/* Abhishek Shekhar — Academic Personal Site
   Palette adapted from mohammadmahoor.com (blue instead of red) */

:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f6f8fb;
  --color-surface: #ffffff;
  --color-border: #e5e9f0;
  --color-text: #1a2233;
  --color-text-muted: #5a6478;
  --color-text-soft: #7a8294;

  --color-accent: #1d4ed8;
  --color-accent-dark: #1e3a8a;
  --color-accent-soft: #e6edfb;
  --color-accent-tint: #f1f5fd;

  --color-gold: #b07a2b;

  --font-serif: "Source Serif Pro", "Source Serif 4", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", "Helvetica Neue", Arial, sans-serif;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 6px 24px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 18px 48px rgba(15, 23, 42, 0.12);

  --max-width: 1180px;
  --header-height: 76px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; display: block; }

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.15s ease;
}
a:hover { color: var(--color-accent-dark); }

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  color: var(--color-text);
  margin: 0 0 0.5em;
  line-height: 1.2;
  letter-spacing: -0.01em;
}
h1 { font-size: clamp(2rem, 1.4rem + 2.4vw, 3.4rem); font-weight: 600; }
h2 { font-size: clamp(1.6rem, 1.2rem + 1.2vw, 2.25rem); font-weight: 600; }
h3 { font-size: 1.35rem; font-weight: 600; }
h4 { font-size: 1.1rem; font-weight: 600; }
p { margin: 0 0 1em; color: var(--color-text); }

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.topbar {
  background: var(--color-accent-dark);
  color: #d6e0f5;
  font-size: 0.82rem;
}
.topbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 36px;
}
.topbar a { color: #d6e0f5; }
.topbar a:hover { color: #ffffff; }
.topbar .social a { margin-left: 0.85rem; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--color-border);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 1.2rem;
  color: var(--color-text);
}
.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--color-accent);
  color: #fff;
  display: grid;
  place-items: center;
  font-family: var(--font-serif);
  font-weight: 600;
}
.nav {
  display: flex;
  align-items: center;
  gap: 1.6rem;
}
.nav a {
  color: var(--color-text);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.4rem 0;
  position: relative;
}
.nav a.active,
.nav a:hover { color: var(--color-accent); }
.nav a.active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -4px;
  height: 2px;
  background: var(--color-accent);
  border-radius: 2px;
}
.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.4rem 0.6rem;
  cursor: pointer;
  font-size: 1rem;
}

.hero {
  background:
    radial-gradient(1200px 600px at 80% -10%, var(--color-accent-soft), transparent 60%),
    linear-gradient(180deg, #fafbfd 0%, #ffffff 100%);
  padding: 4.5rem 0 3.5rem;
  border-bottom: 1px solid var(--color-border);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.3fr 0.9fr;
  gap: 3rem;
  align-items: center;
}
.hero-eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78rem;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 0.75rem;
}
.hero h1 { margin-bottom: 0.4rem; }
.hero .role {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  color: var(--color-text-muted);
  margin-bottom: 1.25rem;
}
.hero .mission {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 36rem;
  margin-bottom: 1.75rem;
}
.hero-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.7rem 1.15rem;
  border-radius: var(--radius-sm);
  font-weight: 500;
  font-size: 0.95rem;
  transition: transform 0.1s ease, background 0.15s ease, color 0.15s ease, box-shadow 0.15s ease;
}
.btn-primary {
  background: var(--color-accent);
  color: #fff;
  box-shadow: var(--shadow-sm);
}
.btn-primary:hover { background: var(--color-accent-dark); color: #fff; transform: translateY(-1px); }
.btn-outline {
  border: 1px solid var(--color-border);
  color: var(--color-text);
  background: #fff;
}
.btn-outline:hover { border-color: var(--color-accent); color: var(--color-accent); }

.hero-photo {
  position: relative;
  justify-self: end;
}
.hero-photo img {
  width: 320px;
  height: 320px;
  object-fit: cover;
  border-radius: 50%;
  border: 6px solid #fff;
  box-shadow: var(--shadow-lg);
}
.hero-photo::before {
  content: "";
  position: absolute;
  inset: -18px;
  border-radius: 50%;
  border: 2px dashed var(--color-accent-soft);
  z-index: -1;
}

.section { padding: 4rem 0; }
.section-alt { background: var(--color-bg-alt); }
.section-header {
  display: flex;
  align-items: end;
  justify-content: space-between;
  margin-bottom: 2rem;
  gap: 1rem;
  flex-wrap: wrap;
}
.section-eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78rem;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 0.4rem;
}
.section-title { margin: 0; }
.section-subtitle { color: var(--color-text-muted); max-width: 42rem; margin: 0.4rem 0 0; }

.cards { display: grid; gap: 1.5rem; }
.cards.cols-2 { grid-template-columns: repeat(2, 1fr); }
.cards.cols-3 { grid-template-columns: repeat(3, 1fr); }
.cards.cols-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
  display: flex;
  flex-direction: column;
  height: 100%;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: #d8e0ee;
}
.card h3 { margin: 0.3rem 0 0.5rem; font-size: 1.15rem; }
.card p { color: var(--color-text-muted); font-size: 0.95rem; }
.card .meta {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 0.5rem;
}
.card .tags {
  margin-top: auto;
  padding-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.tag {
  font-size: 0.74rem;
  background: var(--color-accent-tint);
  color: var(--color-accent-dark);
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  font-weight: 500;
}

