/* ============================================================
   PK PORTFOLIO — Design System & Global Styles
   Mobile-first · Accessible · Dark-mode ready tokens
   ============================================================ */

/* — Custom Properties (Light / Dark ready) — */
html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

:root {
  /* Primary */
  --primary:        #125BFB;
  --primary-rgb:    18, 91, 251;
  --primary-light:  #3d7afc;
  --primary-dark:   #0a3fc4;
  --white:          #FFFFFF;

  /* Text */
  --text-primary:   #0F172A;
  --text-secondary: #334155;
  --text-muted:     #64748B;

  /* Backgrounds */
  --bg-body:        #F8FAFC;
  --bg-section:     #F1F5F9;
  --bg-card:        #EEF2FF;
  --bg-accent:      #E6EDFF;
  --bg-white:       #FFFFFF;

  /* Borders */
  --border-light:   #E2E8F0;
  --border-card:    rgba(18, 91, 251, 0.08);

  /* Shadows */
  --shadow-sm:      0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md:      0 4px 12px rgba(0,0,0,0.06), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg:      0 12px 40px rgba(0,0,0,0.08), 0 4px 12px rgba(0,0,0,0.04);
  --shadow-glow:    0 0 40px rgba(var(--primary-rgb), 0.15);
  --shadow-btn:     0 4px 16px rgba(var(--primary-rgb), 0.30);

  /* Radius */
  --radius-sm:  0.5rem;
  --radius-md:  0.75rem;
  --radius-lg:  1rem;
  --radius-xl:  1.5rem;
  --radius-2xl: 2rem;
  --radius-full: 9999px;

  /* Typography */
  --font-display: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing scale */
  --space-xs:  0.25rem;
  --space-sm:  0.5rem;
  --space-md:  1rem;
  --space-lg:  1.5rem;
  --space-xl:  2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  --space-5xl: 8rem;

  /* Sizing */
  --max-width: 1200px;
  --nav-height: 72px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration-fast: 200ms;
  --duration-normal: 350ms;
  --duration-slow: 600ms;
}

/* — Dark-mode tokens — */
[data-theme="dark"] {
  --text-primary:   #E5E7EB;
  --text-secondary: #9CA3AF;
  --text-muted:     #6B7280;
  --bg-body:        #0B0F19;
  --bg-section:     #111827;
  --bg-card:        #1F2937;
  --bg-accent:      #1A2744;
  --bg-white:       #1F2937;
  --border-light:   #374151;
  --border-card:    rgba(18, 91, 251, 0.2);
  --white:          #1F2937;
}

/* Smooth theme transitions */
body,
.navbar,
.navbar.scrolled,
section,
.hero,
.about-card,
.skill-card,
.project-card,
.achievement-card,
.cp-card,
.cert-card,
.contact-form,
.form-input,
.form-textarea,
.footer,
.timeline-card {
  transition: background-color 400ms ease, color 400ms ease, border-color 400ms ease, box-shadow 400ms ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-display);
  color: var(--text-primary);
  background: var(--bg-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul, ol { list-style: none; }

input, textarea {
  font: inherit;
  border: none;
  outline: none;
}

::selection {
  background: rgba(var(--primary-rgb), 0.2);
  color: var(--text-primary);
}

/* — Utility — */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

.section-padding {
  padding: var(--space-4xl) 0;
}

/* ============================================================
   Typography
   ============================================================ */
h1, h2, h3, h4, h5, h6 {
  font-weight: 800;
  line-height: 1.15;
  color: var(--text-primary);
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: rgba(var(--primary-rgb), 0.08);
  border: 1px solid rgba(var(--primary-rgb), 0.15);
  color: var(--primary);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-lg);
}

.section-title {
  font-size: clamp(1.75rem, 5vw, 2.75rem);
  margin-bottom: var(--space-md);
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 540px;
  line-height: 1.7;
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.section-header .section-subtitle {
  margin: 0 auto;
}

/* ============================================================
   Loading Screen
   ============================================================ */
.loading-screen {
  position: fixed;
  inset: 0;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--white);
  transition: opacity 0.6s var(--ease-out), visibility 0.6s;
}

