/* ============================================================
   Zahirul Islam — portfolio stylesheet
   ============================================================ */
:root {
  --bg: #f7f5f0;
  --bg-elev: #ffffff;
  --bg-soft: #efece4;
  --ink: #15212d;
  --ink-2: #41505f;
  --ink-3: #6b7786;
  --line: #e2ddd2;
  --navy: #0f2a44;
  --navy-2: #163b5e;
  --accent: #c58a2a;
  --accent-soft: #f4e5c8;
  --teal: #1f6f6b;
  --teal-soft: #d9ecea;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(15, 33, 45, .06), 0 8px 24px -12px rgba(15, 33, 45, .18);
  --max: 1120px;
  --serif: "Fraunces", Georgia, "Times New Roman", serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
:root:not([data-theme="light"]) {
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e151d;
    --bg-elev: #141e29;
    --bg-soft: #1a2633;
    --ink: #e8eaee;
    --ink-2: #b7c0cb;
    --ink-3: #8794a3;
    --line: #243242;
    --navy: #0b1a2b;
    --navy-2: #122a44;
    --accent: #e3ad52;
    --accent-soft: #3a2d15;
    --teal: #5fbcb6;
    --teal-soft: #15302f;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 10px 30px -14px rgba(0,0,0,.7);
  }
}
:root[data-theme="dark"] {
  --bg: #0e151d;
  --bg-elev: #141e29;
  --bg-soft: #1a2633;
  --ink: #e8eaee;
  --ink-2: #b7c0cb;
  --ink-3: #8794a3;
  --line: #243242;
  --navy: #0b1a2b;
  --navy-2: #122a44;
  --accent: #e3ad52;
  --accent-soft: #3a2d15;
  --teal: #5fbcb6;
  --teal-soft: #15302f;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 10px 30px -14px rgba(0,0,0,.7);
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--teal); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
h1, h2, h3, h4 { font-family: var(--serif); font-weight: 600; line-height: 1.15; margin: 0 0 .5em; letter-spacing: -.01em; color: var(--ink); }
h1 { font-size: clamp(2.1rem, 4.5vw, 3.4rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); }
h3 { font-size: 1.2rem; }
p { margin: 0 0 1em; }
.muted { color: var(--ink-3); }
.lede { font-size: 1.15rem; color: var(--ink-2); max-width: 62ch; }
.wrap { width: min(var(--max), 100% - 32px); margin-inline: auto; }
.section { padding: clamp(48px, 7vw, 88px) 0; }
.section.tight { padding-block: clamp(32px, 5vw, 56px); }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 24px; margin-bottom: 28px; flex-wrap: wrap; }
.section-head p { margin: 0; max-width: 60ch; color: var(--ink-2); }
.eyebrow { font-family: var(--sans); font-size: .78rem; font-weight: 600; letter-spacing: .14em; text-transform: uppercase; color: var(--accent); margin-bottom: 10px; display: block; }
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 960px) { .grid-3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 620px) { .grid-3 { grid-template-columns: 1fr; } }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }

/* --- header --- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 66px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--serif); font-weight: 600; font-size: 1.15rem; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand-mark { width: 34px; height: 34px; border-radius: 9px; background: var(--navy); color: #f0b450; display: grid; place-items: center; font-size: .85rem; font-weight: 700; letter-spacing: .02em; }
.nav-links { display: flex; gap: 4px; list-style: none; margin: 0; padding: 0; }
.nav-links a { display: block; padding: 8px 12px; border-radius: 8px; color: var(--ink-2); font-size: .95rem; font-weight: 500; }
.nav-links a:hover { background: var(--bg-soft); text-decoration: none; color: var(--ink); }
.nav-links a[aria-current="page"] { color: var(--ink); background: var(--bg-soft); }
.nav-actions { display: flex; align-items: center; gap: 8px; }
.icon-btn { width: 38px; height: 38px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg-elev); color: var(--ink-2); display: grid; place-items: center; cursor: pointer; }
.icon-btn:hover { color: var(--ink); border-color: var(--ink-3); }
.icon-btn svg { width: 18px; height: 18px; }
.menu-btn { display: none; }
@media (max-width: 820px) {
  .nav-links { position: absolute; top: 66px; left: 0; right: 0; flex-direction: column; background: var(--bg-elev); border-bottom: 1px solid var(--line); padding: 10px 16px 16px; display: none; box-shadow: var(--shadow); }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 10px; font-size: 1.05rem; }
  .menu-btn { display: grid; }
}

