/* ===== Self-hosted Inter Font ===== */
/* cyrillic-ext */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('../assets/fonts/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa2JL7SUc.woff2') format('woff2');
  unicode-range: U+0460-052F, U+1C80-1C8A, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
}
/* cyrillic */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('../assets/fonts/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa0ZL7SUc.woff2') format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
/* greek-ext */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('../assets/fonts/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa2ZL7SUc.woff2') format('woff2');
  unicode-range: U+1F00-1FFF;
}
/* greek */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('../assets/fonts/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa1pL7SUc.woff2') format('woff2');
  unicode-range: U+0370-0377, U+037A-037F, U+0384-038A, U+038C, U+038E-03A1, U+03A3-03FF;
}
/* vietnamese */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('../assets/fonts/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa2pL7SUc.woff2') format('woff2');
  unicode-range: U+0102-0103, U+0110-0111, U+0128-0129, U+0168-0169, U+01A0-01A1, U+01AF-01B0, U+0300-0301, U+0303-0304, U+0308-0309, U+0323, U+0329, U+1EA0-1EF9, U+20AB;
}
/* latin-ext */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('../assets/fonts/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa25L7SUc.woff2') format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('../assets/fonts/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa1ZL7.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

/* ===== CSS Variables ===== */
:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-light: #60a5fa;
  --color-primary-dark: #1d4ed8;
  --color-bg: #ffffff;
  --color-bg-secondary: #f8fafc;
  --color-text: #1e293b;
  --color-text-secondary: #64748b;
  --color-border: #e2e8f0;
  --color-accent: #3b82f6;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Fira Code', 'Courier New', monospace;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;

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

  /* Layout */
  --max-width: 1024px;
  --nav-height: 64px;
  --border-radius: 8px;
  --border-radius-lg: 12px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
}

/* ===== Dark Mode ===== */
[data-theme="dark"] {
  --color-primary: #60a5fa;
  --color-primary-light: #93c5fd;
  --color-primary-dark: #3b82f6;
  --color-bg: #0f172a;
  --color-bg-secondary: #1e293b;
  --color-text: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-border: #334155;
  --color-accent: #60a5fa;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

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

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

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  padding-top: var(--nav-height);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
  overflow-x: hidden;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

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

ul,
ol {
  list-style: none;
}

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

/* Focus styles for keyboard navigation */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

a:focus:not(:focus-visible),
button:focus:not(:focus-visible) {
  outline: none;
}

/* ===== Utility Classes ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  padding-left: max(var(--space-lg), env(safe-area-inset-left, var(--space-lg)));
  padding-right: max(var(--space-lg), env(safe-area-inset-right, var(--space-lg)));
}

.section {
  padding: var(--space-3xl) 0;
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-2xl);
  text-align: center;
  position: relative;
  padding-bottom: var(--space-md);
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light));
  border-radius: 999px;
  transition: width 0.8s cubic-bezier(0.16, 1, 0.3, 1), left 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.section-title.animate-in::after {
  width: 60px;
  left: calc(50% - 30px);
}

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--nav-height);
  background-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  transition: box-shadow var(--transition-base), background-color var(--transition-base);
  padding: 0 env(safe-area-inset-right) 0 env(safe-area-inset-left);
}

[data-theme="dark"] .navbar {
  background-color: rgba(15, 23, 42, 0.85);
}

.navbar.scrolled {
  box-shadow: var(--shadow-md);
}

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

.nav-logo {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-primary);
}

.nav-logo:hover {
  color: var(--color-primary-dark);
}

.nav-menu {
  display: flex;
  gap: var(--space-lg);
}

.nav-link {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: width var(--transition-base);
}

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

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

/* Hamburger Button */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  padding: 10px;
}

.hamburger,
.hamburger::before,
.hamburger::after {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: all var(--transition-base);
}

.hamburger {
  position: relative;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  left: 0;
}

.hamburger::before {
  top: -7px;
}

.hamburger::after {
  top: 7px;
}

/* Hamburger → X animation */
.nav-toggle.active .hamburger {
  background-color: transparent;
}