.loading-screen.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.loading-logo {
  font-size: 2rem;
  font-weight: 900;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  margin-bottom: var(--space-xl);
}

.loading-logo span { color: var(--primary); }

.loading-bar-track {
  width: 200px;
  height: 3px;
  background: var(--bg-section);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.loading-bar {
  height: 100%;
  width: 0%;
  background: var(--primary);
  border-radius: var(--radius-full);
  transition: width 0.3s var(--ease-out);
}

/* ============================================================
   Navbar
   ============================================================ */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-height);
  z-index: 1000;
  transition: background var(--duration-normal) var(--ease-out),
              box-shadow var(--duration-normal) var(--ease-out),
              backdrop-filter var(--duration-normal) var(--ease-out);
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  box-shadow: 0 1px 0 var(--border-light), var(--shadow-sm);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1.2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  z-index: 1001;
}

.nav-brand-icon {
  width: 36px; height: 36px;
  background: var(--primary);
  color: var(--white);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  font-size: 1rem;
}

.nav-brand-text span { color: var(--primary); }

.nav-links {
  display: none;
  align-items: center;
  gap: var(--space-xl);
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: color var(--duration-fast);
  position: relative;
}

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

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0;
  width: 0; height: 2px;
  background: var(--primary);
  border-radius: var(--radius-full);
  transition: width var(--duration-normal) var(--ease-out);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-cta {
  padding: 10px 22px;
  background: var(--primary);
  color: var(--white) !important;
  font-weight: 700 !important;
  border-radius: var(--radius-lg);
  transition: box-shadow var(--duration-fast), transform var(--duration-fast) !important;
}

.nav-cta::after { display: none !important; }

.nav-cta:hover {
  box-shadow: var(--shadow-btn);
  transform: translateY(-1px);
}

/* Hamburger */
.nav-hamburger {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  z-index: 1001;
}

.nav-hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--duration-normal) var(--ease-out);
}

.nav-hamburger.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-hamburger.active span:nth-child(2) {
  opacity: 0;
}

.nav-hamburger.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile menu */
.mobile-menu {
  position: fixed;
  inset: 0;
  z-index: 999;
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(20px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-xl);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--duration-normal) var(--ease-out),
              visibility var(--duration-normal);
}

.mobile-menu.active {
  opacity: 1;
  visibility: visible;
}

.mobile-menu a {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  transition: color var(--duration-fast);
}

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

/* Desktop */
@media (min-width: 1024px) {
  .nav-links { display: flex; }
  .nav-hamburger { display: none; }
}

/* ============================================================
   Hero Section
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: calc(var(--nav-height) + var(--space-2xl));
  padding-bottom: var(--space-4xl);
  overflow: hidden;
  background: linear-gradient(135deg, #E6EDFF 0%, #F5F8FF 40%, #FFFFFF 100%);
}

/* Background effects */
.hero-bg {
  position: absolute; inset: 0;
  z-index: 0;
  overflow: hidden;
}

.hero-grid {
  position: absolute; inset: 0;
  background-image: radial-gradient(circle, rgba(var(--primary-rgb), 0.06) 1px, transparent 1px);
  background-size: 32px 32px;
}

.hero-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.12;
  animation: blobFloat 12s ease-in-out infinite alternate;
}

.hero-blob-1 {
  width: 500px; height: 500px;
  background: var(--primary);
  top: -10%; left: -8%;
}

.hero-blob-2 {
  width: 400px; height: 400px;
  background: var(--primary);
  bottom: -10%; right: -5%;
  animation-delay: -4s;
  animation-duration: 15s;
}

.hero-blob-3 {
  width: 250px; height: 250px;
  background: #6366F1;
  top: 30%; right: 20%;
  animation-delay: -8s;
  animation-duration: 18s;
}

@keyframes blobFloat {
  0%   { transform: translate(0, 0) scale(1); }
  100% { transform: translate(30px, -20px) scale(1.1); }
}

.hero .container {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: rgba(var(--primary-rgb), 0.08);
  border: 1px solid rgba(var(--primary-rgb), 0.15);
  color: var(--primary);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  width: fit-content;
}

