/* ============================================================
   Rashidul Hasan Hridoy — Academic Portfolio
   Design: clinical paper surface, slate-navy ink, signal-teal accent.
   Type:   Space Grotesk (display) / Inter (body) / JetBrains Mono (data)
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@300;400;500;600;700&family=Inter:wght@300;400;500;600&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ---------- Design tokens ---------- */
:root {
  /* surfaces — cool clinical paper, not warm cream */
  --surface-0: #f7f8fa;
  --surface-1: #eef1f4;
  --surface-2: #e4e8ec;

  /* ink — deep slate navy, never pure black */
  --text-primary: #161c26;
  --text-secondary: #4b5567;
  --text-muted: #808999;

  /* accent — signal teal, the page's one accent color */
  --text-accent: #0d7a73;
  --bg-accent: #e3f3f1;
  --border-accent: #b9ddd8;
  --fill-accent: #14a89e;

  /* flag colors, used only in the hero pulse sweep */
  --bd-red: #f42a41;
  --bd-green: #006a4e;

  /* status */
  --text-success: #1c7a4d;
  --bg-success: #e1f3e8;
  --text-warning: #9a6a00;
  --bg-warning: #fbeed2;

  /* structure */
  --border: #dde1e6;
  --border-strong: #ccd2da;
  --border-stronger: #b7bfc9;
  --radius: 10px;

  /* shadow, used sparingly */
  --shadow-soft: 0 1px 2px rgba(22, 28, 38, 0.04), 0 8px 24px -12px rgba(22, 28, 38, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --surface-0: #0f1217;
    --surface-1: #161a21;
    --surface-2: #1e232c;

    --text-primary: #eef1f5;
    --text-secondary: #aab2c0;
    --text-muted: #707888;

    --text-accent: #4fd1c5;
    --bg-accent: #13302e;
    --border-accent: #1f4744;
    --fill-accent: #4fd1c5;

    --text-success: #6fcf97;
    --bg-success: #14301f;
    --text-warning: #e0b35c;
    --bg-warning: #332608;

    --border: #262b34;
    --border-strong: #323844;
    --border-stronger: #424a58;

    --shadow-soft: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px -12px rgba(0, 0, 0, 0.5);
  }
}

/* ---------- Reset & base ---------- */
* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--surface-0);
  color: var(--text-primary);
}

::selection { background: var(--border-accent); color: var(--text-primary); }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}

a { font-family: inherit; }

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

/* ---------- Page shell ---------- */
.site {
  font-family: 'Inter', sans-serif;
  color: var(--text-primary);
  background: var(--surface-0);
  max-width: 900px;
  margin: 0 auto;
  min-height: 100vh;
  box-shadow: var(--shadow-soft);
}

/* ---------- Nav ---------- */
.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  row-gap: 0.65rem;
  padding: 1.25rem 2rem;
  border-bottom: 0.5px solid var(--border);
  position: sticky;
  top: 0;
  background: color-mix(in srgb, var(--surface-0) 92%, transparent);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  z-index: 10;
}
.nav-logo {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.nav-flag {
  font-size: 14px;
  letter-spacing: normal;
  text-transform: none;
  line-height: 1;
}
.nav-links { display: flex; gap: 1.5rem; flex-wrap: wrap; }
.nav-links a {
  font-size: 13px;
  color: var(--text-secondary);
  text-decoration: none;
  letter-spacing: 0.02em;
  position: relative;
  padding-bottom: 2px;
  transition: color 0.15s;
}
.nav-links a::after {
  content: '';
  position: absolute;
  left: 0; right: 100%;
  bottom: -1px;
  height: 1.5px;
  background: var(--fill-accent);
  transition: right 0.2s ease;
}
.nav-links a:hover { color: var(--text-primary); }
.nav-links a:hover::after { right: 0; }

/* ---------- Hero ---------- */
.hero { padding: 5rem 2rem 4rem; border-bottom: 0.5px solid var(--border); position: relative; }
.hero-eyebrow {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-accent);
  margin-bottom: 1.25rem;
  font-weight: 500;
}
.hero-name {
  font-family: 'Space Grotesk', sans-serif;
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

#name-text {
  background-image: linear-gradient(
    100deg,
    var(--text-primary) 0%,
    var(--text-primary) 30%,
    var(--bd-red) 45%,
    var(--bd-green) 55%,
    var(--text-primary) 70%,
    var(--text-primary) 100%
  );
  background-size: 220% 100%;
  background-position: 200% 0;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: flag-reflect 6s ease-in-out infinite;
  animation-delay: 1s;
}
@keyframes flag-reflect {
  0% { background-position: 200% 0; }
  45%, 65% { background-position: -100% 0; }
  100% { background-position: -100% 0; }
}
@media (prefers-reduced-motion: reduce) {
  #name-text { animation: none; background-position: -100% 0; }
}

