/* Reset, typography, layout primitives, header, footer, buttons. */
*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 1rem);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: var(--step-0);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s var(--ease), color 0.3s var(--ease);
}

h1, h2, h3 { margin: 0; line-height: 1.2; font-weight: 700; letter-spacing: -0.01em; }
:lang(en) h1, :lang(en) h2 { letter-spacing: -0.03em; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }

::selection { background: var(--accent); color: var(--accent-ink); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.container {
  width: min(100% - 2.5rem, var(--container));
  margin-inline: auto;
}

.mono { font-family: var(--font-mono); font-size: var(--step--1); letter-spacing: 0.01em; }
:lang(ar) .mono { letter-spacing: 0; font-size: calc(var(--step--1) * 1.08); }
.muted { color: var(--muted); }
.accent { color: var(--accent); }

.kicker { color: var(--muted); margin-block-end: var(--space-3); }

.skip-link {
  position: absolute;
  inset-inline-start: 1rem;
  top: -100px;
  z-index: 100;
  padding: var(--space-2) var(--space-3);
  background: var(--accent);
  color: var(--accent-ink);
  border-radius: var(--radius-sm);
}
.skip-link:focus { top: 1rem; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  background: var(--header-bg);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-block-end: 1px solid var(--border);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.logo {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 1rem;
  direction: ltr;
}
.logo-bracket { color: var(--accent); }

.nav { display: flex; gap: var(--space-4); }
.nav a {
  position: relative;
  color: var(--muted);
  font-size: var(--step--1);
  transition: color 0.2s;
}
.nav a::after {
  content: "";
  position: absolute;
  inset-inline: 0;
  bottom: -4px;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transition: transform 0.3s var(--ease);
}
.nav a:hover { color: var(--text); }
.nav a:hover::after { transform: scaleX(1); }

.header-actions { display: flex; gap: var(--space-2); }

.icon-btn {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: transparent;
  cursor: pointer;
  transition: border-color 0.2s, background-color 0.2s;
}
.icon-btn:hover { border-color: var(--accent); }
.icon-btn svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
}
.lang-btn { font-family: var(--font-sans); font-weight: 600; font-size: 0.9rem; }

[data-theme="dark"] .icon-moon,
[data-theme="light"] .icon-sun { display: none; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.8rem 1.4rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s var(--ease), background-color 0.2s, border-color 0.2s;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: var(--accent); color: var(--accent-ink); }
.btn-ghost { border-color: var(--border); background: transparent; }
.btn-ghost:hover { border-color: var(--text); }
.btn-sm { padding: 0.45rem 1rem; font-size: var(--step--1); }

/* ---------- Footer ---------- */
.site-footer {
  border-block-start: 1px solid var(--border);
  padding-block: var(--space-5);
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-3);
}

/* ---------- Reveal on scroll ---------- */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.is-visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
  .reveal { opacity: 1; transform: none; }
}

@media (max-width: 720px) {
  .nav { display: none; }
}