/* ==========================================================================
   GLOBAL STYLES & CORE PALETTE
   ========================================================================== */
:root {
  --bg-main: #0b0f17;
  --bg-card: #131b2e;
  --bg-alt: #0e1422;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --accent-blue: #2563eb;
  --accent-glow: #38bdf8;
  --accent-cyan: #06b6d4;
  --border-color: rgba(56, 189, 248, 0.15);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
}

/* NAVBAR */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 40px;
  background: rgba(11, 15, 23, 0.85);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid var(--border-color);
}

.nav-brand {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 1px;
  color: #fff;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 25px;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.3s ease;
}

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

/* HERO / INTRO SECTION */
.intro {
  position: relative;
  padding: 100px 20px 80px 20px;
  text-align: center;
  background: radial-gradient(circle at 50% 20%, rgba(37, 99, 235, 0.15) 0%, transparent 60%), var(--bg-main);
  border-bottom: 1px solid var(--border-color);
  overflow: hidden;
}

.intro-content {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

.intro h1 {
  font-size: 2.8rem;
  margin-bottom: 8px;
}

.highlight {
  color: var(--accent-glow);
  text-shadow: 0 0 12px rgba(56, 189, 248, 0.4);
}

.intro h2 {
  font-size: 1.2rem;
  color: var(--text-muted);
  font-weight: 400;
  margin-bottom: 20px;
}

.intro p {
  font-size: 1.05rem;
  color: #cbd5e1;
  margin-bottom: 30px;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-bottom: 25px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: 6px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.3s ease;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-blue), #1d4ed8);
  color: #fff;
  box-shadow: 0 0 15px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
  box-shadow: 0 0 25px rgba(56, 189, 248, 0.6);
  transform: translateY(-2px);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: rgba(56, 189, 248, 0.1);
  border-color: var(--accent-glow);
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 20px;
}

.social-links a {
  color: var(--text-muted);
  font-size: 1.4rem;
  transition: color 0.3s ease, transform 0.3s ease;
}

.social-links a:hover {
  color: var(--accent-glow);
  transform: translateY(-3px);
}

/* PROJECT SECTIONS & HORIZONTAL SCROLL */
.project-section {
  padding: 70px 40px;
}

.project-section.alt {
  background-color: var(--bg-alt);
}

.section-header {
  max-width: 800px;
  margin-bottom: 10px;
}

.section-header h2 {
  font-size: 1.8rem;
  margin: 0;
  color: #fff;
  border-left: 4px solid var(--accent-blue);
  padding-left: 12px;
}

.section-subtitle {
  color: var(--text-muted);
  margin-top: 5px;
  font-size: 0.95rem;
}

.scroll-hint {
  font-size: 0.85rem;
  color: var(--accent-glow);
  margin-bottom: 15px;
}

.scroll-container {
  display: flex;
  overflow-x: auto;
  gap: 24px;
  padding: 10px 0 25px 0;
  scroll-snap-type: x mandatory;
}

.scroll-container::-webkit-scrollbar {
  height: 8px;
}

.scroll-container::-webkit-scrollbar-track {
  background: var(--bg-main);
  border-radius: 4px;
}

.scroll-container::-webkit-scrollbar-thumb {
  background: #1e293b;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* PROJECT CARD */
.project-card {
  min-width: 320px;
  max-width: 340px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  overflow: hidden;
  scroll-snap-align: start;
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
}

.project-card:hover {
  transform: translateY(-6px);
  border-color: var(--accent-glow);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4), 0 0 15px rgba(56, 189, 248, 0.2);
}

.card-image {
  position: relative;
  width: 100%;
  height: 180px;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  cursor: pointer;
  transition: opacity 0.2s ease-in-out;
}

.badge {
  position: absolute;
  top: 10px;
  right: 10px;
  padding: 3px 8px;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 4px;
  text-transform: uppercase;
  z-index: 5;
}