.nav-toggle.active .hamburger::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle.active .hamburger::after {
  top: 0;
  transform: rotate(-45deg);
}

/* ===== Hero Section ===== */
.hero {
  min-height: calc(100vh - var(--nav-height));
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
  padding: var(--space-3xl) 0;
}

.hero-container {
  display: flex;
  align-items: center;
  gap: var(--space-3xl);
}

.hero-avatar {
  flex-shrink: 0;
}

.hero-avatar-img {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--color-primary-light);
  box-shadow: var(--shadow-lg);
  /* Placeholder background when image is missing */
  background-color: var(--color-bg-secondary);
}

.hero-content {
  flex: 1;
}

.hero-name {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  line-height: 1.2;
}

.hero-tagline {
  font-size: var(--font-size-xl);
  color: var(--color-primary);
  font-weight: 500;
  margin-bottom: var(--space-lg);
}

.hero-bio {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-xl);
  max-width: 560px;
}

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.75rem;
  font-size: var(--font-size-base);
  font-weight: 600;
  border-radius: var(--border-radius);
  transition: all var(--transition-base);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  transition: width 0.6s ease, height 0.6s ease;
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #ffffff;
  border: 2px solid var(--color-primary);
}

.btn-primary:hover {
  background-color: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(37, 99, 235, 0.35);
}

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(37, 99, 235, 0.25);
}

/* ===== Timeline ===== */
.timeline {
  position: relative;
  max-width: 720px;
  margin: 0 auto;
  padding-left: 40px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 15px;
  top: 0;
  bottom: 0;
  width: 2px;
  background-color: var(--color-border);
}

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

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-dot {
  position: absolute;
  left: -33px;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background-color: var(--color-primary);
  border: 3px solid var(--color-bg);
  box-shadow: 0 0 0 2px var(--color-primary);
  z-index: 1;
}

.timeline-content {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-lg);
  padding: var(--space-lg) var(--space-xl);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.timeline-content:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

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

.timeline-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text);
}

.timeline-date {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.timeline-subtitle {
  font-size: var(--font-size-base);
  color: var(--color-primary);
  font-weight: 500;
  margin-bottom: var(--space-sm);
}

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

.timeline-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.timeline-list li {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  padding-left: var(--space-lg);
  position: relative;
  margin-bottom: var(--space-xs);
}

.timeline-list li:last-child {
  margin-bottom: 0;
}

.timeline-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-accent);
}

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

.project-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base), border-color var(--transition-base);
  display: flex;
  flex-direction: column;
}

.project-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-5px);
  border-color: var(--color-primary-light);
}

.project-card-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.project-name {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text);
}

.project-date {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  white-space: nowrap;
}

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

.project-highlights {
  list-style: disc;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-md);
}

.project-highlights li {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-xs);
}

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

.tag {
  display: inline-block;
  padding: 0.2rem 0.65rem;
  font-size: var(--font-size-xs);
  font-weight: 500;
  color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.08);
  border-radius: 999px;
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.tag:hover {
  background-color: rgba(37, 99, 235, 0.18);
  transform: translateY(-1px);
}

.project-links {
  display: flex;
  gap: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

.project-link:hover {
  color: var(--color-primary);
}

.project-link svg {
  flex-shrink: 0;
}

/* ===== Skills ===== */
.skills-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2xl);
  max-width: 800px;
  margin: 0 auto;
}

.skill-category {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.skill-category:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.skill-category-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}

.skill-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.skill-item {
  width: 100%;
}

.skill-info {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: var(--space-xs);
}

.skill-name {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text);
}

.skill-percent {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-primary);
}

.skill-bar {
  width: 100%;
  height: 8px;
  background-color: var(--color-bg-secondary);
  border-radius: 999px;
  overflow: hidden;
}