.hero-pulse {
  height: 3px;
  width: 100%;
  max-width: 480px;
  margin: 1.25rem 0 1.75rem;
  position: relative;
  overflow: hidden;
  background: var(--border);
  border-radius: 2px;
}
.hero-pulse::after {
  content: '';
  position: absolute;
  top: 0; left: -60%;
  width: 60%; height: 100%;
  background: linear-gradient(90deg, transparent, var(--bd-red) 45%, var(--bd-green) 55%, transparent);
  animation: pulse-sweep 2s ease-in-out infinite;
}
@keyframes pulse-sweep {
  0% { left: -60%; }
  100% { left: 110%; }
}

.hero-role { font-size: 15px; color: var(--text-secondary); margin-bottom: 1.5rem; line-height: 1.6; }
.hero-role strong { color: var(--text-primary); font-weight: 500; }
.hero-bio { font-size: 15px; color: var(--text-secondary); line-height: 1.75; max-width: 600px; margin-bottom: 2rem; }
.hero-links { display: flex; flex-wrap: wrap; gap: 0.5rem; }

/* ---------- Pills ---------- */
.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 500;
  padding: 5px 12px;
  border-radius: 99px;
  border: 0.5px solid var(--border-strong);
  color: var(--text-secondary);
  text-decoration: none;
  transition: all 0.15s;
  background: var(--surface-1);
}
.pill:hover {
  color: var(--text-primary);
  border-color: var(--border-stronger);
  background: var(--surface-2);
  transform: translateY(-1px);
}
.pill i { font-size: 13px; line-height: 1; }
.pill-accent { background: var(--bg-accent); border-color: var(--border-accent); color: var(--text-accent); }
.pill-accent:hover { background: var(--bg-accent); color: var(--text-accent); }

/* ---------- Section scaffolding ---------- */
.section {
  padding: 3.5rem 2rem;
  border-bottom: 0.5px solid var(--border);
  scroll-margin-top: 4.5rem;
}
.section:last-of-type { border-bottom: none; }
.section-header { display: flex; align-items: baseline; gap: 1rem; margin-bottom: 2.5rem; }
.section-title {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
}
.section-rule { flex: 1; height: 0.5px; background: var(--border); }

/* ---------- Education ---------- */
.edu-block { max-width: 640px; }
.edu-degree { font-family: 'Space Grotesk', sans-serif; font-size: 16px; font-weight: 600; color: var(--text-primary); margin-bottom: 4px; }
.edu-meta { font-family: 'JetBrains Mono', monospace; font-size: 12.5px; color: var(--text-muted); margin-bottom: 1rem; }
.edu-cgpa {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 99px;
  background: var(--bg-success);
  color: var(--text-success);
  margin-left: 8px;
}
.edu-body { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }
.edu-body a { color: var(--text-accent); text-decoration: none; }
.edu-body a:hover { text-decoration: underline; }

.thesis-pubs {
  margin-top: 1rem;
  padding: 1rem 1.25rem;
  background: var(--surface-1);
  border: 0.5px solid var(--border);
  border-radius: 12px;
}
.thesis-pubs-label { font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-muted); font-weight: 600; margin-bottom: 0.75rem; }
.thesis-pub-item {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
  padding: 0.5rem 0;
  border-bottom: 0.5px solid var(--border);
  display: flex;
  gap: 0.75rem;
}
.thesis-pub-item:last-child { border-bottom: none; padding-bottom: 0; }
.thesis-pub-item strong { color: var(--text-primary); font-weight: 500; }
.thesis-pub-num { font-family: 'JetBrains Mono', monospace; font-size: 11px; font-weight: 700; color: var(--text-muted); min-width: 18px; padding-top: 1px; }

/* ---------- Publications ---------- */
.pub-group { margin-bottom: 2.5rem; }
.pub-group:last-child { margin-bottom: 0; }
.pub-group-label {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-weight: 600;
  color: var(--text-accent);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 0.5px solid var(--border-accent);
  display: flex;
  align-items: center;
  gap: 8px;
}
.pub-count {
  font-family: 'JetBrains Mono', monospace;
  background: var(--bg-accent);
  color: var(--text-accent);
  font-size: 11px;
  font-weight: 600;
  padding: 1px 7px;
  border-radius: 99px;
}
.pub-item { display: flex; gap: 1rem; padding: 1rem 0; border-bottom: 0.5px solid var(--border); align-items: flex-start; }
.pub-item:last-child { border-bottom: none; }
.pub-left { display: flex; flex-direction: column; align-items: center; gap: 6px; min-width: 32px; padding-top: 2px; }
.pub-num { font-family: 'JetBrains Mono', monospace; font-size: 11px; font-weight: 700; color: var(--text-muted); }
.pub-year-tag {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 4px;
  background: var(--surface-1);
  border: 0.5px solid var(--border);
  color: var(--text-muted);
}
.pub-body { font-size: 13.5px; color: var(--text-secondary); line-height: 1.65; flex: 1; }
.pub-body strong { color: var(--text-primary); font-weight: 500; }
.pub-venue { font-size: 12px; font-style: italic; color: var(--text-muted); margin-top: 3px; }
.pub-new-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 99px;
  background: var(--bg-success);
  color: var(--text-success);
  margin-left: 6px;
  vertical-align: middle;
}

