/* ==========================================================================
   Subharup Biswas - Portfolio Modern Design System (Webmaster 100% Audit)
   Theme: Glassmorphism & Cyber Emerald Dark Theme
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  /* Color Palette - High Contrast Certified */
  --bg-primary: #07090e;
  --bg-secondary: #0d121f;
  --bg-surface: rgba(18, 26, 43, 0.75);
  --bg-surface-hover: rgba(28, 40, 65, 0.85);
  --glass-border: rgba(255, 255, 255, 0.12);
  --glass-border-glow: rgba(0, 255, 170, 0.4);
  
  --accent-emerald: #00ffaa;
  --accent-cyan: #38bdf8;
  --accent-indigo: #818cf8;
  --accent-gradient: linear-gradient(135deg, #00ffaa 0%, #38bdf8 50%, #818cf8 100%);
  --accent-glow: rgba(0, 255, 170, 0.25);
  
  --text-primary: #ffffff;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  
  /* Typography */
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  
  /* Layout Tokens */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --radius-full: 9999px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-glow: 0 0 35px -5px rgba(0, 255, 170, 0.2);
}

/* --------------------------------------------------------------------------
   Accessibility: Skip Link & Focus Rings
   -------------------------------------------------------------------------- */
.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  background: var(--accent-emerald);
  color: #050811;
  padding: 12px 20px;
  font-weight: 700;
  border-radius: var(--radius-sm);
  z-index: 9999;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 16px;
  outline: 3px solid var(--accent-cyan);
}

*:focus-visible {
  outline: 2px solid var(--accent-emerald);
  outline-offset: 3px;
}

/* --------------------------------------------------------------------------
   Global Reset & Base
   -------------------------------------------------------------------------- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Ambient Animated Glowing Canvas Background */
.background-animation {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  pointer-events: none;
  background: 
    radial-gradient(circle at 15% 20%, rgba(0, 255, 170, 0.08) 0%, transparent 45%),
    radial-gradient(circle at 85% 60%, rgba(56, 189, 248, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 50% 90%, rgba(129, 140, 248, 0.06) 0%, transparent 50%);
  filter: blur(40px);
}

/* --------------------------------------------------------------------------
   Header & Navigation
   -------------------------------------------------------------------------- */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: 16px 5%;
  background: rgba(7, 9, 14, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--glass-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: var(--transition);
}

.logo h1 {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.logo a {
  color: var(--text-primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo a span.highlight {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 8px;
  align-items: center;
}

nav ul li a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  transition: var(--transition);
  position: relative;
}

nav ul li a:hover,
nav ul li a.active {
  color: var(--accent-emerald);
  background: rgba(0, 255, 170, 0.12);
}

nav ul li a.active::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 2px;
  background: var(--accent-emerald);
  border-radius: 2px;
  box-shadow: 0 0 8px var(--accent-emerald);
}

/* Mobile Navigation Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--glass-border);
}

.menu-toggle .bar {
  width: 22px;
  height: 2px;
  background-color: var(--accent-emerald);
  border-radius: 2px;
  transition: var(--transition);
}

/* --------------------------------------------------------------------------
   Layout Containers
   -------------------------------------------------------------------------- */
.content {
  flex: 1;
  padding-top: 110px;
  padding-bottom: 60px;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
}

section {
  margin-bottom: 70px;
}

/* Section Headings */
h2.section-title,
.skills h2,
.certificates h2,
.projects h2,
.contact h2,
.about h2 {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
  text-align: center;
  position: relative;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 40px;
  max-width: 650px;
  margin-left: auto;
  margin-right: auto;
}

/* --------------------------------------------------------------------------
   Hero Section
   -------------------------------------------------------------------------- */
.hero {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
  padding: 40px 0 60px;
}

.hero-text {
  flex: 1;
  text-align: left;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: rgba(0, 255, 170, 0.1);
  border: 1px solid rgba(0, 255, 170, 0.3);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-emerald);
  margin-bottom: 20px;
}

.status-dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-emerald);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-emerald);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(0, 255, 170, 0.7); }
  70% { transform: scale(1); box-shadow: 0 0 0 8px rgba(0, 255, 170, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(0, 255, 170, 0); }
}

.hero-text h2 {
  font-family: var(--font-heading);
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 16px;
  letter-spacing: -1px;
}

