/* ═══════════════════════════════════════════════════════
   Md. Tahmid Hasan Fuad — Portfolio
   Shared Stylesheet · "Colorful Academic" theme
   ═══════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,400..700;1,9..144,400..600&family=DM+Sans:ital,opsz,wght@0,9..40,300..700;1,9..40,300..700&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  /* ── Surfaces ── */
  --bg: #f7f5ef;
  --bg-tint: #f1eee5;
  --surface: #ffffff;
  --surface-hover: #fcfbf8;

  /* ── Ink ── */
  --ink: #1c1b2e;
  --ink-soft: #4a4860;
  --ink-dim: #807e96;

  /* ── Brand multi-accent palette ── */
  --violet: #6d4aff;
  --violet-soft: #efeaff;
  --blue: #2563eb;
  --blue-soft: #e4eeff;
  --teal: #0d9488;
  --teal-soft: #d9f3ef;
  --amber: #e0820c;
  --amber-soft: #fdeecf;
  --rose: #e11d48;
  --rose-soft: #ffe4ea;
  --green: #16a34a;
  --green-soft: #dcfce7;

  /* ── Primary (used for nav, links, focal accents) ── */
  --primary: var(--violet);
  --primary-soft: var(--violet-soft);

  --border: rgba(28,27,46,0.10);
  --border-strong: rgba(28,27,46,0.18);
  --shadow-sm: 0 1px 2px rgba(28,27,46,0.04), 0 2px 8px rgba(28,27,46,0.04);
  --shadow-md: 0 4px 16px rgba(28,27,46,0.08), 0 2px 6px rgba(28,27,46,0.05);
  --shadow-lg: 0 12px 36px rgba(109,74,255,0.14);

  --serif: 'Fraunces', Georgia, serif;
  --sans: 'DM Sans', system-ui, sans-serif;
  --mono: 'JetBrains Mono', monospace;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --transition: 0.28s var(--ease);
  --max-w: 1000px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--primary) transparent;
}

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: inherit; text-decoration: none; }

/* ── Soft colored mesh anchored top of page ── */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(640px circle at 8% -5%, rgba(109,74,255,0.10), transparent 45%),
    radial-gradient(560px circle at 95% 0%, rgba(37,99,235,0.08), transparent 42%),
    radial-gradient(520px circle at 60% 8%, rgba(13,148,136,0.06), transparent 40%);
  pointer-events: none;
  z-index: 0;
}

/* ─── NAVIGATION ──────────────────────────────────────── */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 0.85rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  backdrop-filter: blur(20px) saturate(1.6);
  -webkit-backdrop-filter: blur(20px) saturate(1.6);
  background: rgba(247,245,239,0.78);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}
nav.scrolled { padding: 0.6rem 2rem; background: rgba(247,245,239,0.94); box-shadow: var(--shadow-sm); }

.nav-logo {
  font-family: var(--serif);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: -0.02em;
}
.nav-logo span { color: var(--primary); }

.nav-links { display: flex; gap: 0.25rem; list-style: none; }

.nav-links a {
  color: var(--ink-soft);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  padding: 0.45rem 0.95rem;
  border-radius: 100px;
  transition: var(--transition);
}
.nav-links a:hover { color: var(--ink); background: var(--bg-tint); }
.nav-links a.active { color: var(--primary); background: var(--primary-soft); }

.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; background: none; border: none; padding: 4px; }
.hamburger span { width: 22px; height: 2px; background: var(--ink); transition: var(--transition); border-radius: 2px; }

/* ─── PAGE WRAPPER ────────────────────────────────────── */
.page { flex: 1; padding-top: 4.5rem; position: relative; z-index: 1; }
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 2rem; }

/* ─── PAGE HEADER ─────────────────────────────────────── */
.page-header { padding: 4rem 0 3rem; margin-bottom: 3rem; border-bottom: 1px solid var(--border); }

.page-header .breadcrumb {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--ink-dim);
  margin-bottom: 1rem;
  display: flex; align-items: center; gap: 0.5rem;
}
.page-header .breadcrumb a { color: var(--primary); font-weight: 500; }
.page-header .breadcrumb a:hover { text-decoration: underline; }

.page-header h1 {
  font-family: var(--serif);
  font-size: clamp(2.2rem, 4.5vw, 3.2rem);
  color: var(--ink);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.05;
}
.page-header p { font-size: 1.02rem; color: var(--ink-soft); margin-top: 0.75rem; max-width: 600px; }

/* ─── CARDS ───────────────────────────────────────────── */
.card {
  padding: 1.5rem;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}
.card:hover { border-color: var(--border-strong); box-shadow: var(--shadow-md); transform: translateY(-3px); }

/* ─── TAGS ────────────────────────────────────────────── */
.tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 0.22rem 0.65rem;
  background: var(--bg-tint);
  color: var(--ink-soft);
  border-radius: 100px;
}

/* ─── VENUE BADGES (colorful) ─────────────────────────── */
.badge {
  font-family: var(--mono);
  font-size: 0.72rem;
  padding: 0.28rem 0.7rem;
  border-radius: 100px;
  font-weight: 600;
  white-space: nowrap;
}
.badge-astar { background: var(--amber-soft); color: var(--amber); }
.badge-q1    { background: var(--green-soft); color: var(--green); }
.badge-conf  { background: var(--blue-soft);  color: var(--blue); }
.badge-pre   { background: var(--bg-tint);    color: var(--ink-dim); }

/* ─── LINK ARROW ──────────────────────────────────────── */
.arrow-link {
  display: inline-flex; align-items: center; gap: 0.4rem;
  font-size: 0.85rem; font-weight: 600; color: var(--primary);
  transition: var(--transition);
}
.arrow-link:hover { gap: 0.65rem; }
.arrow-link::after { content: '→'; transition: inherit; }

/* ─── FOOTER ──────────────────────────────────────────── */
footer { border-top: 1px solid var(--border); padding: 3rem 2rem; margin-top: 4rem; position: relative; z-index: 1; }
.footer-inner { max-width: var(--max-w); margin: 0 auto; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 1rem; }
.footer-copy { font-size: 0.8rem; color: var(--ink-dim); }
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a { font-size: 0.82rem; font-weight: 500; color: var(--ink-soft); transition: var(--transition); }
.footer-links a:hover { color: var(--primary); }

/* ─── SCROLL REVEAL ───────────────────────────────────── */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.55s ease, transform 0.55s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal.d1 { transition-delay: 0.07s; }
.reveal.d2 { transition-delay: 0.14s; }
.reveal.d3 { transition-delay: 0.21s; }
.reveal.d4 { transition-delay: 0.28s; }

/* ─── RESPONSIVE ──────────────────────────────────────── */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; flex-direction: column;
    position: absolute; top: 100%; left: 0; right: 0;
    background: rgba(247,245,239,0.98);
    backdrop-filter: blur(20px);
    padding: 1rem; gap: 0.25rem;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-md);
  }
  .nav-links.open a { padding: 0.65rem 1rem; }
  .hamburger { display: flex; }
  .container { padding: 0 1.25rem; }
  .page-header { padding: 3rem 0 2rem; margin-bottom: 2rem; }
  .footer-inner { flex-direction: column; text-align: center; }
}