.skill-fill {
  height: 100%;
  width: var(--skill-width);
  background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light));
  border-radius: 999px;
  transition: width 1s ease-out;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.skill-tag {
  display: inline-block;
  padding: 0.35rem 0.85rem;
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  transition: all var(--transition-fast);
}

.skill-tag:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.06);
}

/* ===== Certificates & Honors ===== */
.certs-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

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

.cert-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.cert-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background-color: rgba(37, 99, 235, 0.08);
  color: var(--color-primary);
  margin-bottom: var(--space-md);
}

.cert-name {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
}

.cert-org {
  font-size: var(--font-size-sm);
  color: var(--color-primary);
  font-weight: 500;
  margin-bottom: var(--space-xs);
}

.cert-date {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.cert-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ===== Contact ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
  max-width: 960px;
  margin: 0 auto;
}

.contact-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.contact-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.contact-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: rgba(37, 99, 235, 0.08);
  color: var(--color-primary);
  flex-shrink: 0;
}

.contact-info {
  min-width: 0;
}

.contact-label {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-xs);
}

.contact-value {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text);
  overflow-wrap: break-word;
}

.contact-value--text {
  color: var(--color-text);
}

/* ===== Language Toggle ===== */
.lang-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 44px;
  padding: 0 var(--space-sm);
  border-radius: var(--border-radius);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.lang-toggle:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.08);
}

/* ===== Theme Toggle ===== */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.theme-toggle:hover {
  color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.08);
}

.theme-icon--moon {
  display: none;
}

[data-theme="dark"] .theme-icon--sun {
  display: none;
}

[data-theme="dark"] .theme-icon--moon {
  display: block;
}

[data-theme="dark"] .tag {
  background-color: rgba(96, 165, 250, 0.12);
}

[data-theme="dark"] .cert-icon,
[data-theme="dark"] .contact-icon {
  background-color: rgba(96, 165, 250, 0.12);
}

[data-theme="dark"] .skill-tag:hover {
  background-color: rgba(96, 165, 250, 0.1);
}

[data-theme="dark"] .timeline-list li::before {
  background-color: var(--color-accent);
}

/* ===== Hero Entrance Animations ===== */
@keyframes hero-fade-up {
  from {
    opacity: 0;
    transform: translateY(40px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes hero-scale-in {
  from {
    opacity: 0;
    transform: scale(0.6);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes hero-fade-left {
  from {
    opacity: 0;
    transform: translateX(-50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.hero-avatar-img {
  animation: hero-scale-in 0.8s cubic-bezier(0.34, 1.56, 0.64, 1) both;
  /* floating effect */
}

.hero-avatar-img.animate-in {
  animation: hero-scale-in 0.8s cubic-bezier(0.34, 1.56, 0.64, 1) both, float 4s ease-in-out 1.2s infinite;
}

.hero-name {
  opacity: 0;
  animation: hero-fade-up 0.7s ease-out 0.2s both;
}

.hero-tagline {
  opacity: 0;
  animation: hero-fade-up 0.7s ease-out 0.4s both;
}

.hero-bio {
  opacity: 0;
  animation: hero-fade-up 0.7s ease-out 0.55s both;
}

.hero-actions {
  opacity: 0;
  animation: hero-fade-up 0.7s ease-out 0.7s both;
}

/* ===== Scroll Animations ===== */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(50px);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
  will-change: opacity, transform;
}

.animate-on-scroll.animate-in {
  opacity: 1;
  transform: translateY(0);
}

/* Animation variants */
.animate-on-scroll.slide-left {
  transform: translateX(-60px);
}

.animate-on-scroll.slide-left.animate-in {
  transform: translateX(0);
}

.animate-on-scroll.slide-right {
  transform: translateX(60px);
}

.animate-on-scroll.slide-right.animate-in {
  transform: translateX(0);
}

.animate-on-scroll.scale-up {
  transform: scale(0.85) translateY(30px);
}

.animate-on-scroll.scale-up.animate-in {
  transform: scale(1) translateY(0);
}

/* Stagger delay for project cards */
.projects-grid .project-card:nth-child(1) { transition-delay: 0s; }
.projects-grid .project-card:nth-child(2) { transition-delay: 0.12s; }
.projects-grid .project-card:nth-child(3) { transition-delay: 0.24s; }
.projects-grid .project-card:nth-child(4) { transition-delay: 0.36s; }

