/* ============================================================
   Hamza Hassanain — personal site
   Tokens: light by default, dark via prefers-color-scheme or [data-theme]
   ============================================================ */
:root {
  --bg: #fafaf9;
  --bg-elev: #ffffff;
  --bg-sunk: #f2f1ee;
  --text: #16181d;
  --text-2: #4a4f5a;
  --text-3: #6f7480;
  --border: #e4e2dd;
  --accent: #c2600a;
  --accent-strong: #a14f06;
  --accent-soft: #fdf0e1;
  --on-accent: #ffffff;
  --yc: #f26522;
  --shadow: 0 1px 2px rgba(16, 18, 24, .04), 0 4px 16px rgba(16, 18, 24, .05);
  --radius: 14px;
  --maxw: 1120px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0b0d10;
    --bg-elev: #12151a;
    --bg-sunk: #0f1215;
    --text: #e8e9ec;
    --text-2: #b3b7c0;
    --text-3: #8a8f9a;
    --border: #232830;
    --accent: #f59e0b;
    --accent-strong: #fbbf24;
    --accent-soft: rgba(245, 158, 11, .12);
    --on-accent: #111111;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px rgba(0, 0, 0, .25);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0b0d10;
  --bg-elev: #12151a;
  --bg-sunk: #0f1215;
  --text: #e8e9ec;
  --text-2: #b3b7c0;
  --text-3: #8a8f9a;
  --border: #232830;
  --accent: #f59e0b;
  --accent-strong: #fbbf24;
  --accent-soft: rgba(245, 158, 11, .12);
  --on-accent: #111111;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px rgba(0, 0, 0, .25);
  color-scheme: dark;
}

/* ---------- Base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 400 16px/1.65 var(--font);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; text-underline-offset: 3px; }
a:hover { text-decoration: underline; color: var(--accent-strong); }
code { font: 500 .86em var(--mono); background: var(--bg-sunk); border: 1px solid var(--border); padding: .08em .35em; border-radius: 6px; word-break: break-word; }
strong { font-weight: 650; color: var(--text); }
h1, h2, h3, h4 { line-height: 1.25; margin: 0; letter-spacing: -.01em; }
.mono { font-family: var(--mono); }
.meta { color: var(--text-3); font-size: .9rem; margin: .25rem 0 0; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 6px; }

.skip { position: absolute; left: -999px; top: 8px; background: var(--accent); color: var(--on-accent); padding: .5rem 1rem; border-radius: 8px; z-index: 100; }
.skip:focus { left: 16px; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 16px; }
@media (min-width: 720px) { .container { padding: 0 32px; } }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav__inner { max-width: var(--maxw); margin: 0 auto; padding: 0 16px; height: 60px; display: flex; align-items: center; gap: 1rem; }
@media (min-width: 720px) { .nav__inner { padding: 0 32px; } }
.nav__brand { font-weight: 700; color: var(--text); font-size: 1.05rem; }
.nav__brand .mono { color: var(--accent); }
.nav__brand:hover { text-decoration: none; color: var(--text); }
.nav__links { display: flex; gap: .15rem; margin-left: auto; }
.nav__links a { color: var(--text-2); font-size: .88rem; font-weight: 500; padding: .4rem .6rem; border-radius: 8px; }
.nav__links a:hover, .nav__links a.active { color: var(--text); background: var(--bg-sunk); text-decoration: none; }
.nav__actions { display: flex; gap: .4rem; }
.icon-btn {
  display: inline-grid; place-items: center; width: 38px; height: 38px;
  border: 1px solid var(--border); border-radius: 10px; background: var(--bg-elev);
  color: var(--text-2); cursor: pointer;
}
.icon-btn:hover { color: var(--text); border-color: var(--text-3); }
.nav__menu { display: none; }
.i-moon { display: none; }
:root[data-theme="dark"] .i-sun { display: none; }
:root[data-theme="dark"] .i-moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .i-sun { display: none; }
  :root:not([data-theme="light"]) .i-moon { display: block; }
}

@media (max-width: 1020px) {
  .nav__menu { display: inline-grid; }
  .nav__actions { margin-left: auto; }
  .nav__links {
    display: none; position: absolute; top: 60px; left: 0; right: 0;
    flex-direction: column; gap: 0; padding: .5rem 16px 1rem;
    background: var(--bg); border-bottom: 1px solid var(--border); box-shadow: var(--shadow);
  }
  .nav__links.open { display: flex; }
  .nav__links a { padding: .7rem .5rem; font-size: 1rem; }
}

