/* ============================================================
   STYLE.CSS — Rajpal Singh Personal Site
   ============================================================
   Table of Contents:
   1. Variables & Reset
   2. Base Typography
   3. Navigation
   4. Layout & Sections
   5. Hero
   6. Research Interests Grid
   7. News
   8. Publications
   9. Education
   10. Teaching
   11. Contact
   12. Footer & Back-to-Top
   13. Animations
   14. Responsive
   ============================================================ */


/* ── 1. VARIABLES & RESET ── */

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

:root {
  --bg:           #f9f7f4;
  --surface:      #ffffff;
  --ink:          #1a1917;
  --ink-2:        #4a4845;
  --ink-3:        #7a7875;
  --accent:       #1a3a5c;
  --accent-light: #e8eef5;
  --rule:         #e0ddd8;
  --tag-bg:       #f0ece6;

  --serif: 'EB Garamond', Georgia, serif;
  --mono:  'DM Mono', 'Courier New', monospace;

  --max:   860px;
  --nav-h: 60px;
}


/* ── 2. BASE TYPOGRAPHY ── */

html {
  scroll-behavior: smooth;
  font-size: 17px;
}

body {
  background:  var(--bg);
  color:       var(--ink);
  font-family: var(--serif);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

strong {
  font-weight: 600;
}

em {
  font-style: italic;
}


/* ── 3. NAVIGATION ── */

nav {
  position:   fixed;
  top: 0; left: 0; right: 0;
  z-index:    100;
  height:     var(--nav-h);
  background: rgba(249, 247, 244, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
  display:    flex;
  align-items: center;
}

.nav-inner {
  max-width: var(--max);
  margin:    0 auto;
  padding:   0 2rem;
  width:     100%;
  display:   flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--serif);
  font-size:   1rem;
  font-weight: 500;
  color:       var(--ink);
  text-decoration: none;
  letter-spacing: 0.01em;
}

.nav-links {
  display:   flex;
  gap:       2rem;
  list-style: none;
}

.nav-links a {
  font-family:     var(--mono);
  font-size:       0.72rem;
  font-weight:     400;
  color:           var(--ink-2);
  text-decoration: none;
  letter-spacing:  0.08em;
  text-transform:  uppercase;
  transition:      color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
}

/* Hamburger (mobile) — hidden on desktop */
.nav-toggle {
  display:    none;
  background: none;
  border:     none;
  cursor:     pointer;
  padding:    4px;
  color:      var(--ink);
  font-size:  1.3rem;
}


/* ── 4. LAYOUT & SECTIONS ── */

main {
  max-width: var(--max);
  margin:    0 auto;
  padding:   calc(var(--nav-h) + 4rem) 2rem 4rem;
}

section {
  margin-bottom: 5rem;
}

/* Section heading: title + horizontal rule */
.section-heading {
  display:     flex;
  align-items: baseline;
  gap:         1rem;
  margin-bottom: 2rem;
}

.section-heading h2 {
  font-size:      1.55rem;
  font-weight:    500;
  letter-spacing: -0.005em;
  white-space:    nowrap;
}

.section-heading .rule {
  flex:       1;
  height:     1px;
  background: var(--rule);
  margin-bottom: 3px;
}


/* ── 5. HERO ── */

.hero {
  display: grid;
  grid-template-columns: 1fr 180px;
  gap:         3rem;
  align-items: start;
  padding-bottom: 4rem;
  border-bottom:  1px solid var(--rule);
  margin-bottom:  5rem;
}

.hero-text h1 {
  font-size:      2.6rem;
  font-weight:    500;
  line-height:    1.15;
  margin-bottom:  0.4rem;
  letter-spacing: -0.01em;
}

.hero-text .title-line {
  font-family:    var(--mono);
  font-size:      0.75rem;
  color:          var(--accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom:  1.4rem;
  font-weight:    400;
}

.hero-text p {
  color:       var(--ink-2);
  font-size:   1rem;
  max-width:   560px;
  line-height: 1.75;
  margin-bottom: 1rem;
}

/* Quick-link buttons under the bio */
.hero-links {
  display:     flex;
  flex-wrap:   wrap;
  gap:         0.6rem;
  margin-top:  1.6rem;
}

