/* ============================================================
   Base Styles — Reset + Typography + Layout
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Noto+Sans+Thai:wght@400;500;600;700&display=swap');

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-normal);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding-top: var(--topbar-height);
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-bold);
  line-height: var(--leading-tight);
  color: var(--color-text);
}

h1 { font-size: clamp(var(--text-4xl), 6vw, var(--text-7xl)); }
h2 { font-size: clamp(var(--text-3xl), 4vw, var(--text-5xl)); }
h3 { font-size: clamp(var(--text-2xl), 3vw, var(--text-3xl)); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p { line-height: var(--leading-normal); }

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition-fast);
}
a:hover { color: var(--color-primary-dark); }

img, video {
  max-width: 100%;
  height: auto;
  display: block;
}

ul, ol { list-style: none; }

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

/* --- Container --- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

/* --- Section spacing --- */
.section {
  padding-block: var(--space-20);
}
.section--sm { padding-block: var(--space-12); }
.section--lg { padding-block: var(--space-32); }

/* --- Section header --- */
.section-label {
  display: inline-block;
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--color-primary);
  background: var(--color-primary-light);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: var(--space-4);
}

.section-title {
  font-size: clamp(var(--text-3xl), 4vw, var(--text-5xl));
  font-weight: var(--font-bold);
  color: var(--color-text);
  margin-bottom: var(--space-4);
  line-height: var(--leading-tight);
}

.section-desc {
  font-size: var(--text-lg);
  color: var(--color-muted);
  max-width: 600px;
  line-height: var(--leading-loose);
}

.section-header {
  margin-bottom: var(--space-12);
}
.section-header--center {
  text-align: center;
}
.section-header--center .section-desc {
  margin-inline: auto;
}

/* --- Grid --- */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-6); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-6); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-6); }

@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .section { padding-block: var(--space-12); }
  .section-header { margin-bottom: var(--space-8); }
}

/* --- Utilities --- */
.text-primary   { color: var(--color-primary); }
.text-muted     { color: var(--color-muted); }
.text-center    { text-align: center; }
.font-semibold  { font-weight: var(--font-semibold); }
.font-bold      { font-weight: var(--font-bold); }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); border: 0;
}

/* --- Scroll reveal animation --- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }
.reveal-delay-5 { transition-delay: 0.5s; }