/* ---------- Buttons, badges, tags ---------- */
.btn {
  display: inline-flex; align-items: center; gap: .5rem;
  padding: .7rem 1.1rem; border-radius: 10px; font-weight: 600; font-size: .95rem;
  border: 1px solid var(--border); background: var(--bg-elev); color: var(--text);
  transition: transform .15s ease, border-color .15s ease, background .15s ease;
}
.btn:hover { text-decoration: none; color: var(--text); border-color: var(--text-3); transform: translateY(-1px); }
.btn--primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn--primary:hover { background: var(--accent-strong); border-color: var(--accent-strong); color: var(--on-accent); }
.btn--sm { padding: .45rem .8rem; font-size: .85rem; margin-top: .75rem; }
.btn--lg { padding: .9rem 1.4rem; font-size: 1.05rem; word-break: break-all; }

.badge { display: inline-block; font: 700 .72rem/1 var(--font); padding: .32rem .5rem; border-radius: 6px; vertical-align: middle; letter-spacing: .02em; }
.badge--yc { background: var(--yc); color: #fff; }

.tags { list-style: none; display: flex; flex-wrap: wrap; gap: .4rem; padding: 0; margin: 1rem 0 0; }
.tags li { font: 500 .78rem/1 var(--mono); padding: .4rem .55rem; border-radius: 7px; background: var(--bg-sunk); color: var(--text-2); border: 1px solid var(--border); }
.pill { display: inline-block; font: 600 .7rem/1 var(--mono); padding: .25rem .4rem; border-radius: 5px; background: var(--accent-soft); color: var(--accent); margin-right: .35rem; }

/* Brand icons via CSS masks so they follow currentColor */
.si { display: inline-block; width: 18px; height: 18px; flex: none; background: currentColor; -webkit-mask: var(--icon) center / contain no-repeat; mask: var(--icon) center / contain no-repeat; }
.si--brand { background: var(--brand, currentColor); width: 26px; height: 26px; }
.si--lg { width: 44px; height: 44px; }
.si--text { -webkit-mask: none; mask: none; background: none; width: auto; font: 800 .62rem/18px var(--mono); letter-spacing: .02em; }

/* ---------- Hero ---------- */
.hero { display: grid; grid-template-columns: 1fr; gap: 2.5rem; padding-top: 3.5rem; padding-bottom: 2.5rem; align-items: center; }
@media (min-width: 900px) { .hero { grid-template-columns: 1.35fr 1fr; padding-top: 5rem; } }
.eyebrow { display: inline-flex; align-items: center; gap: .5rem; font-size: .8rem; color: var(--text-2); background: var(--bg-elev); border: 1px solid var(--border); padding: .35rem .7rem; border-radius: 999px; margin: 0 0 1.25rem; }
.dot { width: 8px; height: 8px; border-radius: 50%; background: #22c55e; box-shadow: 0 0 0 3px rgba(34, 197, 94, .2); }
.hero h1 { font-size: clamp(2.4rem, 7vw, 4rem); font-weight: 800; letter-spacing: -.03em; }
.hero__role { font-size: clamp(1.05rem, 2.6vw, 1.3rem); color: var(--text-2); margin: .6rem 0 1.1rem; font-weight: 500; }
.hero__lede { font-size: 1.07rem; color: var(--text-2); max-width: 62ch; margin: 0; }
.hero__cta { display: flex; flex-wrap: wrap; gap: .75rem; margin: 1.75rem 0 1.5rem; }
.socials { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: .5rem; }
.socials a { display: inline-flex; align-items: center; gap: .45rem; padding: .45rem .7rem; border-radius: 9px; border: 1px solid var(--border); background: var(--bg-elev); color: var(--text-2); font-size: .85rem; font-weight: 500; }
.socials a:hover { color: var(--text); border-color: var(--text-3); text-decoration: none; }