.hero-badge .pulse {
  position: relative;
  width: 8px; height: 8px;
}

.hero-badge .pulse-ring {
  position: absolute; inset: 0;
  border-radius: 50%;
  background: var(--primary);
  animation: pulse 2s ease-in-out infinite;
}

.hero-badge .pulse-dot {
  position: relative;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--primary);
}

@keyframes pulse {
  0%, 100% { opacity: 0; transform: scale(1); }
  50%      { opacity: 0.6; transform: scale(2.5); }
}

/* Greeting line */
.hero-greeting {
  margin-bottom: var(--space-xs);
}

.hero-greeting-line {
  font-size: clamp(1.25rem, 3vw, 1.6rem);
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: -0.01em;
}

.hero-title {
  font-size: clamp(2.5rem, 7vw, 5rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.03em;
  min-height: 1.1em;
}

.hero-typing-prefix {
  color: var(--text-primary);
}

.hero-typing-text {
  color: var(--text-primary);
}

.hero-typing-text .highlight {
  color: var(--primary);
}

.hero-cursor {
  color: var(--primary);
  font-weight: 300;
  animation: cursorBlink 0.75s step-end infinite;
  margin-left: 2px;
}

@keyframes cursorBlink {
  0%, 100% { opacity: 1; }
  50%      { opacity: 0; }
}

.hero-title .highlight { color: var(--primary); }

.hero-description {
  font-size: clamp(1rem, 2.5vw, 1.15rem);
  color: #334155;
  max-width: 520px;
  line-height: 1.75;
}

.hero-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  padding-top: var(--space-sm);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 14px 28px;
  border-radius: var(--radius-lg);
  font-weight: 700;
  font-size: 0.9rem;
  transition: all var(--duration-normal) var(--ease-out);
}

.btn-primary {
  background: var(--primary);
  color: var(--white);
  box-shadow: var(--shadow-btn);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(var(--primary-rgb), 0.4);
}

.btn-secondary {
  background: var(--bg-white);
  color: var(--text-primary);
  border: 1px solid var(--border-light);
}

.btn-secondary:hover {
  background: var(--bg-section);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-ghost {
  color: var(--primary);
  padding: 14px 16px;
}

.btn-ghost:hover { background: rgba(var(--primary-rgb), 0.06); }

.btn .material-symbols-outlined { font-size: 1.1rem; }

/* Hero image */
.hero-image-wrapper {
  display: flex;
  justify-content: center;
  order: -1;
  margin-bottom: var(--space-lg);
}

.hero-image-container {
  position: relative;
  width: 260px; height: 260px;
}

.hero-image-glow {
  position: absolute; inset: -12px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(18,91,251,0.15), transparent 60%);
  animation: glowPulse 4s ease-in-out infinite;
}

@keyframes glowPulse {
  0%, 100% { opacity: 0.6; transform: scale(1); }
  50%      { opacity: 1; transform: scale(1.08); }
}

.hero-image {
  position: relative;
  width: 100%; height: 100%;
  border-radius: 50%;
  border: 5px solid var(--white);
  box-shadow:
    0 0 0 6px rgba(18,91,251,0.08),
    0 20px 60px rgba(0,0,0,0.1);
  overflow: hidden;
  background: var(--bg-accent);
}

.hero-image img {
  width: 100%; height: 100%;
  object-fit: cover;
}

@media (min-width: 1024px) {
  .hero .container {
    grid-template-columns: 1fr 1fr;
  }

  .hero-image-container {
    width: 400px; height: 400px;
  }

  .hero-image-wrapper {
    justify-content: flex-end;
    align-items: flex-start;
    margin-top: -60px;
    order: 0;
    margin-bottom: 0;
  }
}

/* Hero entry animations */
.hero-content {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}

.hero-content.hero-entered {
  opacity: 1;
  transform: translateY(0);
}

.hero-image-wrapper {
  opacity: 0;
  transform: scale(0.95);
  transition: opacity 0.8s var(--ease-out) 0.15s, transform 0.8s var(--ease-out) 0.15s;
}

.hero-image-wrapper.hero-entered {
  opacity: 1;
  transform: scale(1);
}

/* ============================================================
   About Section
   ============================================================ */
.about { background: var(--bg-section); }

