/* ============================================================
   Sriansh OS — base.css
   Reset, typography, layout primitives, a11y, boot.
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }

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

body {
  font-family: var(--font-sans);
  font-size: clamp(15px, 1.05vw, 17px);
  line-height: 1.6;
  color: var(--txt-0);
  background: var(--bg-0);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  overflow-x: hidden;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; cursor: pointer; background: none; border: none; }
input, textarea, select { font: inherit; color: inherit; }
ul, ol { list-style: none; padding: 0; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

h1, h2, h3, h4 { line-height: 1.15; font-weight: 600; letter-spacing: -0.02em; }
h1 { font-size: var(--fs-2xl); }
h2 { font-size: var(--fs-xl); }
h3 { font-size: var(--fs-lg); }
p { color: var(--txt-1); }
.mono { font-family: var(--font-mono); }
.muted { color: var(--txt-2); }
.accent-text {
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}

/* Layout primitives */
.container { width: 100%; max-width: var(--container); margin-inline: auto; padding-inline: var(--s-6); }
.section { padding-block: var(--section-y); position: relative; }
.prose { max-width: var(--prose); }
.stack > * + * { margin-top: var(--s-4); }
.grid { display: grid; gap: var(--s-6); }

/* Section heading */
.section__eyebrow {
  font-family: var(--font-mono); font-size: var(--fs-sm);
  color: var(--accent-2); letter-spacing: 0.08em; text-transform: uppercase;
  display: inline-flex; align-items: center; gap: var(--s-2);
}
.section__title { margin-top: var(--s-3); }
.section__lead { margin-top: var(--s-4); color: var(--txt-1); max-width: 60ch; }

/* Skip link */
.skip-link {
  position: absolute; left: var(--s-4); top: -60px; z-index: 200;
  background: var(--bg-2); color: var(--txt-0); padding: var(--s-2) var(--s-4);
  border: 1px solid var(--line-strong); border-radius: var(--r-sm); transition: top var(--dur-2) var(--ease-out);
}
.skip-link:focus { top: var(--s-4); }

/* Visually hidden */
.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;
}

/* Reveal-on-scroll (only when JS is active) */
.js .reveal { opacity: 0; transform: translateY(16px); transition: opacity var(--dur-3) var(--ease-out), transform var(--dur-3) var(--ease-out); transition-delay: calc(var(--i, 0) * 80ms); }
.js .reveal.is-visible { opacity: 1; transform: none; }

/* Boot screen */
#boot {
  position: fixed; inset: 0; z-index: 1000; background: var(--bg-0);
  display: grid; place-items: center; transition: opacity var(--dur-4) var(--ease-out);
}
#boot.is-done { opacity: 0; pointer-events: none; }
.boot__inner { width: min(420px, 80vw); text-align: center; }
.boot__logo { font-family: var(--font-mono); font-weight: 700; font-size: 1.4rem; letter-spacing: 0.05em; }
.boot__logo b { color: var(--accent); }
.boot__bar { height: 4px; border-radius: var(--r-pill); background: var(--bg-2); margin-top: var(--s-6); overflow: hidden; }
.boot__bar > i { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--accent), var(--accent-2)); border-radius: inherit; transition: width var(--dur-4) var(--ease-out); }
.boot__log { font-family: var(--font-mono); font-size: var(--fs-xs); color: var(--txt-2); margin-top: var(--s-4); min-height: 2.4em; text-align: left; }
.boot__skip { position: absolute; top: var(--s-4); right: var(--s-4); font-family: var(--font-mono); font-size: var(--fs-xs); color: var(--txt-2); border: 1px solid var(--line); padding: var(--s-2) var(--s-3); border-radius: var(--r-pill); }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}