.hero__aside { display: grid; gap: 1.25rem; justify-items: center; }
.avatar { width: min(240px, 60vw); aspect-ratio: 1; border-radius: 28px; padding: 6px; background: linear-gradient(135deg, var(--accent), transparent 60%), var(--border); }
.avatar img { width: 100%; height: 100%; object-fit: cover; border-radius: 22px; }
.terminal { width: 100%; max-width: 380px; border-radius: 12px; border: 1px solid var(--border); background: var(--bg-elev); box-shadow: var(--shadow); overflow: hidden; }
.terminal__bar { display: flex; align-items: center; gap: 6px; padding: .55rem .8rem; border-bottom: 1px solid var(--border); background: var(--bg-sunk); }
.terminal__bar i { width: 10px; height: 10px; border-radius: 50%; background: var(--border); }
.terminal__bar i:nth-child(1) { background: #ff5f57; } .terminal__bar i:nth-child(2) { background: #febc2e; } .terminal__bar i:nth-child(3) { background: #28c840; }
.terminal__bar span { margin-left: auto; font-size: .72rem; color: var(--text-3); }
.terminal pre { margin: 0; padding: .9rem 1rem; font-size: .78rem; line-height: 1.6; color: var(--text-2); overflow-x: auto; }
.terminal .c { color: var(--accent); } .terminal .k { color: var(--text); font-weight: 600; } .terminal .s { color: #16a34a; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .terminal .s { color: #4ade80; } }
:root[data-theme="dark"] .terminal .s { color: #4ade80; }

/* ---------- Stats ---------- */
.stats { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(2, 1fr); gap: 1px; background: var(--border); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
@media (min-width: 720px) { .stats { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 1000px) { .stats { grid-template-columns: repeat(6, 1fr); } }
.stats li { background: var(--bg-elev); padding: 1.1rem 1rem; }
.stats strong { display: block; font-size: 1.9rem; font-weight: 800; letter-spacing: -.02em; color: var(--accent); line-height: 1.1; }
.stats span { font-size: .8rem; color: var(--text-3); line-height: 1.4; display: block; margin-top: .3rem; }

/* ---------- Sections ---------- */
.section { padding-top: 4.5rem; }
.section__title { font-size: clamp(1.5rem, 3.5vw, 2rem); font-weight: 750; margin-bottom: 1.5rem; display: flex; align-items: baseline; gap: .6rem; }
.section__title .mono { color: var(--accent); font-size: .95rem; font-weight: 600; }
.section__intro { color: var(--text-2); margin: -.75rem 0 1.5rem; max-width: 70ch; }
.group-title { font-size: 1.05rem; font-weight: 650; color: var(--text-2); margin: 2rem 0 1rem; }
.group-title:first-of-type { margin-top: 0; }

.card { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.35rem 1.4rem; box-shadow: var(--shadow); min-width: 0; }
.card h3 { font-size: 1.1rem; font-weight: 650; }
.card > p { color: var(--text-2); }

.grid { display: grid; gap: 1rem; grid-template-columns: 1fr; }
@media (min-width: 720px) { .grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 720px) { .grid--2 { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 960px) { .grid--3 { grid-template-columns: repeat(3, 1fr); } }

.bullets { margin: .75rem 0 0; padding-left: 1.15rem; color: var(--text-2); }
.bullets li { margin: .35rem 0; }
.bullets li::marker { color: var(--accent); }

/* About */
.about { display: grid; gap: 1.5rem; }
@media (min-width: 900px) { .about { grid-template-columns: 1.6fr 1fr; align-items: start; } }
.prose p { color: var(--text-2); margin: 0 0 1rem; max-width: 70ch; }
.facts h3 { margin-bottom: .75rem; }
.facts dl { margin: 0; display: grid; grid-template-columns: auto 1fr; gap: .55rem 1rem; font-size: .92rem; }
.facts dt { color: var(--text-3); font-weight: 500; }
.facts dd { margin: 0; color: var(--text); }

/* Experience */
.job__head { display: flex; gap: 1rem; align-items: center; }
.job__logo { width: 48px; height: 48px; border-radius: 12px; border: 1px solid var(--border); background: #fff; }
.job + .job { margin-top: 2rem; }
.job__head h3 { font-size: 1.2rem; }
.job__blurb { margin: 1rem 0 0; color: var(--text-2); font-style: italic; }
.subprojects { display: grid; gap: 1rem; margin-top: 1.5rem; }
@media (min-width: 960px) { .subprojects { grid-template-columns: repeat(3, 1fr); } }
.sub { background: var(--bg-sunk); border: 1px solid var(--border); border-radius: 12px; padding: 1.1rem 1.15rem; min-width: 0; }
.sub h4 { font-size: 1rem; font-weight: 650; }
.sub > p { color: var(--text-2); font-size: .92rem; margin: .5rem 0 0; }
.sub .bullets { font-size: .92rem; }