.about .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.about-visual {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

.about-card {
  background: var(--bg-white);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: var(--space-md);
  transition: transform var(--duration-normal) var(--ease-out), box-shadow var(--duration-normal);
}

.about-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.about-card:nth-child(2) { margin-top: var(--space-2xl); }
.about-card:nth-child(3) { margin-top: calc(-1 * var(--space-2xl)); }

.about-card .material-symbols-outlined {
  font-size: 2rem;
  color: var(--primary);
}

.about-card-label {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

.about-text { display: flex; flex-direction: column; gap: var(--space-lg); }

.about-text p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

.about-stats {
  display: flex;
  gap: var(--space-2xl);
  padding-top: var(--space-md);
}

.stat-item { text-align: center; }

.stat-number {
  font-size: 1.75rem;
  font-weight: 900;
  color: var(--primary);
}

.stat-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

@media (min-width: 1024px) {
  .about .container {
    grid-template-columns: 1fr 1fr;
  }
}

/* ============================================================
   Skills Section
   ============================================================ */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: var(--space-md);
}

.skill-card {
  background: var(--bg-white);
  padding: var(--space-xl) var(--space-lg);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-light);
  text-align: center;
  transition: all var(--duration-normal) var(--ease-out);
  cursor: default;
}

.skill-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(var(--primary-rgb), 0.2);
}

.skill-icon-wrap {
  width: 48px; height: 48px;
  margin: 0 auto var(--space-md);
  border-radius: var(--radius-lg);
  background: rgba(var(--primary-rgb), 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--duration-normal) var(--ease-out);
  color: var(--primary);
}

.skill-card:hover .skill-icon-wrap {
  background: var(--primary);
  color: var(--white);
  transform: scale(1.1);
}

.skill-icon-wrap .material-symbols-outlined { font-size: 1.4rem; }

.skill-name {
  font-weight: 700;
  font-size: 0.875rem;
  color: var(--text-primary);
}

/* Skill category tabs */
.skill-tabs {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-2xl);
}

.skill-tab {
  padding: 8px 18px;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  transition: all var(--duration-fast);
  cursor: pointer;
}

.skill-tab:hover,
.skill-tab.active {
  background: var(--primary);
  color: var(--white);
  border-color: var(--primary);
}

/* ============================================================
   Experience Section
   ============================================================ */
.experience { background: var(--bg-section); }

.timeline {
  max-width: 700px;
  margin: 0 auto;
  position: relative;
  padding-left: var(--space-2xl);
}

.timeline::before {
  content: '';
  position: absolute;
  top: 0; bottom: 0; left: 8px;
  width: 2px;
  background: linear-gradient(to bottom, var(--primary), rgba(var(--primary-rgb), 0.15));
  border-radius: var(--radius-full);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--space-2xl);
}

.timeline-dot {
  position: absolute;
  left: calc(-1 * var(--space-2xl) + 1px);
  top: 4px;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--bg-white);
  border: 3px solid var(--primary);
  z-index: 1;
  transition: transform var(--duration-normal) var(--ease-spring);
}

.timeline-item:hover .timeline-dot {
  transform: scale(1.3);
}

.timeline-card {
  background: var(--bg-white);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-light);
  transition: all var(--duration-normal) var(--ease-out);
}

.timeline-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateX(4px);
}

.timeline-header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.timeline-role {
  font-size: 1.1rem;
  font-weight: 800;
}

.timeline-company {
  font-weight: 600;
  color: var(--primary);
  font-size: 0.9rem;
}

.timeline-period {
  padding: 4px 12px;
  background: var(--bg-section);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
}

.timeline-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
}

/* ============================================================
   Projects Section
   ============================================================ */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
}

.project-card {
  background: var(--bg-white);
  border-radius: var(--radius-2xl);
  border: 1px solid var(--border-light);
  overflow: hidden;
  transition: all var(--duration-normal) var(--ease-out);
}

.project-card:hover {
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  transform: translateY(-6px);
}

.project-image {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--bg-accent);
}

.project-image img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform var(--duration-slow) var(--ease-out);
}

