/* ===========================
   BHAVINI JELOKA — ACADEMIC PORTFOLIO
   Design System & Global Styles
   =========================== */

@import url('https://fonts.googleapis.com/css2?family=Lora:ital,wght@0,400;0,500;0,600;0,700;1,400;1,500&family=Inter:wght@300;400;500;600;700&display=swap');

/* ─── CSS Variables ─── */
:root {
  --ivory:        #FAF8F3;
  --ivory-dark:   #F2EDE3;
  --ivory-mid:    #EDE8DC;
  --terracotta:   #C4704F;
  --terracotta-lt:#D8886A;
  --terracotta-dk:#A85C3E;
  --sage:         #7A9E7E;
  --sage-lt:      #A8C5AB;
  --sage-dk:      #5C7E60;
  --charcoal:     #2C2826;
  --charcoal-md:  #4A4340;
  --charcoal-lt:  #7A7270;
  --warm-white:   #FFFDF9;
  --border:       #E4DDD2;
  --shadow-sm:    0 2px 8px rgba(44,40,38,0.08);
  --shadow-md:    0 8px 24px rgba(44,40,38,0.12);
  --shadow-lg:    0 16px 48px rgba(44,40,38,0.16);
  --radius-sm:    6px;
  --radius-md:    12px;
  --radius-lg:    20px;
  --transition:   0.25s ease;
  --font-serif:   'Lora', Georgia, serif;
  --font-sans:    'Inter', system-ui, sans-serif;
}

/* ─── Reset & Base ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--ivory);
  color: var(--charcoal);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: var(--terracotta); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--terracotta-dk); }

/* ─── Typography ─── */
h1, h2, h3, h4 {
  font-family: var(--font-serif);
  line-height: 1.25;
  color: var(--charcoal);
}

h1 { font-size: clamp(2rem, 4vw, 3rem); font-weight: 700; }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 600; }
h3 { font-size: 1.25rem; font-weight: 600; }
h4 { font-size: 1rem; font-weight: 500; }

p { margin-bottom: 1rem; color: var(--charcoal-md); }
p:last-child { margin-bottom: 0; }

.serif { font-family: var(--font-serif); }
.italic { font-style: italic; }

/* ─── Layout Helpers ─── */
.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 2rem;
}

.container--wide {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

section { padding: 5rem 0; }

/* ─── Section Headers ─── */
.section-label {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--terracotta);
  margin-bottom: 0.75rem;
}

.section-header {
  margin-bottom: 3rem;
}

.section-header h2 {
  margin-bottom: 0.5rem;
}

.section-header p {
  font-size: 1.05rem;
  max-width: 56ch;
}

/* ─── Divider ─── */
.divider {
  width: 48px;
  height: 3px;
  background: linear-gradient(90deg, var(--terracotta), var(--sage));
  border-radius: 99px;
  margin: 1rem 0 1.5rem;
}

/* ─── ==================== ─── */
/*  NAVIGATION                  */
/* ─── ==================== ─── */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1rem 0;
  background: rgba(250, 248, 243, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.nav.scrolled {
  border-color: var(--border);
  box-shadow: var(--shadow-sm);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 980px;
  margin: 0 auto;
  padding: 0 2rem;
}

.nav__logo {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--charcoal);
  letter-spacing: -0.01em;
}

.nav__logo span {
  color: var(--terracotta);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav__links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--charcoal-md);
  transition: color var(--transition);
  position: relative;
}

.nav__links a::after {
  content: '';
  position: absolute;
  bottom: -3px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--terracotta);
  border-radius: 99px;
  transition: width var(--transition);
}

.nav__links a:hover {
  color: var(--terracotta);
}

.nav__links a:hover::after,
.nav__links a.active::after {
  width: 100%;
}

.nav__links a.active {
  color: var(--terracotta);
}

.nav__cta {
  padding: 0.45rem 1.1rem;
  background: var(--terracotta);
  color: var(--warm-white) !important;
  border-radius: 99px;
  font-size: 0.88rem;
  font-weight: 600;
  transition: background var(--transition), transform var(--transition) !important;
}