/* Open source */
.oss { display: grid; gap: 1rem; }
@media (min-width: 960px) { .oss { grid-template-columns: 1.25fr 1fr; align-items: start; } }
.oss__col { display: grid; gap: 1rem; }
.oss__card header { display: flex; align-items: center; gap: .75rem; margin-bottom: .5rem; }
.oss__card h3 small { display: block; font-size: .8rem; font-weight: 500; color: var(--text-3); margin-top: .15rem; }
.oss__card h4 { font-size: .9rem; font-weight: 650; margin: 1.1rem 0 .4rem; }
.mr { width: 100%; border-collapse: collapse; font-size: .88rem; }
.mr td { padding: .5rem 0; border-top: 1px solid var(--border); vertical-align: top; color: var(--text-2); }
.mr td:first-child { width: 5.2rem; padding-right: .75rem; font: 600 .82rem var(--mono); white-space: nowrap; }

/* Projects */
.project h4 { font-size: 1.05rem; font-weight: 650; display: flex; flex-wrap: wrap; align-items: baseline; gap: .5rem; }
.project h4 a:first-child { color: var(--text); }
.project h4 a:first-child:hover { color: var(--accent); }
.project p { color: var(--text-2); font-size: .94rem; margin: .6rem 0 0; }
.ext { font-size: .8rem; font-weight: 500; }
.star { font: 600 .78rem var(--mono); color: var(--accent); }

/* Repos */
.repo-controls { display: flex; flex-wrap: wrap; gap: .6rem; align-items: center; margin-bottom: .75rem; }
.search { flex: 1 1 240px; display: flex; align-items: center; gap: .5rem; padding: 0 .8rem; border: 1px solid var(--border); border-radius: 10px; background: var(--bg-elev); color: var(--text-3); }
.search input { flex: 1; min-width: 0; border: 0; background: transparent; color: var(--text); font: inherit; font-size: .95rem; padding: .65rem 0; outline: none; }
.repo-controls select { font: inherit; font-size: .9rem; padding: .6rem .7rem; border: 1px solid var(--border); border-radius: 10px; background: var(--bg-elev); color: var(--text); }
.check { display: inline-flex; align-items: center; gap: .4rem; font-size: .9rem; color: var(--text-2); cursor: pointer; }
.check input { accent-color: var(--accent); width: 16px; height: 16px; }
.repo-count { font-size: .8rem; color: var(--text-3); margin: 0 0 1rem; }
@media (min-width: 1000px) { .grid--repos { grid-template-columns: repeat(3, 1fr); } }
.repo { display: flex; flex-direction: column; padding: 1.1rem 1.2rem; transition: border-color .15s ease, transform .15s ease; }
.repo:hover { border-color: var(--text-3); transform: translateY(-2px); }
.repo__name { font: 600 .95rem var(--mono); color: var(--text); word-break: break-word; }
.repo__name:hover { color: var(--accent); }
.repo__fork { font: 500 .7rem var(--mono); color: var(--text-3); border: 1px solid var(--border); padding: .1rem .35rem; border-radius: 5px; margin-left: .35rem; vertical-align: middle; }
.repo__desc { color: var(--text-2); font-size: .88rem; margin: .5rem 0 .9rem; flex: 1; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.repo__meta { display: flex; flex-wrap: wrap; gap: .9rem; font: 500 .78rem var(--mono); color: var(--text-3); align-items: center; }
.repo__meta a { color: var(--text-3); }
.repo__meta a:hover { color: var(--accent); }
.lang-dot { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: .35rem; vertical-align: -1px; background: var(--c, var(--text-3)); }
.gh-graph { margin-top: 1.5rem; overflow-x: auto; }
.gh-graph img { min-width: 640px; width: 100%; }