.project-card:hover .project-image img {
  transform: scale(1.05);
}

.project-image-overlay {
  position: absolute; inset: 0;
  background: rgba(var(--primary-rgb), 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  opacity: 0;
  transition: opacity var(--duration-normal);
}

.project-card:hover .project-image-overlay {
  opacity: 1;
}

.project-overlay-btn {
  width: 44px; height: 44px;
  background: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  box-shadow: var(--shadow-md);
  transition: transform var(--duration-fast) var(--ease-spring);
}

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

.project-body {
  padding: var(--space-xl);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.project-tag {
  padding: 4px 12px;
  background: rgba(var(--primary-rgb), 0.06);
  color: var(--primary);
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: var(--radius-md);
}

.project-title {
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: var(--space-sm);
}

.project-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: var(--space-lg);
}

.project-actions {
  display: flex;
  gap: var(--space-md);
}

.project-btn {
  padding: 10px 20px;
  border-radius: var(--radius-lg);
  font-size: 0.8rem;
  font-weight: 700;
  transition: all var(--duration-fast);
}

.project-btn-primary {
  background: var(--primary);
  color: var(--white);
}

.project-btn-primary:hover { box-shadow: var(--shadow-btn); }

.project-btn-secondary {
  background: var(--bg-section);
  color: var(--text-primary);
}

.project-btn-secondary:hover { background: var(--bg-accent); }

@media (min-width: 768px) {
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ============================================================
   Achievements Section
   ============================================================ */
.achievements {
  background: var(--primary);
  color: var(--white);
  position: relative;
  overflow: hidden;
}

.achievements-bg-ring {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,0.08);
  pointer-events: none;
}

.achievements-bg-ring:nth-child(1) { width: 600px; height: 600px; }
.achievements-bg-ring:nth-child(2) { width: 800px; height: 800px; }

.achievements-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
  position: relative;
  z-index: 1;
}

.achievement-card {
  text-align: center;
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.1);
  transition: all var(--duration-normal) var(--ease-out);
}

.achievement-card:hover {
  background: rgba(255,255,255,0.12);
  transform: translateY(-4px);
}

.achievement-number {
  font-size: clamp(2rem, 6vw, 3.5rem);
  font-weight: 900;
  line-height: 1;
  margin-bottom: var(--space-sm);
}

.achievement-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  opacity: 0.75;
}

@media (min-width: 768px) {
  .achievements-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ============================================================
   Competitive Programming Section
   ============================================================ */
.cp-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

.cp-card {
  background: var(--bg-white);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  transition: all var(--duration-normal) var(--ease-out);
}

.cp-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(var(--primary-rgb), 0.2);
}

.cp-icon {
  width: 56px; height: 56px;
  min-width: 56px;
  border-radius: var(--radius-lg);
  background: rgba(var(--primary-rgb), 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
}

.cp-info { flex: 1; }

.cp-platform {
  font-weight: 800;
  font-size: 1rem;
  margin-bottom: 2px;
}

.cp-handle {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.cp-stats-row {
  display: flex;
  gap: var(--space-lg);
  margin-top: var(--space-sm);
}

.cp-stat {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.cp-stat strong {
  color: var(--primary);
  font-weight: 800;
}

.cp-link {
  padding: 8px 16px;
  border-radius: var(--radius-md);
  background: rgba(var(--primary-rgb), 0.08);
  color: var(--primary);
  font-size: 0.8rem;
  font-weight: 700;
  transition: all var(--duration-fast);
  white-space: nowrap;
}

.cp-link:hover {
  background: var(--primary);
  color: var(--white);
}

@media (min-width: 768px) {
  .cp-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ============================================================
   Architecture / Systems Section
   ============================================================ */
.architecture { background: var(--bg-section); }

.arch-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

.arch-card {
  background: var(--bg-white);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-light);
  overflow: hidden;
  transition: all var(--duration-normal) var(--ease-out);
  cursor: pointer;
}

.arch-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.arch-image {
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, var(--bg-accent), rgba(var(--primary-rgb), 0.08));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  position: relative;
  overflow: hidden;
}

.arch-image .material-symbols-outlined { font-size: 3rem; opacity: 0.4; }

.arch-image-expand {
  position: absolute;
  top: var(--space-md); right: var(--space-md);
  width: 36px; height: 36px;
  background: rgba(255,255,255,0.9);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--duration-fast);
}