.news-list { display: grid; gap: 1rem; }
.news-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 1.25rem;
  padding: 1.1rem 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #fff;
}
.news-date {
  font-family: var(--font-serif);
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.95rem;
}
.news-item h4 { margin: 0 0 0.25rem; }
.news-item p { margin: 0; color: var(--color-text-muted); font-size: 0.95rem; }

.area-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }
.area {
  background: #fff;
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-accent);
  padding: 1rem 1.1rem;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  color: var(--color-text);
  transition: background 0.15s ease, transform 0.15s ease;
}
.area:hover { background: var(--color-accent-tint); transform: translateY(-2px); }
.area strong { display: block; margin-bottom: 0.2rem; color: var(--color-text); }
.area span { color: var(--color-text-muted); font-size: 0.85rem; }

.pub-list, .feature-list { display: grid; gap: 1.25rem; }
.pub-item, .feature-item {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
}
.pub-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 1.1rem;
  margin: 0 0 0.35rem;
  color: var(--color-text);
}
.pub-authors { color: var(--color-text-muted); font-size: 0.9rem; margin: 0 0 0.25rem; }
.pub-venue { color: var(--color-text-soft); font-size: 0.85rem; font-style: italic; margin: 0; }

.feature-item {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 1.5rem;
  align-items: center;
}
.feature-thumb {
  width: 100%;
  aspect-ratio: 4/3;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-accent-soft), var(--color-accent-tint));
  display: grid;
  place-items: center;
  color: var(--color-accent-dark);
  font-family: var(--font-serif);
  font-size: 1.6rem;
  font-weight: 600;
  border: 1px solid var(--color-border);
  text-align: center;
  padding: 1rem;
}

.about-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.4fr;
  gap: 3rem;
  align-items: start;
}
.about-card {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}
.about-card img {
  width: 100%;
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}
.about-card h3 { margin-top: 0; }
.about-meta { display: grid; gap: 0.5rem; font-size: 0.95rem; }
.about-meta strong { color: var(--color-text); }
.about-meta span { color: var(--color-text-muted); }

.prose p { color: var(--color-text); }
.prose p + p { margin-top: 0.6em; }
.prose h2 { margin-top: 2rem; }

.cta-strip {
  background: linear-gradient(120deg, var(--color-accent-dark), var(--color-accent));
  color: #fff;
  padding: 3rem 0;
  text-align: center;
}
.cta-strip h2 { color: #fff; }
.cta-strip p { color: #d6e0f5; max-width: 36rem; margin: 0.5rem auto 1.5rem; }
.cta-strip .btn-primary { background: #fff; color: var(--color-accent-dark); }
.cta-strip .btn-primary:hover { background: #e6edfb; }

.site-footer {
  background: #0f172a;
  color: #c8d1e4;
  padding: 3rem 0 1.5rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}
.site-footer h4 {
  color: #fff;
  margin-bottom: 0.85rem;
  font-size: 1rem;
  font-family: var(--font-sans);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.site-footer a { color: #c8d1e4; }
.site-footer a:hover { color: #fff; }
.site-footer ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.4rem; font-size: 0.95rem; }
.footer-bottom {
  border-top: 1px solid #1f2a44;
  padding-top: 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: #8593ad;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.social-row { display: flex; gap: 0.6rem; }
.social-row a {
  display: inline-grid;
  place-items: center;
  width: 36px; height: 36px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
  font-size: 0.95rem;
  transition: background 0.15s ease;
}
.social-row a:hover { background: var(--color-accent); }

.form-grid { display: grid; gap: 1rem; max-width: 36rem; }
.form-grid input,
.form-grid textarea {
  width: 100%;
  padding: 0.75rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.95rem;
  background: #fff;
  color: var(--color-text);
}
.form-grid textarea { min-height: 140px; resize: vertical; }
.form-grid input:focus,
.form-grid textarea:focus {
  outline: 2px solid var(--color-accent-soft);
  border-color: var(--color-accent);
}

.page-header {
  background: var(--color-bg-alt);
  border-bottom: 1px solid var(--color-border);
  padding: 3rem 0 2.25rem;
}
.page-header h1 { margin-bottom: 0.25rem; }
.page-header p { color: var(--color-text-muted); margin: 0; max-width: 42rem; }

@media (max-width: 960px) {
  .hero-grid { grid-template-columns: 1fr; text-align: left; }
  .hero-photo { justify-self: start; }
  .hero-photo img { width: 240px; height: 240px; }
  .cards.cols-3, .cards.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .area-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-item { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .nav { display: none; position: absolute; top: var(--header-height); left: 0; right: 0; background: #fff; flex-direction: column; padding: 1rem 1.5rem; border-bottom: 1px solid var(--color-border); align-items: flex-start; }
  .nav.open { display: flex; }
  .nav-toggle { display: inline-flex; }
}
@media (max-width: 600px) {
  .cards.cols-2, .cards.cols-3, .cards.cols-4 { grid-template-columns: 1fr; }
  .area-grid { grid-template-columns: 1fr; }
  .news-item { grid-template-columns: 1fr; gap: 0.25rem; }
  .footer-grid { grid-template-columns: 1fr; }
  .topbar { display: none; }
}