/* =====================================
   DR. BHARGAV REDDY ISANAKA
   Academic Website – Main Stylesheet
===================================== */

:root {
  --primary: #153653;
  --secondary: #2878a8;
  --accent: #d9a441;
  --text: #293746;
  --muted: #687887;
  --background: #ffffff;
  --light-bg: #f3f6f9;
  --border: #e1e7ed;
  --max-width: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", "Segoe UI", Arial, sans-serif;
  color: var(--text);
  background: var(--background);
  line-height: 1.7;
  font-size: 16px;
}

a {
  color: var(--secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--primary);
}

/* Header and navigation */

.site-header {
  background: #ffffff;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--max-width);
  margin: auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.site-name {
  color: var(--primary);
  font-size: 19px;
  font-weight: 700;
  white-space: nowrap;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 21px;
}

.main-nav a,
.dropdown-label {
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}

.main-nav a:hover,
.dropdown-label:hover {
  color: var(--secondary);
}

.dropdown {
  position: relative;
}

.dropdown-content {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 205px;
  padding: 10px 0;
  background: white;
  border: 1px solid var(--border);
  border-radius: 6px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.09);
}

.dropdown:hover .dropdown-content,
.dropdown:focus-within .dropdown-content {
  display: block;
}

.dropdown-content a {
  display: block;
  padding: 8px 16px;
}

/* Main content */

main {
  min-height: 65vh;
}

.page-container {
  max-width: var(--max-width);
  margin: auto;
  padding: 55px 24px 75px;
}

.page-title {
  color: var(--primary);
  font-size: 34px;
  line-height: 1.25;
  margin: 0 0 12px;
}

.page-intro {
  color: var(--muted);
  font-size: 17px;
  margin-bottom: 35px;
}

h1, h2, h3, h4 {
  color: var(--primary);
  line-height: 1.35;
}

h2 {
  font-size: 25px;
  margin-top: 38px;
}

h3 {
  font-size: 19px;
}

p {
  margin: 0 0 17px;
}

ul, ol {
  padding-left: 24px;
}

li {
  margin-bottom: 8px;
}

/* Section styling */

.section {
  padding: 48px 24px;
}

.section-inner {
  max-width: var(--max-width);
  margin: auto;
}

.section-light {
  background: var(--light-bg);
}

.section-heading {
  font-size: 27px;
  margin: 0 0 25px;
  color: var(--primary);
}

.section-heading::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  background: var(--accent);
  margin-top: 12px;
}

/* Cards */

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 22px;
}

.card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.07);
}

.card h3 {
  margin-top: 0;
}

/* Research and publication entries */

.entry {
  padding: 22px 0;
  border-bottom: 1px solid var(--border);
}

.entry:last-child {
  border-bottom: none;
}

.entry h3 {
  margin: 0 0 8px;
}

.entry-meta {
  color: var(--muted);
  font-size: 14px;
}

/* Buttons */

.button {
  display: inline-block;
  background: var(--primary);
  color: #ffffff;
  padding: 11px 22px;
  border-radius: 5px;
  font-weight: 600;
}

.button:hover {
  background: var(--secondary);
  color: #ffffff;
}

/* Footer */

.site-footer {
  background: #102b43;
  color: #dce6ee;
  text-align: center;
  padding: 38px 24px 22px;
}

.site-footer h3 {
  color: #ffffff;
  margin-top: 0;
}

.site-footer p {
  color: #dce6ee;
}

.footer-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 22px;
  margin: 20px 0;
}

.footer-links a {
  color: #ffffff;
  font-size: 14px;
}

.footer-links a:hover {
  color: var(--accent);
}

.copyright {
  font-size: 13px;
  margin-top: 25px;
  opacity: 0.8;
}

/* Images */

img {
  max-width: 100%;
  height: auto;
}

.profile-image {
  width: 230px;
  height: 270px;
  object-fit: cover;
  border-radius: 8px;
}

/* Responsive layout */

@media (max-width: 900px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav {
    flex-wrap: wrap;
    gap: 12px 18px;
  }
}

@media (max-width: 600px) {
  .header-inner {
    padding: 14px 18px;
  }

  .site-name {
    font-size: 17px;
  }

  .main-nav {
    gap: 10px 14px;
  }

  .main-nav a,
  .dropdown-label {
    font-size: 13px;
  }

  .page-container {
    padding: 35px 18px 50px;
  }

  .page-title {
    font-size: 28px;
  }

  .section {
    padding: 35px 18px;
  }

  .section-heading {
    font-size: 23px;
  }
}