.arch-card:hover .arch-image-expand { opacity: 1; }

.arch-body {
  padding: var(--space-xl);
}

.arch-title {
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: var(--space-sm);
}

.arch-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

@media (min-width: 768px) {
  .arch-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Modal */
.modal-overlay {
  position: fixed; inset: 0;
  z-index: 2000;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
  opacity: 0;
  visibility: hidden;
  transition: all var(--duration-normal) var(--ease-out);
}

.modal-overlay.active { opacity: 1; visibility: visible; }

.modal-content {
  background: var(--bg-white);
  border-radius: var(--radius-2xl);
  max-width: 900px;
  width: 100%;
  max-height: 90vh;
  overflow: auto;
  position: relative;
  transform: scale(0.95) translateY(10px);
  transition: transform var(--duration-normal) var(--ease-out);
}

.modal-overlay.active .modal-content {
  transform: scale(1) translateY(0);
}

.modal-close {
  position: absolute;
  top: var(--space-md); right: var(--space-md);
  width: 40px; height: 40px;
  border-radius: var(--radius-sm);
  background: var(--bg-section);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
  transition: background var(--duration-fast);
}

.modal-close:hover { background: var(--border-light); }

.modal-image {
  width: 100%;
  padding: var(--space-xl);
}

.modal-image img {
  width: 100%;
  border-radius: var(--radius-lg);
}

/* ============================================================
   Contact Section
   ============================================================ */
.contact .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3xl);
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xl);
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.contact-icon {
  width: 48px; height: 48px;
  min-width: 48px;
  border-radius: var(--radius-lg);
  background: rgba(var(--primary-rgb), 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
}

.contact-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

.contact-value {
  font-weight: 700;
  font-size: 1rem;
}

.contact-socials {
  display: flex;
  gap: var(--space-md);
}

.social-link {
  width: 44px; height: 44px;
  border-radius: var(--radius-lg);
  background: var(--bg-section);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--duration-fast);
}

.social-link:hover {
  background: var(--primary);
  color: var(--white);
  transform: translateY(-2px);
}

.social-link svg {
  width: 18px; height: 18px;
  fill: currentColor;
}

/* Contact form */
.contact-form-wrapper {
  background: var(--bg-section);
  padding: var(--space-2xl);
  border-radius: var(--radius-2xl);
  border: 1px solid var(--border-light);
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.form-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-secondary);
  padding-left: 4px;
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 14px 20px;
  border-radius: var(--radius-lg);
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  color: var(--text-primary);
  font-size: 0.9rem;
  transition: all var(--duration-fast);
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.1);
}

.form-textarea {
  resize: none;
  min-height: 140px;
}

.form-submit {
  width: 100%;
  padding: 16px;
  background: var(--primary);
  color: var(--white);
  font-weight: 700;
  font-size: 0.95rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-btn);
  transition: all var(--duration-normal) var(--ease-out);
}

.form-submit:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(var(--primary-rgb), 0.4);
}

@media (min-width: 768px) {
  .form-row { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .contact .container {
    grid-template-columns: 1fr 1fr;
  }
}

/* ============================================================
   Footer
   ============================================================ */
.footer {
  background: var(--bg-white);
  border-top: 1px solid var(--border-light);
  padding: var(--space-2xl) 0;
}

.footer .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
  text-align: center;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-lg);
}

.footer-links a {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  transition: color var(--duration-fast);
}

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

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-muted);
}

@media (min-width: 768px) {
  .footer .container {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }
}

/* ============================================================
   Scroll Reveal Animations
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--duration-slow) var(--ease-out),
              transform var(--duration-slow) var(--ease-out);
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 100ms; }
.reveal-delay-2 { transition-delay: 200ms; }
.reveal-delay-3 { transition-delay: 300ms; }
.reveal-delay-4 { transition-delay: 400ms; }
.reveal-delay-5 { transition-delay: 500ms; }
.reveal-delay-6 { transition-delay: 600ms; }

/* Stagger children */
.stagger-children .reveal {
  transition-delay: calc(var(--stagger-index, 0) * 80ms);
}

