/* ============================================
   base.css — Reset + Element พื้นฐาน
   ============================================ */

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

* { margin: 0; padding: 0; }

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg);
  background-image: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* ทรานสิชันตอนสลับธีม */
  transition: background-color var(--transition), color var(--transition);
}

h1, h2, h3, h4 { line-height: 1.25; font-weight: 700; letter-spacing: -0.01em; }

a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-hover); }

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

/* --- focus ที่มองเห็นชัด (accessibility) --- */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* --- scrollbar theme-aware --- */
::-webkit-scrollbar { width: 11px; height: 11px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: var(--radius-full);
  border: 3px solid var(--bg);
}
::-webkit-scrollbar-thumb:hover { background: var(--text-faint); }

/* --- selection --- */
::selection { background: var(--accent-soft); color: var(--text); }

/* --- utility --- */
.text-muted { color: var(--text-muted); }
.text-faint { color: var(--text-faint); }
.text-center { text-align: center; }
.hidden { display: none !important; }
.mt-1 { margin-top: var(--space-1); } .mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); } .mt-4 { margin-top: var(--space-4); }
.mt-5 { margin-top: var(--space-5); } .mt-6 { margin-top: var(--space-6); }

/* --- spinner ใช้ตอน loading state --- */
.spinner {
  width: 18px; height: 18px;
  border: 2px solid currentColor;
  border-right-color: transparent;
  border-radius: 50%;
  display: inline-block;
  animation: spin 0.6s linear infinite;
  vertical-align: middle;
}
@keyframes spin { to { transform: rotate(360deg); } }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}