/* --- buttons --- */
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 20px; border-radius: 10px; font-weight: 600; font-size: .95rem; border: 1px solid transparent; cursor: pointer; transition: transform .15s ease, background .15s ease; }
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--navy); color: #fff; }
.btn-primary:hover { background: var(--navy-2); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--ink-3); background: var(--bg-elev); }
.btn svg { width: 16px; height: 16px; }

/* --- hero --- */
.hero { padding: clamp(40px, 7vw, 96px) 0 clamp(36px, 6vw, 72px); }
.hero-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: clamp(28px, 5vw, 64px); align-items: center; }
.hero h1 .accent { color: var(--accent); font-style: italic; font-weight: 500; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 8px; margin: 18px 0 26px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }
.portrait { position: relative; max-width: 380px; margin-inline: auto; }
.portrait img { border-radius: 22px; aspect-ratio: 3 / 4; object-fit: cover; box-shadow: var(--shadow); }
.portrait::before { content: ""; position: absolute; inset: 18px -18px -18px 18px; border-radius: 22px; background: linear-gradient(135deg, var(--accent-soft), var(--teal-soft)); z-index: -1; }
.portrait-badge { position: absolute; left: -12px; bottom: 28px; background: var(--bg-elev); border: 1px solid var(--line); border-radius: 12px; padding: 10px 14px; box-shadow: var(--shadow); font-size: .85rem; }
.portrait-badge strong { display: block; font-size: 1.1rem; font-family: var(--serif); }
@media (max-width: 880px) {
  .hero-grid { grid-template-columns: 1fr; }
  .portrait { max-width: 320px; order: -1; }
  .portrait::before { inset: 12px -12px -12px 12px; }
}

/* --- chips / tags --- */
.chip { display: inline-flex; align-items: center; gap: 6px; padding: 5px 11px; border-radius: 999px; font-size: .8rem; font-weight: 500; background: var(--bg-soft); color: var(--ink-2); border: 1px solid var(--line); white-space: nowrap; }
.chip.accent { background: var(--accent-soft); color: var(--ink); border-color: transparent; }
.chip.teal { background: var(--teal-soft); color: var(--ink); border-color: transparent; }

/* --- stats --- */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 14px; }
.stat { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 20px 16px; }
.stat b { display: block; font-family: var(--serif); font-size: 2.1rem; font-weight: 600; line-height: 1; color: var(--navy); }
:root[data-theme="dark"] .stat b { color: var(--accent); }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .stat b { color: var(--accent); } }
.stat span { color: var(--ink-3); font-size: .9rem; }

/* --- cards --- */
.card { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; box-shadow: 0 1px 0 rgba(0,0,0,.02); display: flex; flex-direction: column; gap: 10px; }
.card h3 { margin: 0; }
.card .meta { font-size: .85rem; color: var(--ink-3); display: flex; flex-wrap: wrap; gap: 6px 14px; }
.card p { margin: 0; color: var(--ink-2); }
.card-icon { width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center; background: var(--teal-soft); color: var(--teal); margin-bottom: 4px; }
.card-icon svg { width: 22px; height: 22px; }
.card.feature { border-top: 3px solid var(--accent); }
.card .foot { margin-top: auto; padding-top: 8px; display: flex; flex-wrap: wrap; gap: 6px; }

/* --- band --- */
.band { background: var(--navy); color: #e9eef5; }
.band h2, .band h3 { color: #fff; }
.band .muted { color: #9fb0c4; }
.band .chip { background: rgba(255,255,255,.08); border-color: rgba(255,255,255,.14); color: #e9eef5; }
.band a { color: #ffd38a; }
.logo-wall { display: flex; flex-wrap: wrap; gap: 10px 26px; margin-top: 18px; }
.logo-wall span { font-family: var(--serif); font-size: 1.05rem; color: #c9d4e2; opacity: .9; }