/* Stagger delay for contact cards */
.contact-grid .contact-card:nth-child(1) { transition-delay: 0s; }
.contact-grid .contact-card:nth-child(2) { transition-delay: 0.12s; }
.contact-grid .contact-card:nth-child(3) { transition-delay: 0.24s; }

/* Stagger delay for children */
.animate-on-scroll.animate-in .stagger-1 { transition-delay: 0.1s; }
.animate-on-scroll.animate-in .stagger-2 { transition-delay: 0.2s; }
.animate-on-scroll.animate-in .stagger-3 { transition-delay: 0.3s; }
.animate-on-scroll.animate-in .stagger-4 { transition-delay: 0.4s; }
.animate-on-scroll.animate-in .stagger-5 { transition-delay: 0.5s; }
.animate-on-scroll.animate-in .stagger-6 { transition-delay: 0.6s; }

/* ===== Skill Bar Animation ===== */
@keyframes skill-fill-in {
  from { width: 0; }
}

.skill-fill {
  width: 0;
  transition: none;
}

.skill-fill.animate-in {
  width: var(--skill-width);
  animation: skill-fill-in 1.2s cubic-bezier(0.16, 1, 0.3, 1) both;
}

/* Stagger skill bars */
.skill-item:nth-child(1) .skill-fill.animate-in { animation-delay: 0.1s; }
.skill-item:nth-child(2) .skill-fill.animate-in { animation-delay: 0.2s; }
.skill-item:nth-child(3) .skill-fill.animate-in { animation-delay: 0.3s; }
.skill-item:nth-child(4) .skill-fill.animate-in { animation-delay: 0.4s; }
.skill-item:nth-child(5) .skill-fill.animate-in { animation-delay: 0.5s; }
.skill-item:nth-child(6) .skill-fill.animate-in { animation-delay: 0.6s; }

/* ===== Blog ===== */
.blog-hero {
  padding: var(--space-3xl) 0 var(--space-xl);
  background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
  text-align: center;
}

.blog-hero-title {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
}

.blog-hero-desc {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
}

.blog-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
  display: flex;
  flex-direction: column;
}

.blog-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.blog-card-img {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 180px;
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-border) 100%);
  color: var(--color-primary);
}

.blog-card-body {
  padding: var(--space-xl);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.blog-card-meta {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.blog-card-tag {
  display: inline-block;
  padding: 0.15rem 0.55rem;
  font-size: var(--font-size-xs);
  font-weight: 500;
  color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.08);
  border-radius: 999px;
}

.blog-card-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  line-height: 1.4;
}

.blog-card-title a {
  color: var(--color-text);
  transition: color var(--transition-fast);
}

.blog-card-title a:hover {
  color: var(--color-primary);
}

.blog-card-excerpt {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-lg);
  flex: 1;
}

.blog-card-link {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-primary);
  margin-top: auto;
}

.blog-card-link:hover {
  color: var(--color-primary-dark);
}

/* ===== Blog Post ===== */
.post {
  padding: var(--space-3xl) 0;
}

.post-header {
  max-width: 720px;
  margin: 0 auto var(--space-2xl);
}

.post-back {
  display: inline-block;
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
  transition: color var(--transition-fast);
}

.post-back:hover {
  color: var(--color-primary);
}

.post-title {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.3;
  margin-bottom: var(--space-md);
}

.post-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  flex-wrap: wrap;
}

.post-meta-sep {
  color: var(--color-border);
}

.post-tag {
  display: inline-block;
  padding: 0.15rem 0.55rem;
  font-size: var(--font-size-xs);
  font-weight: 500;
  color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.08);
  border-radius: 999px;
}

.post-content {
  max-width: 720px;
  margin: 0 auto;
}

.post-content h2 {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-text);
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.post-content h3 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-sm);
}