.hero-link {
  display:     inline-flex;
  align-items: center;
  gap:         0.4em;
  font-family: var(--mono);
  font-size:   0.7rem;
  font-weight: 400;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color:       var(--ink-2);
  text-decoration: none;
  border:      1px solid var(--rule);
  padding:     0.4em 0.85em;
  border-radius: 2px;
  background:  var(--surface);
  transition:  all 0.2s;
}

.hero-link:hover {
  border-color: var(--accent);
  color:        var(--accent);
  background:   var(--accent-light);
  text-decoration: none;
}

.hero-link svg {
  width:      12px;
  height:     12px;
  flex-shrink: 0;
}

/* Profile photo */
.hero-photo {
  width:         180px;
  height:        180px;
  border-radius: 4px;
  overflow:      hidden;
  box-shadow:    0 2px 20px rgba(0, 0, 0, 0.10);
  flex-shrink:   0;
}

.hero-photo img {
  width:      100%;
  height:     100%;
  object-fit: cover;
  display:    block;
}

/* Fallback if image fails to load */
.hero-photo-placeholder {
  width:       100%;
  height:      100%;
  background:  var(--accent-light);
  display:     flex;
  align-items: center;
  justify-content: center;
  color:       var(--accent);
  font-family: var(--mono);
  font-size:   0.65rem;
  text-align:  center;
  padding:     1rem;
  letter-spacing: 0.05em;
}


/* ── 6. RESEARCH INTERESTS GRID ── */

.interests-grid {
  display:    grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap:        1px;
  border:     1px solid var(--rule);
  background: var(--rule);
  border-radius: 3px;
  overflow:   hidden;
}

.interest-card {
  background: var(--surface);
  padding:    1.3rem 1.4rem;
}

.interest-card .ic-num {
  font-family:    var(--mono);
  font-size:      0.62rem;
  color:          var(--ink-3);
  letter-spacing: 0.08em;
  margin-bottom:  0.5rem;
  display:        block;
}

.interest-card h3 {
  font-size:     0.92rem;
  font-weight:   500;
  margin-bottom: 0.3rem;
}

.interest-card p {
  font-size:   0.82rem;
  color:       var(--ink-2);
  line-height: 1.5;
}


/* ── 7. NEWS ── */

.news-list {
  list-style: none;
}

.news-item {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap:          1rem;
  padding:      0.8rem 0;
  border-bottom: 1px solid var(--rule);
  font-size:    0.9rem;
}

.news-item:last-child {
  border-bottom: none;
}

.news-date {
  font-family:    var(--mono);
  font-size:      0.65rem;
  color:          var(--ink-3);
  letter-spacing: 0.05em;
  padding-top:    0.18rem;
}

.news-text {
  color:       var(--ink-2);
  line-height: 1.55;
}


/* ── 8. PUBLICATIONS ── */

.pub-group {
  margin-bottom: 2.5rem;
}

.pub-group-label {
  font-family:    var(--mono);
  font-size:      0.65rem;
  color:          var(--ink-3);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom:  1rem;
  padding-bottom: 0.5rem;
  border-bottom:  1px solid var(--rule);
}

.pub-item {
  padding:       1.3rem 0;
  border-bottom: 1px solid var(--rule);
  display:       grid;
  gap:           0.3rem;
}

.pub-item:last-child {
  border-bottom: none;
}

.pub-title {
  font-size:   1rem;
  font-weight: 500;
  color:       var(--ink);
  line-height: 1.4;
  font-style:  italic;
}

.pub-authors {
  font-size: 0.85rem;
  color:     var(--ink-2);
}

.pub-venue {
  font-family:    var(--mono);
  font-size:      0.68rem;
  color:          var(--accent);
  letter-spacing: 0.04em;
}

.pub-links {
  display:   flex;
  flex-wrap: wrap;
  gap:       0.5rem;
  margin-top: 0.4rem;
}

.pub-link {
  font-family:     var(--mono);
  font-size:       0.64rem;
  letter-spacing:  0.06em;
  text-transform:  uppercase;
  color:           var(--ink-3);
  text-decoration: none;
  border:          1px solid var(--rule);
  padding:         0.2em 0.6em;
  border-radius:   2px;
  background:      var(--surface);
  transition:      all 0.18s;
}

