/* Bitcoin Đà Nẵng - Base reset & typography */

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

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

/* Defense-in-depth against horizontal scroll: any stray wide element gets
   clipped instead of bleeding into a body-level scrollbar. `clip` (not
   `hidden`) avoids creating a scroll container so `position: sticky` on
   the nav keeps working. */
html, body { overflow-x: clip; }

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  max-width: 100vw;
}

iframe { max-width: 100%; }

/* Theme: dark - meetup homepage */
body.theme-dark {
  background: var(--color-black);
  color: var(--color-text-on-dark);
}

body.theme-dark a { color: var(--color-gold); }
body.theme-dark a:hover { color: var(--color-gold-light); }

/* Theme: light - education / pizza day pages */
body.theme-light {
  background: var(--color-white);
  color: #1f1a12;
}

body.theme-light a { color: var(--color-gold-dark); }
body.theme-light a:hover { color: #6e530f; }

/* Headings */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: 0.005em;
  margin: 0 0 0.6em;
}

h1 { font-size: clamp(2.5rem, 6vw, 4.25rem); }
h2 { font-size: clamp(1.8rem, 4vw, 2.6rem); }
h3 { font-size: clamp(1.3rem, 2.5vw, 1.6rem); }

p { margin: 0 0 1em; }

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

button { font-family: inherit; cursor: pointer; }

ul { padding-left: 1.2em; }

/* Utility */
.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gutter);
}