/* Competitive programming */
.cf { list-style: none; padding: 0; margin: .75rem 0 0; display: grid; gap: .5rem; }
.cf li { display: grid; grid-template-columns: 1fr auto; grid-template-areas: "h r" "k r"; align-items: center; padding: .8rem 1rem; border-radius: 10px; background: var(--bg-sunk); border: 1px solid var(--border); }
.cf__handle { grid-area: h; font: 700 1rem var(--mono); }
.cf__rank { grid-area: k; font-size: .82rem; color: var(--text-3); text-transform: capitalize; }
.cf__rating { grid-area: r; font-size: 1.4rem; font-weight: 700; color: var(--text); text-align: right; line-height: 1.1; }
.cf__rating small { display: block; font-size: .7rem; font-weight: 500; color: var(--text-3); }
/* Codeforces rank colors */
.cf li[data-rank="newbie"] .cf__handle { color: #808080; }
.cf li[data-rank="pupil"] .cf__handle { color: #008000; }
.cf li[data-rank="specialist"] .cf__handle { color: #03a89e; }
.cf li[data-rank="expert"] .cf__handle { color: #3b5bdb; }
.cf li[data-rank="candidate master"] .cf__handle { color: #aa00aa; }
.cf li[data-rank="master"] .cf__handle, .cf li[data-rank="international master"] .cf__handle { color: #ff8c00; }
.cf li[data-rank*="grandmaster"] .cf__handle { color: #e03131; }
.card p:not(.meta) { color: var(--text-2); }

/* Timeline */
.timeline { list-style: none; padding: 0 0 0 1.25rem; margin: 0; display: grid; gap: 1rem; border-left: 2px solid var(--border); }
.timeline > li { position: relative; }
.timeline > li::before { content: ""; position: absolute; left: calc(-1.25rem - 7px); top: 1.6rem; width: 12px; height: 12px; border-radius: 50%; background: var(--bg); border: 2px solid var(--accent); }
.timeline h3 { font-size: 1.05rem; }

/* Education */
.cert { display: flex; gap: 1rem; align-items: flex-start; }
.cert p { margin: .25rem 0 0; }

/* Writing */
.posts { list-style: none; padding: 0; margin: 0; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-elev); overflow: hidden; }
.posts li { display: flex; flex-wrap: wrap; justify-content: space-between; gap: .25rem 1rem; padding: .95rem 1.2rem; border-top: 1px solid var(--border); }
.posts li:first-child { border-top: 0; }
.posts a { font-weight: 600; color: var(--text); }
.posts a:hover { color: var(--accent); }
.posts .meta { margin: 0; font-size: .78rem; }

/* Contact / footer */
.contact { text-align: center; padding-bottom: 2rem; }
.contact h2 { font-size: clamp(1.5rem, 4vw, 2.2rem); font-weight: 800; letter-spacing: -.02em; }
.contact p { color: var(--text-2); margin: .75rem 0 1.5rem; }
.footer { display: flex; flex-wrap: wrap; justify-content: space-between; gap: .5rem; padding-top: 2rem; padding-bottom: 2rem; margin-top: 3rem; border-top: 1px solid var(--border); color: var(--text-3); font-size: .85rem; }
.footer p { margin: 0; }

/* Reveal-on-scroll (only when JS enables it) */
.js .reveal { opacity: 0; transform: translateY(12px); transition: opacity .5s ease, transform .5s ease; }
.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .btn, .repo { transition: none; }
}

/* ---------- Print: a clean résumé ---------- */
@media print {
  :root { --bg: #fff; --bg-elev: #fff; --bg-sunk: #fff; --text: #000; --text-2: #222; --text-3: #555; --border: #ccc; --accent: #000; --shadow: none; }
  .nav, .hero__aside, .hero__cta, #repos, .contact, .footer, .skip { display: none !important; }
  body { font-size: 11pt; }
  .section { padding-top: 1.25rem; }
  .card, .sub { break-inside: avoid; box-shadow: none; }
  .js .reveal { opacity: 1; transform: none; }
  a { color: #000; }
}

/* Third-party contribution chart is light-only; flip lightness in dark mode while keeping hue */
:root[data-theme="dark"] .gh-graph img { filter: invert(1) hue-rotate(180deg) brightness(.95); }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .gh-graph img { filter: invert(1) hue-rotate(180deg) brightness(.95); }
}