.pub-link:hover {
  color:      var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
  text-decoration: none;
}

/* Small badge e.g. "ICRA 2026" or "New" */
.pub-badge {
  display:        inline-block;
  font-family:    var(--mono);
  font-size:      0.6rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background:     var(--accent);
  color:          #fff;
  padding:        0.15em 0.55em;
  border-radius:  2px;
  vertical-align: middle;
  margin-left:    0.4em;
}

/* ── 9. PROJECTS (ACCORDION) ── */

.project-list { list-style: none; }

.project-item {
  border-bottom: 1px solid var(--rule);
}

.project-item:first-child {
  border-top: 1px solid var(--rule);
}

/* Clickable header row */
.project-header {
  display:     flex;
  align-items: center;
  justify-content: space-between;
  gap:         1rem;
  padding:     1.1rem 0;
  cursor:      pointer;
  user-select: none;
  list-style:  none;
}

.project-header:hover .project-title { color: var(--accent); }

.project-header-left { display: flex; align-items: baseline; gap: 1rem; flex: 1; }

.project-year {
  font-family:    var(--mono);
  font-size:      0.65rem;
  color:          var(--ink-3);
  letter-spacing: 0.05em;
  white-space:    nowrap;
  flex-shrink:    0;
  padding-top:    0.1rem;
}

.project-title {
  font-size:   1rem;
  font-weight: 500;
  line-height: 1.35;
  color:       var(--ink);
  transition:  color 0.2s;
}

/* Chevron icon */
.project-chevron {
  flex-shrink: 0;
  width:       18px;
  height:      18px;
  color:       var(--ink-3);
  transition:  transform 0.3s ease;
}

.project-item.open .project-chevron {
  transform: rotate(180deg);
  color:     var(--accent);
}

/* Collapsible body */
.project-body {
  max-height: 0;
  overflow:   hidden;
  transition: max-height 0.35s ease;
}

.project-body-inner {
  padding: 0 0 1.4rem 0;
  display: grid;
  gap:     0.9rem;
}

.project-desc {
  font-size:   0.92rem;
  color:       var(--ink-2);
  line-height: 1.7;
}

/* Bullet points inside description */
.project-desc ul {
  margin:     0.4rem 0 0 1.2rem;
  display:    grid;
  gap:        0.3rem;
}

.project-desc ul li {
  font-size:   0.88rem;
  color:       var(--ink-2);
  line-height: 1.6;
}

/* Status tag e.g. "Ongoing" */
.project-status {
  display:        inline-block;
  font-family:    var(--mono);
  font-size:      0.6rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  padding:        0.15em 0.6em;
  border-radius:  2px;
  margin-left:    0.5em;
  vertical-align: middle;
}

.project-status.ongoing {
  background: #e6f4ea;
  color:      #276749;
}

.project-status.completed {
  background: var(--tag-bg);
  color:      var(--ink-3);
}

/* Link buttons — same style as pub-link */
.project-links { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.project-link {
  font-family:     var(--mono);
  font-size:       0.64rem;
  letter-spacing:  0.06em;
  text-transform:  uppercase;
  color:           var(--ink-3);
  text-decoration: none;
  border:          1px solid var(--rule);
  padding:         0.25em 0.7em;
  border-radius:   2px;
  background:      var(--surface);
  transition:      all 0.18s;
  display:         inline-flex;
  align-items:     center;
  gap:             0.35em;
}

.project-link:hover {
  color:           var(--accent);
  border-color:    var(--accent);
  background:      var(--accent-light);
  text-decoration: none;
}

.project-link svg { width: 11px; height: 11px; flex-shrink: 0; }

/* ── 9. EDUCATION ── */

.edu-list {
  list-style: none;
}

.edu-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap:          1rem;
  padding:      1rem 0;
  border-bottom: 1px solid var(--rule);
}

.edu-item:last-child {
  border-bottom: none;
}

.edu-year {
  font-family:    var(--mono);
  font-size:      0.68rem;
  color:          var(--ink-3);
  letter-spacing: 0.05em;
  padding-top:    0.2rem;
}

.edu-body h3 {
  font-size:     0.95rem;
  font-weight:   500;
  margin-bottom: 0.1rem;
}