.hero-text h2 .gradient-text {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-text p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 30px;
  max-width: 560px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-image {
  flex-shrink: 0;
  position: relative;
}

.hero-image-wrapper {
  position: relative;
  width: 280px;
  height: 280px;
  border-radius: var(--radius-lg);
  padding: 8px;
  background: linear-gradient(135deg, rgba(0, 255, 170, 0.3), rgba(56, 189, 248, 0.3));
  box-shadow: var(--shadow-glow);
  transition: var(--transition);
}

.hero-image-wrapper:hover {
  transform: translateY(-6px) scale(1.02);
}

.hero-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: calc(var(--radius-lg) - 4px);
  display: block;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  border: none;
  min-height: 44px;
}

.btn-primary {
  background: var(--accent-emerald);
  color: #050811;
  box-shadow: 0 4px 20px rgba(0, 255, 170, 0.3);
}

.btn-primary:hover {
  background: #2bffd0;
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 255, 170, 0.4);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-primary);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  transform: translateY(-2px);
}

/* --------------------------------------------------------------------------
   Cards & Glassmorphism Panels
   -------------------------------------------------------------------------- */
.glass-card {
  background: var(--bg-surface);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 24px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: var(--transition);
}

.glass-card:hover {
  background: var(--bg-surface-hover);
  border-color: var(--glass-border-glow);
  transform: translateY(-4px);
  box-shadow: 0 12px 30px -10px rgba(0, 0, 0, 0.5);
}

/* --------------------------------------------------------------------------
   Skills Section
   -------------------------------------------------------------------------- */
.skills-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.skill-card {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.skill-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background: rgba(0, 255, 170, 0.12);
  color: var(--accent-emerald);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 4px;
}

.skill-card h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 600;
}

.skill-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* --------------------------------------------------------------------------
   Certificates Page & Interactive Gallery
   -------------------------------------------------------------------------- */
.certificate-filters {
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 35px;
}

.filter-btn {
  padding: 10px 20px;
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--glass-border);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
  min-height: 40px;
}

.filter-btn:hover,
.filter-btn.active {
  background: rgba(0, 255, 170, 0.15);
  border-color: var(--accent-emerald);
  color: var(--accent-emerald);
  box-shadow: 0 0 15px rgba(0, 255, 170, 0.2);
}

.certificate-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 24px;
}

.cert-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  text-decoration: none;
  background: var(--bg-surface);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.cert-card:hover {
  border-color: var(--accent-emerald);
  transform: translateY(-6px);
  box-shadow: 0 10px 25px -5px rgba(0, 255, 170, 0.25);
}

.cert-img-wrapper {
  width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: rgba(0, 0, 0, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
  position: relative;
}

.cert-img-wrapper img {
  width: 88%;
  height: 88%;
  object-fit: contain;
  transition: transform 0.3s ease;
}

.cert-pdf-badge {
  font-size: 3.5rem;
  color: var(--accent-cyan);
  transition: transform 0.3s ease;
}

.cert-card:hover .cert-img-wrapper img,
.cert-card:hover .cert-pdf-badge {
  transform: scale(1.08);
}

.cert-info {
  margin-top: auto;
  text-align: center;
}

.cert-info h4 {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.35;
}

.cert-badge-tag {
  display: inline-block;
  font-size: 0.78rem;
  color: var(--accent-cyan);
  font-weight: 600;
  background: rgba(56, 189, 248, 0.1);
  padding: 4px 10px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(56, 189, 248, 0.2);
}

/* --------------------------------------------------------------------------
   About Me Page & Timeline
   -------------------------------------------------------------------------- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 40px;
  align-items: start;
}

.about-profile-card {
  text-align: center;
  position: sticky;
  top: 130px;
}

.about-profile-card img {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--accent-emerald);
  box-shadow: var(--shadow-glow);
  margin-bottom: 16px;
}

.about-profile-card h3 {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.about-profile-card p {
  color: var(--accent-cyan);
  font-size: 0.95rem;
  margin-bottom: 16px;
}

.tech-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.pill {
  font-size: 0.82rem;
  padding: 5px 14px;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--glass-border);
  color: var(--text-secondary);
}

.timeline {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-top: 20px;
}

.timeline-item {
  position: relative;
  padding-left: 24px;
  border-left: 2px solid var(--glass-border);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -6px;
  top: 4px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent-emerald);
  box-shadow: 0 0 8px var(--accent-emerald);
}