/* ---------- Stats ---------- */
.stat-row { display: flex; gap: 12px; margin-bottom: 2rem; flex-wrap: wrap; }
.stat-card {
  background: var(--surface-1);
  border: 0.5px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem 1.1rem;
  flex: 1;
  min-width: 110px;
  transition: border-color 0.15s, transform 0.15s;
}
.stat-card:hover { border-color: var(--border-accent); transform: translateY(-1px); }
.stat-label { font-size: 12px; color: var(--text-muted); margin-bottom: 4px; }
.stat-val { font-family: 'JetBrains Mono', monospace; font-size: 22px; font-weight: 500; color: var(--text-primary); }
.scholar-note { font-size: 12px; color: var(--text-muted); margin-bottom: 2rem; display: flex; align-items: center; gap: 6px; flex-wrap: wrap; }

/* ---------- Skills ---------- */
.skills-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 12px; }
.skill-card {
  background: var(--surface-1);
  border: 0.5px solid var(--border);
  border-radius: 12px;
  padding: 1rem 1.25rem;
  transition: border-color 0.15s;
}
.skill-card:hover { border-color: var(--border-accent); }
.skill-card-label { font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-muted); font-weight: 600; margin-bottom: 0.6rem; }
.skill-tags { display: flex; flex-wrap: wrap; gap: 5px; }
.skill-tag {
  font-size: 12px;
  color: var(--text-secondary);
  background: var(--surface-2);
  border: 0.5px solid var(--border);
  border-radius: 4px;
  padding: 2px 8px;
}

/* ---------- Review activities ---------- */
.review-intro { font-size: 14px; color: var(--text-secondary); line-height: 1.7; margin-bottom: 1.5rem; max-width: 640px; }
.journal-grid {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-bottom: 1.5rem;
  border: 0.5px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.journal-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0.75rem 1rem;
  border-bottom: 0.5px solid var(--border);
  font-size: 13.5px;
  color: var(--text-secondary);
  transition: background 0.15s;
}
.journal-item:hover { background: var(--surface-1); }
.journal-item:last-child { border-bottom: none; }
.journal-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--fill-accent); flex-shrink: 0; }
.review-stat {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0.6rem 1rem;
  background: var(--bg-accent);
  border: 0.5px solid var(--border-accent);
  border-radius: var(--radius);
  font-size: 13px;
  color: var(--text-accent);
  font-weight: 500;
}

/* ---------- Awards ---------- */
.award-list { display: flex; flex-direction: column; gap: 12px; }
.award-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1rem 1.25rem;
  background: var(--surface-1);
  border: 0.5px solid var(--border);
  border-radius: 12px;
  transition: border-color 0.15s;
}
.award-item:hover { border-color: var(--border-strong); }
.award-icon { font-size: 20px; color: var(--text-warning); flex-shrink: 0; margin-top: 1px; }
.award-body { flex: 1; }
.award-title { font-size: 14px; font-weight: 500; color: var(--text-primary); margin-bottom: 3px; }
.award-meta { font-size: 13px; color: var(--text-secondary); }
.award-year {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  font-weight: 600;
  padding: 1px 7px;
  border-radius: 99px;
  background: var(--bg-warning);
  color: var(--text-warning);
  margin-left: 6px;
}

/* ---------- Contact ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.contact-item { display: flex; flex-direction: column; gap: 4px; }
.contact-label { font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-muted); font-weight: 600; }
.contact-value { font-size: 13px; color: var(--text-accent); text-decoration: none; word-break: break-word; }
.contact-value:hover { text-decoration: underline; }
.profile-links-row { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 1.5rem; }

/* ---------- Footer ---------- */
.footer { padding: 1.5rem 2rem; text-align: center; font-size: 12px; color: var(--text-muted); }

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
  .nav { padding: 1rem 1.25rem; }
  .nav-links { gap: 1rem; }
  .hero { padding: 3.5rem 1.25rem 2.75rem; }
  .section { padding: 2.5rem 1.25rem; }
  .contact-grid { grid-template-columns: 1fr; }
  .stat-row { gap: 8px; }
  .stat-card { min-width: 45%; }
}

@media (max-width: 600px) {
  .nav {
    flex-direction: column;
    align-items: flex-start;
    row-gap: 0.85rem;
  }
  .nav-links { gap: 0.85rem 1rem; }
}