.edu-body p {
  font-size: 0.84rem;
  color:     var(--ink-2);
}


/* ── 10. TEACHING ── */

.teaching-list {
  list-style: none;
}

.teaching-item {
  padding:       1rem 0;
  border-bottom: 1px solid var(--rule);
}

.teaching-item:last-child {
  border-bottom: none;
}

.teaching-item h3 {
  font-size:     0.95rem;
  font-weight:   500;
  margin-bottom: 0.2rem;
}

.teaching-item p {
  font-size: 0.84rem;
  color:     var(--ink-2);
}

.teaching-tag {
  display:        inline-block;
  font-family:    var(--mono);
  font-size:      0.6rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background:     var(--tag-bg);
  color:          var(--ink-3);
  padding:        0.15em 0.55em;
  border-radius:  2px;
  margin-bottom:  0.4rem;
}


/* ── 11. CONTACT ── */

.contact-block {
  background:    var(--surface);
  border:        1px solid var(--rule);
  border-radius: 3px;
  padding:       2rem 2.2rem;
  display:       grid;
  grid-template-columns: 1fr 1fr;
  gap:           1.5rem 3rem;
}

.contact-item {
  display:        flex;
  flex-direction: column;
  gap:            0.2rem;
}

.contact-label {
  font-family:    var(--mono);
  font-size:      0.62rem;
  color:          var(--ink-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.contact-value {
  font-size: 0.9rem;
  color:     var(--ink-2);
}


/* ── 12. FOOTER & BACK-TO-TOP ── */

footer {
  border-top:  1px solid var(--rule);
  padding:     2rem;
  text-align:  center;
  font-family: var(--mono);
  font-size:   0.65rem;
  color:       var(--ink-3);
  letter-spacing: 0.06em;
  max-width:   var(--max);
  margin:      0 auto;
}

.back-top {
  position:    fixed;
  bottom:      2rem;
  right:       2rem;
  width:       36px;
  height:      36px;
  background:  var(--surface);
  border:      1px solid var(--rule);
  border-radius: 2px;
  cursor:      pointer;
  display:     flex;
  align-items: center;
  justify-content: center;
  font-size:   0.9rem;
  color:       var(--ink-3);
  text-decoration: none;
  transition:  all 0.2s;
  opacity:     0;
  pointer-events: none;
}

.back-top.visible {
  opacity:        1;
  pointer-events: auto;
}

.back-top:hover {
  border-color:    var(--accent);
  color:           var(--accent);
  text-decoration: none;
}


/* ── 13. ANIMATIONS ── */

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

.hero              { animation: fadeUp 0.7s ease both; }
.section-heading   { animation: fadeUp 0.6s ease both 0.1s; }


/* ── 14. RESPONSIVE ── */

@media (max-width: 640px) {
  .nav-links {
    display:        none;
    flex-direction: column;
    gap:            0;
    position:       absolute;
    top:            var(--nav-h);
    left:           0; right: 0;
    background:     var(--bg);
    border-bottom:  1px solid var(--rule);
    padding:        1rem 2rem;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--rule);
  }

  .nav-links li:last-child {
    border-bottom: none;
  }

  .nav-toggle {
    display: block;
  }

  .hero {
    grid-template-columns: 1fr;
  }

  .hero-photo {
    width:  120px;
    height: 120px;
    order:  -1;
  }

  .hero-text h1 {
    font-size: 2rem;
  }

  .interests-grid {
    grid-template-columns: 1fr 1fr;
  }

  .news-item,
  .edu-item {
    grid-template-columns: 1fr;
    gap: 0.2rem;
  }

  .contact-block {
    grid-template-columns: 1fr;
  }

  .pub-authors {
    font-size: 0.8rem;
  }
}
/* ── NEWS SCROLL ── */
.news-list-wrapper {
  max-height: 340px;
  overflow-y: auto;
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 0 1.2rem;
  scroll-behavior: smooth;
}

.news-list-wrapper::-webkit-scrollbar {
  width: 4px;
}

.news-list-wrapper::-webkit-scrollbar-track {
  background: var(--tag-bg);
}

.news-list-wrapper::-webkit-scrollbar-thumb {
  background: var(--rule);
  border-radius: 2px;
}

.news-list-wrapper::-webkit-scrollbar-thumb:hover {
  background: var(--ink-3);
}