/* --- timeline --- */
.timeline { position: relative; padding-left: 28px; }
.timeline::before { content: ""; position: absolute; left: 8px; top: 6px; bottom: 6px; width: 2px; background: var(--line); }
.tl-item { position: relative; padding: 0 0 36px; }
.tl-item::before { content: ""; position: absolute; left: -26px; top: 6px; width: 14px; height: 14px; border-radius: 50%; background: var(--accent); border: 3px solid var(--bg); box-shadow: 0 0 0 2px var(--line); }
.tl-item .when { font-size: .85rem; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--accent); }
.tl-item h3 { margin: 4px 0 2px; }
.tl-item .org { color: var(--ink-2); font-weight: 500; margin-bottom: 10px; }
.tl-item ul { margin: 8px 0 0; padding-left: 18px; color: var(--ink-2); }
.tl-item li { margin-bottom: 4px; }

/* --- skills --- */
.skill-group { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 22px; }
.skill-group h3 { font-size: 1.05rem; margin-bottom: 10px; }
.skill-group .chips { display: flex; flex-wrap: wrap; gap: 6px; }

/* --- list rows (education, training, publications) --- */
.rows { display: grid; gap: 12px; }
.row { display: grid; grid-template-columns: 120px 1fr; gap: 18px; padding: 18px 20px; background: var(--bg-elev); border: 1px solid var(--line); border-radius: 12px; }
.row .when { font-weight: 600; color: var(--accent); font-size: .9rem; }
.row h3, .row h4 { margin: 0 0 4px; font-size: 1.05rem; }
.row p { margin: 0; color: var(--ink-2); }
.row small { color: var(--ink-3); }
@media (max-width: 600px) { .row { grid-template-columns: 1fr; gap: 4px; } }

/* --- projects explorer --- */
.toolbar { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 10px; margin-bottom: 18px; }
.toolbar input, .toolbar select { width: 100%; padding: 11px 14px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg-elev); color: var(--ink); font: inherit; font-size: .95rem; }
.toolbar input:focus, .toolbar select:focus { outline: 2px solid var(--teal); outline-offset: 1px; }
@media (max-width: 700px) { .toolbar { grid-template-columns: 1fr; } }
.count { font-size: .9rem; color: var(--ink-3); margin-bottom: 14px; }
.plist { display: grid; gap: 10px; }
.pitem { display: grid; grid-template-columns: 110px 1fr auto; gap: 16px; align-items: start; padding: 16px 18px; background: var(--bg-elev); border: 1px solid var(--line); border-radius: 12px; }
.pitem .year { font-family: var(--serif); font-size: 1.1rem; font-weight: 600; color: var(--navy); }
:root[data-theme="dark"] .pitem .year { color: var(--accent); }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .pitem .year { color: var(--accent); } }
.pitem .year small { display: block; font-family: var(--sans); font-size: .75rem; font-weight: 500; color: var(--ink-3); }
.pitem h4 { margin: 0 0 4px; font-size: 1rem; font-family: var(--sans); font-weight: 600; }
.pitem .meta { font-size: .85rem; color: var(--ink-3); display: flex; flex-wrap: wrap; gap: 4px 14px; }
.pitem .meta b { color: var(--ink-2); font-weight: 500; }
@media (max-width: 700px) { .pitem { grid-template-columns: 1fr; gap: 6px; } .pitem .chip { justify-self: start; } }
.empty { padding: 32px; text-align: center; color: var(--ink-3); border: 1px dashed var(--line); border-radius: 12px; }

/* --- publications --- */
.pub { padding: 20px 22px; background: var(--bg-elev); border: 1px solid var(--line); border-radius: 12px; }
.pub .type { font-size: .75rem; font-weight: 600; letter-spacing: .1em; text-transform: uppercase; color: var(--teal); }
.pub h3 { font-size: 1.1rem; margin: 6px 0 6px; }
.pub .authors { color: var(--ink-2); font-size: .95rem; }
.pub .venue { color: var(--ink-3); font-size: .9rem; margin-top: 4px; }
.pub .links { margin-top: 10px; display: flex; gap: 14px; flex-wrap: wrap; font-size: .9rem; }