/* ============================================================
   Resume Modal
   ============================================================ */
.resume-modal .modal-content {
  max-width: 800px;
  display: flex;
  flex-direction: column;
}

.resume-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-xl);
  border-bottom: 1px solid var(--border-light);
}

.resume-toolbar-title {
  font-weight: 700;
  font-size: 0.9rem;
}

.resume-toolbar-actions {
  display: flex;
  gap: var(--space-sm);
}

.resume-toolbar-btn {
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-section);
  font-size: 0.8rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: background var(--duration-fast);
}

.resume-toolbar-btn:hover { background: var(--border-light); }

.resume-viewer {
  flex: 1;
  min-height: 70vh;
  background: var(--bg-section);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: var(--space-xl);
  text-align: center;
}

/* ============================================================
   Greeting Rotation
   ============================================================ */
.hero-greeting-line {
  display: inline-block;
  transition: opacity 300ms ease, transform 300ms ease;
}

.hero-greeting-line.fade-out {
  opacity: 0;
  transform: translateY(-8px);
}

.hero-greeting-line.fade-in {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   Resume Side Panel
   ============================================================ */
.resume-panel-overlay {
  position: fixed;
  inset: 0;
  z-index: 2000;
  background: rgba(0,0,0,0.4);
  backdrop-filter: blur(4px);
  opacity: 0;
  visibility: hidden;
  transition: opacity 350ms ease, visibility 350ms;
}

.resume-panel-overlay.active {
  opacity: 1;
  visibility: visible;
}

.resume-panel {
  position: fixed;
  top: 0;
  right: 0;
  height: 100%;
  width: 100%;
  max-width: 560px;
  z-index: 2001;
  background: var(--bg-white);
  box-shadow: -8px 0 40px rgba(0,0,0,0.15);
  transform: translateX(100%);
  transition: transform 380ms cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  flex-direction: column;
}

.resume-panel.active {
  transform: translateX(0);
}

.resume-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid var(--border-light);
  flex-shrink: 0;
}

.resume-panel-title {
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--text-primary);
}

.resume-panel-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.resume-panel-btn {
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  background: var(--bg-section);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 4px;
  transition: background var(--duration-fast), color var(--duration-fast);
  text-decoration: none;
}

.resume-panel-btn:hover {
  background: var(--primary);
  color: var(--white);
}

.resume-panel-close {
  width: 36px; height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--duration-fast);
  color: var(--text-primary);
}

.resume-panel-close:hover {
  background: rgba(var(--primary-rgb), 0.08);
}

.resume-panel-body {
  flex: 1;
  overflow: auto;
  background: var(--bg-section);
}

.resume-panel-body iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.resume-panel-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--text-muted);
  gap: var(--space-md);
  padding: var(--space-xl);
  text-align: center;
}

.resume-panel-placeholder .material-symbols-outlined {
  font-size: 3rem;
  opacity: 0.3;
  color: var(--primary);
}

/* Responsive resume panel */
@media (min-width: 768px) {
  .resume-panel {
    max-width: 50vw;
  }
}

@media (max-width: 767px) {
  .resume-panel {
    max-width: 100%;
  }
}

/* Floating Resume Button */
.floating-resume {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 900;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 12px 20px;
  background: var(--primary);
  color: #fff;
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 0.85rem;
  box-shadow: 0 4px 20px rgba(var(--primary-rgb), 0.35);
  transition: transform var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast);
  cursor: pointer;
}

.floating-resume:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 28px rgba(var(--primary-rgb), 0.45);
}

.floating-resume .material-symbols-outlined {
  font-size: 1.1rem;
}

/* ============================================================
   Dark Mode Toggle
   ============================================================ */
.theme-toggle {
  width: 40px; height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--duration-fast), color var(--duration-fast);
  color: var(--text-secondary);
  position: relative;
}

.theme-toggle:hover {
  background: rgba(var(--primary-rgb), 0.08);
  color: var(--primary);
}

.theme-toggle .material-symbols-outlined {
  font-size: 1.25rem;
  transition: transform 400ms var(--ease-spring);
}

.theme-toggle:active .material-symbols-outlined {
  transform: rotate(30deg) scale(0.85);
}