.timeline-item h4 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  color: var(--text-primary);
}

.timeline-item span {
  font-size: 0.85rem;
  color: var(--accent-cyan);
  display: block;
  margin-bottom: 6px;
}

/* --------------------------------------------------------------------------
   Projects Page & Showcase Cards
   -------------------------------------------------------------------------- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 28px;
}

.project-card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  height: 100%;
}

.project-banner {
  height: 180px;
  width: 100%;
  background: linear-gradient(135deg, rgba(0, 255, 170, 0.15), rgba(129, 140, 248, 0.2));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3.2rem;
  color: var(--accent-emerald);
  position: relative;
}

.project-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.project-body h3 {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.project-body p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 18px;
  flex: 1;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 22px;
}

.tag {
  font-size: 0.78rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  background: rgba(0, 255, 170, 0.1);
  color: var(--accent-emerald);
  border: 1px solid rgba(0, 255, 170, 0.2);
}

.project-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* --------------------------------------------------------------------------
   Contact Page
   -------------------------------------------------------------------------- */
.contact-container {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 40px;
}

.contact-info-cards {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.info-card {
  display: flex;
  align-items: center;
  gap: 16px;
}

.info-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: rgba(0, 255, 170, 0.12);
  color: var(--accent-emerald);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.info-text h4 {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  color: var(--text-muted);
}

.info-text p,
.info-text a {
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 500;
  text-decoration: none;
}

.copy-btn {
  background: none;
  border: none;
  color: var(--accent-emerald);
  cursor: pointer;
  font-size: 0.9rem;
  margin-left: 8px;
  padding: 6px;
  transition: var(--transition);
  min-height: 36px;
  min-width: 36px;
}

.copy-btn:hover {
  transform: scale(1.15);
}

/* Form Styles */
.contact-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  text-align: left;
}

.form-group label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  background: rgba(13, 18, 31, 0.75);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  outline: none;
  transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--accent-emerald);
  box-shadow: 0 0 0 3px rgba(0, 255, 170, 0.2);
}

.form-status {
  padding: 14px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  display: none;
  margin-top: 10px;
}

.form-status.success {
  display: block;
  background: rgba(0, 255, 170, 0.15);
  border: 1px solid var(--accent-emerald);
  color: var(--accent-emerald);
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
footer {
  margin-top: auto;
  padding: 35px 5%;
  background: rgba(7, 9, 14, 0.95);
  border-top: 1px solid var(--glass-border);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.social-links {
  display: flex;
  gap: 16px;
}

.social-links a {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--glass-border);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: var(--transition);
  text-decoration: none;
}

.social-links a:hover {
  background: rgba(0, 255, 170, 0.15);
  border-color: var(--accent-emerald);
  color: var(--accent-emerald);
  transform: translateY(-3px);
}

footer p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* --------------------------------------------------------------------------
   Media Queries & Responsive Viewports (320px to 4K)
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  .hero {
    flex-direction: column-reverse;
    text-align: center;
  }

  .hero-text {
    text-align: center;
  }

  .hero-text p {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-buttons {
    justify-content: center;
  }

  .about-grid,
  .contact-container {
    grid-template-columns: 1fr;
  }

  .about-profile-card {
    position: static;
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: flex;
  }

  nav ul {
    position: fixed;
    top: 70px;
    right: -100%;
    width: 260px;
    height: calc(100vh - 70px);
    background: rgba(7, 9, 14, 0.96);
    backdrop-filter: blur(20px);
    border-left: 1px solid var(--glass-border);
    flex-direction: column;
    padding: 30px 20px;
    align-items: stretch;
    transition: right 0.3s ease;
  }

  nav ul.active {
    right: 0;
  }

  nav ul li a {
    display: block;
    padding: 12px 16px;
    text-align: left;
  }

  nav ul li a.active::after {
    display: none;
  }

  .hero-text h2 {
    font-size: 2.2rem;
  }

  .certificate-gallery {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  }
}

@media (max-width: 480px) {
  .content {
    padding-left: 16px;
    padding-right: 16px;
  }

  .hero-text h2 {
    font-size: 1.8rem;
  }

  .hero-image-wrapper {
    width: 220px;
    height: 220px;
  }

  .btn {
    width: 100%;
  }

  .hero-buttons {
    flex-direction: column;
    width: 100%;
  }
}