/* --- contact --- */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
@media (max-width: 800px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.contact-list li { display: flex; align-items: center; gap: 14px; padding: 14px 16px; background: var(--bg-elev); border: 1px solid var(--line); border-radius: 12px; }
.contact-list .ic { width: 40px; height: 40px; border-radius: 10px; background: var(--bg-soft); display: grid; place-items: center; color: var(--ink-2); flex: none; }
.contact-list .ic svg { width: 18px; height: 18px; }
.contact-list small { display: block; color: var(--ink-3); font-size: .78rem; text-transform: uppercase; letter-spacing: .08em; }
.form { display: grid; gap: 12px; }
.form label { font-size: .85rem; font-weight: 600; color: var(--ink-2); display: grid; gap: 6px; }
.form input, .form textarea { padding: 12px 14px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg-elev); color: var(--ink); font: inherit; }
.form textarea { min-height: 140px; resize: vertical; }
.form input:focus, .form textarea:focus { outline: 2px solid var(--teal); outline-offset: 1px; }

/* --- footer --- */
.site-footer { border-top: 1px solid var(--line); padding: 32px 0 40px; color: var(--ink-3); font-size: .9rem; }
.social { display: flex; gap: 8px; }
.social a { width: 36px; height: 36px; border-radius: 9px; display: grid; place-items: center; color: var(--ink-2); border: 1px solid var(--line); background: var(--bg-elev); }
.social a:hover { color: var(--ink); border-color: var(--ink-3); text-decoration: none; }
.social svg { width: 17px; height: 17px; }

/* --- page hero (inner pages) --- */
.page-hero { padding: clamp(40px, 6vw, 72px) 0 clamp(20px, 3vw, 32px); }
.page-hero h1 { margin-bottom: 10px; }

/* --- utilities --- */
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.mt-0 { margin-top: 0; } .mb-0 { margin-bottom: 0; }
.center { text-align: center; }
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .55s ease, transform .55s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } html { scroll-behavior: auto; } }
@media print { .site-header, .site-footer, .hero-actions, .toolbar { display: none !important; } body { background: #fff; color: #000; } }

/* --- footer signature --- */
.sig { display: grid; grid-template-columns: 1.25fr 1fr 1fr; gap: 0; background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.sig-col { padding: 26px 28px; display: flex; flex-direction: column; align-items: flex-start; gap: 4px; min-width: 0; }
.sig-col + .sig-col { border-left: 1px solid var(--line); }
.sig-name { font-family: var(--serif); font-size: 1.6rem; font-weight: 600; line-height: 1.1; color: var(--ink); }
.sig-title { color: var(--ink-2); font-weight: 500; }
.sig-tag { margin: 8px 0 0; color: var(--ink-3); font-size: .85rem; line-height: 1.5; max-width: 38ch; }
.sig-meta { display: flex; flex-wrap: wrap; gap: 4px 8px; margin-top: 10px; color: var(--ink-3); font-size: .9rem; }
.sig-links { display: flex; flex-wrap: wrap; gap: 6px 18px; margin-top: 12px; font-size: .9rem; font-weight: 500; }
.sig-logo { display: inline-flex; align-items: center; gap: 10px; height: 40px; margin-bottom: 10px; text-decoration: none; color: inherit; }
.sig-logo img { height: 40px; width: auto; display: block; }
.sig-org-name { font-family: var(--serif); font-size: 1.15rem; font-weight: 600; color: var(--ink); line-height: 1.1; }
.sig-logo:hover .sig-org-name { color: var(--teal); }
.sig-logo .logo-dark { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .sig-logo .logo-light { display: none; }
  :root:not([data-theme="light"]) .sig-logo .logo-dark { display: block; }
}
:root[data-theme="dark"] .sig-logo .logo-light { display: none; }
:root[data-theme="dark"] .sig-logo .logo-dark { display: block; }
.sig-org a { color: var(--ink-2); font-size: .9rem; overflow-wrap: anywhere; }
.sig-org a:hover { color: var(--teal); }
.foot-bar { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; margin-top: 22px; }
@media (max-width: 960px) {
  .sig { grid-template-columns: 1fr 1fr; }
  .sig-id { grid-column: 1 / -1; border-bottom: 1px solid var(--line); }
  .sig-col + .sig-col { border-left: 0; }
  .sig-org + .sig-org { border-left: 1px solid var(--line); }
}
@media (max-width: 560px) {
  .sig { grid-template-columns: 1fr; }
  .sig-org + .sig-org { border-left: 0; border-top: 1px solid var(--line); }
  .sig-col { padding: 22px 20px; }
  .foot-bar { flex-direction: column; align-items: flex-start; }
}
.psum { margin: 0 0 6px; color: var(--ink-2); font-size: .9rem; }