.nav__cta:hover {
  background: var(--terracotta-dk) !important;
  transform: translateY(-1px);
}

.nav__cta::after { display: none !important; }

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
}

.nav__toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--charcoal);
  border-radius: 99px;
  transition: transform var(--transition), opacity var(--transition);
}

/* ─── ==================== ─── */
/*  BUTTONS                     */
/* ─── ==================== ─── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.5rem;
  border-radius: 99px;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
  text-decoration: none;
  border: none;
}

.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
.btn:active { transform: translateY(0); }

.btn--primary {
  background: var(--terracotta);
  color: var(--warm-white);
}
.btn--primary:hover { background: var(--terracotta-dk); color: var(--warm-white); }

.btn--outline {
  background: transparent;
  color: var(--terracotta);
  border: 2px solid var(--terracotta);
}
.btn--outline:hover { background: var(--terracotta); color: var(--warm-white); }

.btn--ghost {
  background: var(--ivory-mid);
  color: var(--charcoal-md);
}
.btn--ghost:hover { background: var(--ivory-dark); color: var(--charcoal); }

.btn--sm {
  padding: 0.4rem 1rem;
  font-size: 0.82rem;
}

/* ─── ==================== ─── */
/*  TAG CHIPS                   */
/* ─── ==================== ─── */
.tag {
  display: inline-block;
  padding: 0.2rem 0.65rem;
  border-radius: 99px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.tag--conference {
  background: rgba(196, 112, 79, 0.12);
  color: var(--terracotta-dk);
}
.tag--workshop {
  background: rgba(122, 158, 126, 0.15);
  color: var(--sage-dk);
}
.tag--preprint {
  background: rgba(122, 114, 112, 0.12);
  color: var(--charcoal-lt);
}
.tag--journal {
  background: rgba(90, 130, 180, 0.12);
  color: #3A6BA8;
}

/* ─── ==================== ─── */
/*  CARDS                       */
/* ─── ==================== ─── */
.card {
  background: var(--warm-white);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--terracotta-lt);
}

/* ─── ==================== ─── */
/*  FOOTER                      */
/* ─── ==================== ─── */
.footer {
  background: var(--charcoal);
  color: rgba(255,255,255,0.6);
  text-align: center;
  padding: 2.5rem 2rem;
}

.footer a { color: rgba(255,255,255,0.8); }
.footer a:hover { color: var(--terracotta-lt); }

.footer__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  max-width: 600px;
  margin: 0 auto;
}

.footer__name {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  color: rgba(255,255,255,0.9);
}

.footer__links {
  display: flex;
  gap: 1.5rem;
  font-size: 0.85rem;
}

.footer__copy {
  font-size: 0.8rem;
  margin: 0;
}

/* ─── ==================== ─── */
/*  ANIMATIONS                  */
/* ─── ==================== ─── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-8px); }
}

.animate-fade-up {
  opacity: 0;
  animation: fadeUp 0.6s ease forwards;
}

.animate-fade-up.delay-1 { animation-delay: 0.1s; }
.animate-fade-up.delay-2 { animation-delay: 0.2s; }
.animate-fade-up.delay-3 { animation-delay: 0.35s; }
.animate-fade-up.delay-4 { animation-delay: 0.5s; }

/* Scroll-triggered reveal */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ─── ==================== ─── */
/*  RESPONSIVE                  */
/* ─── ==================== ─── */
@media (max-width: 768px) {
  section { padding: 3.5rem 0; }

  .nav__toggle { display: flex; }

  .nav__links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(250, 248, 243, 0.98);
    backdrop-filter: blur(12px);
    flex-direction: column;
    padding: 1.5rem 2rem;
    gap: 1rem;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-md);
  }

  .nav__links.open { display: flex; }
  .nav__cta { display: none; }
}