.badge.team { background: #1e3a8a; color: #93c5fd; }
.badge.solo { background: #065f46; color: #a7f3d0; }
.badge.academic { background: #581c87; color: #e9d5ff; }

.card-content {
  padding: 18px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.card-content h3 {
  margin: 0 0 4px 0;
  font-size: 1.1rem;
  color: #fff;
}

.card-content .role {
  font-size: 0.85rem;
  color: var(--accent-glow);
  margin: 0 0 10px 0;
  font-weight: 600;
}

.card-content .desc {
  font-size: 0.88rem;
  color: #cbd5e1;
  margin-bottom: 15px;
  flex-grow: 1;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag {
  font-size: 0.75rem;
  padding: 3px 8px;
  background: rgba(30, 41, 59, 0.8);
  color: #94a3b8;
  border-radius: 4px;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

/* ==========================================================================
   SIDE ARROW NAVIGATION & MEDIA INDICATORS
   ========================================================================== */
.nav-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(15, 23, 42, 0.75);
  color: var(--accent-glow);
  border: 1px solid var(--border-color);
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  cursor: pointer;
  z-index: 10;
  backdrop-filter: blur(4px);
  opacity: 0.8;
  transition: all 0.2s ease;
}

.card-image:hover .nav-arrow {
  opacity: 1;
}

.nav-arrow:hover {
  background: var(--accent-blue);
  color: #ffffff;
  transform: translateY(-50%) scale(1.1);
}

.left-arrow { left: 8px; }
.right-arrow { right: 8px; }

.media-indicator {
  position: absolute;
  bottom: 8px;
  left: 8px;
  background: rgba(15, 23, 42, 0.85);
  color: #cbd5e1;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
  z-index: 5;
  backdrop-filter: blur(4px);
}

.video-link-btn {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(15, 23, 42, 0.85);
  color: var(--accent-glow);
  text-decoration: none;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 3px 9px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
  z-index: 5;
  backdrop-filter: blur(4px);
  transition: all 0.2s ease;
}

.video-link-btn:hover {
  background: var(--accent-blue);
  color: #fff;
}

/* ==========================================================================
   CONTACT SECTION
   ========================================================================== */
.contact {
  padding: 80px 20px;
  background: var(--bg-main);
  border-top: 1px solid var(--border-color);
}

.contact-container {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.contact h2 {
  font-size: 2rem;
  margin-bottom: 8px;
}

.contact p {
  color: var(--text-muted);
  margin-bottom: 30px;
}

form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.form-row {
  display: flex;
  gap: 12px;
}

.form-row input {
  flex: 1;
}

input, textarea {
  padding: 12px 14px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-card);
  color: white;
  font-size: 0.95rem;
}

input:focus, textarea:focus {
  outline: none;
  border-color: var(--accent-glow);
  box-shadow: 0 0 10px rgba(56, 189, 248, 0.3);
}

.footer-bottom {
  margin-top: 40px;
  font-size: 0.85rem;
  color: #64748b;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 20px;
}

/* LIGHTBOX MODAL */
.lightbox {
  display: none;
  position: fixed;
  z-index: 2000;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-color: rgba(11, 15, 23, 0.95);
  backdrop-filter: blur(10px);
  justify-content: center;
  align-items: center;
  flex-direction: column;
  animation: fadeIn 0.25s ease-out;
}

.lightbox-content {
  max-width: 90%;
  max-height: 85vh;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  box-shadow: 0 0 30px rgba(56, 189, 248, 0.3);
  object-fit: contain;
}

#lightbox-caption {
  margin-top: 15px;
  color: var(--text-muted);
  font-size: 0.95rem;
  letter-spacing: 0.5px;
}

.lightbox-close {
  position: absolute;
  top: 20px;
  right: 35px;
  color: #fff;
  font-size: 38px;
  font-weight: bold;
  cursor: pointer;
  transition: color 0.2s ease;
}

.lightbox-close:hover {
  color: var(--accent-glow);
}

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