/* ============================================================
   Night Vision Overlay
   ============================================================ */
.night-vision-overlay {
  position: fixed;
  inset: 0;
  z-index: 9998;
  background: rgba(0, 0, 0, 0.85);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 400ms ease, visibility 400ms;
  pointer-events: none;
}

.night-vision-overlay.active {
  opacity: 1;
  visibility: visible;
}

.night-vision-text {
  font-family: var(--font-mono), monospace;
  font-size: clamp(1.2rem, 3vw, 1.8rem);
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  text-shadow: 0 0 20px rgba(var(--primary-rgb), 0.6), 0 0 60px rgba(var(--primary-rgb), 0.3);
  opacity: 0;
  transform: scale(0.9);
  transition: opacity 300ms ease 150ms, transform 300ms var(--ease-spring) 150ms;
}

.night-vision-overlay.active .night-vision-text {
  opacity: 1;
  transform: scale(1);
}

/* ============================================================
   Dark Mode Overrides
   ============================================================ */
[data-theme="dark"] .hero {
  background: linear-gradient(135deg, #0B0F19 0%, #111827 40%, #0B0F19 100%);
}

[data-theme="dark"] .navbar.scrolled {
  background: rgba(11, 15, 25, 0.9);
  box-shadow: 0 1px 0 var(--border-light);
}

[data-theme="dark"] .mobile-menu {
  background: rgba(11, 15, 25, 0.97);
}

[data-theme="dark"] .achievements {
  background: linear-gradient(135deg, #0a2e8a, #0d47d4);
}

[data-theme="dark"] .hero-image {
  border-color: #374151;
}

[data-theme="dark"] .form-input,
[data-theme="dark"] .form-textarea {
  background: var(--bg-card);
  border-color: var(--border-light);
  color: var(--text-primary);
}

[data-theme="dark"] .form-submit {
  background: var(--primary);
  color: #fff;
}

[data-theme="dark"] .loading-screen {
  background: #0B0F19;
}

[data-theme="dark"] .hero-description {
  color: var(--text-secondary);
}

[data-theme="dark"] .hero-greeting-line {
  color: var(--text-muted);
}

[data-theme="dark"] .floating-resume {
  box-shadow: 0 4px 20px rgba(var(--primary-rgb), 0.25);
}

/* ============================================================
   Certifications Section
   ============================================================ */
.certifications-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-xl);
}

.cert-card {
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-lg);
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: transform var(--duration-normal) var(--ease-out),
              box-shadow var(--duration-normal) var(--ease-out),
              border-color var(--duration-normal);
}

.cert-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(var(--primary-rgb), 0.2);
}

.cert-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto var(--space-md);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background: rgba(var(--primary-rgb), 0.08);
  color: var(--primary);
}

.cert-icon .material-symbols-outlined { font-size: 1.6rem; }

.cert-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.cert-issuer {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: var(--space-xs);
}

.cert-date {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
}

.cert-focus {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ============================================================
   Skills Collapse / Expand
   ============================================================ */
.skills-grid.collapsed {
  max-height: 160px;
  overflow: hidden;
  position: relative;
}
@media (min-width: 768px) {
  .skills-grid.collapsed { max-height: 120px; }
}
.skills-grid.collapsed::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 60px;
  background: linear-gradient(transparent, var(--bg-body));
  pointer-events: none;
}
.skills-grid { transition: max-height 350ms var(--ease-out); }

/* ============================================================
   Dark Mode — Skill Card Hover
   ============================================================ */
[data-theme="dark"] .skill-card:hover {
  background: #FFFFFF;
  color: #0F172A;
  border-color: var(--primary);
}
[data-theme="dark"] .skill-card:hover .skill-name { color: #0F172A; }
[data-theme="dark"] .skill-card:hover .skill-icon-wrap {
  background: rgba(var(--primary-rgb), 0.12);
  color: var(--primary);
}

/* ============================================================
   Print / Reduced Motion
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}

@media print {
  .navbar, .loading-screen, .mobile-menu, .floating-resume { display: none; }
  .hero { min-height: auto; padding-top: 0; }
  .section-padding { padding: 1rem 0; }
}