(56px, 8vw, 96px) 0;
  border-top: 1px solid var(--line);
}

.principles .index { color: var(--orange); margin-bottom: 10px; }

.principles h3 { margin: 0 0 6px; font-size: 17px; letter-spacing: -0.01em; }

.principles p { margin: 0; color: var(--muted); font-size: 15px; }

/* contact */
.contact { padding: clamp(56px, 8vw, 96px) 0; border-top: 1px solid var(--line); }

.contact .label { margin: 0 0 14px; font-size: 14px; color: var(--muted); }

.mail {
  display: inline-block;
  font-size: clamp(26px, 4.6vw, 52px);
  font-weight: 600;
  letter-spacing: -0.03em;
  text-decoration: none;
  border-bottom: 2px solid var(--orange);
  line-height: 1.15;
  word-break: break-all;
}

.mail:hover { color: var(--blue); }

.muted { color: var(--muted); font-size: 15px; margin: 20px 0 0; }

footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: 28px var(--pad) 44px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 860px) {
  .tool { grid-template-columns: 1fr; }
  .principles { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 560px) {
  .nav { gap: 14px; }
  .nav .links { display: none; }
  nav.lang { margin-left: auto; }
  .principles { grid-template-columns: 1fr; gap: 26px; }
  footer { flex-direction: column; }
}