.post-content p {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

.post-content ul,
.post-content ol {
  list-style: disc;
  padding-left: var(--space-xl);
  margin-bottom: var(--space-lg);
}

.post-content ol {
  list-style: decimal;
}

.post-content li {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-xs);
}

.post-content strong {
  color: var(--color-text);
  font-weight: 600;
}

.post-content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background-color: var(--color-bg-secondary);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  color: var(--color-primary);
}

.post-content pre {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-lg);
  overflow-x: auto;
  margin-bottom: var(--space-lg);
}

.post-content pre code {
  background: none;
  padding: 0;
  font-size: var(--font-size-sm);
  color: var(--color-text);
}

[data-theme="dark"] .blog-card-img {
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, rgba(51, 65, 85, 0.5) 100%);
}

[data-theme="dark"] .blog-card-tag,
[data-theme="dark"] .post-tag {
  background-color: rgba(96, 165, 250, 0.12);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
  }

  .section {
    padding: var(--space-2xl) 0;
  }

  .section-title {
    font-size: var(--font-size-2xl);
  }

  /* Mobile Nav */
  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    flex-direction: column;
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-lg);
    gap: var(--space-md);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-md);
  }

  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-link {
    font-size: var(--font-size-base);
    padding: var(--space-sm) 0;
  }

  .nav-link::after {
    bottom: 0;
  }

  /* Mobile Hero */
  .hero {
    padding: var(--space-2xl) 0;
  }

  .hero-container {
    flex-direction: column;
    text-align: center;
    gap: var(--space-xl);
  }

  .hero-avatar-img {
    width: 150px;
    height: 150px;
  }

  .hero-name {
    font-size: var(--font-size-3xl);
  }

  .hero-tagline {
    font-size: var(--font-size-lg);
  }

  .hero-bio {
    font-size: var(--font-size-base);
  }

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

  /* Mobile Timeline */
  .timeline {
    padding-left: 30px;
  }

  .timeline::before {
    left: 10px;
  }

  .timeline-dot {
    left: -28px;
  }

  .timeline-header {
    flex-direction: column;
    gap: var(--space-xs);
  }

  .timeline-content {
    padding: var(--space-md) var(--space-lg);
  }

  /* Mobile Projects */
  .projects-grid {
    grid-template-columns: 1fr;
  }

  .project-card-header {
    flex-direction: column;
    gap: var(--space-xs);
  }

  .project-card {
    padding: var(--space-lg);
  }

  /* Mobile Skills */
  .skills-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .skill-category {
    padding: var(--space-lg);
  }

  /* Mobile Certificates */
  .certs-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .cert-card {
    padding: var(--space-lg);
  }

  /* Mobile Contact */
  .contact-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .contact-card {
    padding: var(--space-lg);
  }

  /* Mobile Blog */
  .blog-hero-title {
    font-size: var(--font-size-3xl);
  }

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

  .blog-card-img {
    height: 140px;
  }

  .blog-card-body {
    padding: var(--space-lg);
  }

  .post-title {
    font-size: var(--font-size-3xl);
  }

  .post-content h2 {
    font-size: var(--font-size-xl);
  }

  .post-content h3 {
    font-size: var(--font-size-lg);
  }
}

/* ===== Tablet (769px - 1024px) ===== */
@media (min-width: 769px) and (max-width: 1024px) {
  .container {
    padding: 0 var(--space-xl);
  }

  .hero-avatar-img {
    width: 170px;
    height: 170px;
  }

  .hero-name {
    font-size: var(--font-size-3xl);
  }

  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
  }

  .certs-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .contact-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .skills-grid {
    gap: var(--space-xl);
  }
}

/* ===== Small Phones (max 480px) ===== */
@media (max-width: 480px) {
  :root {
    --nav-height: 52px;
  }

  .container {
    padding: 0 var(--space-md);
  }

  .nav-container {
    gap: var(--space-sm);
  }

  .nav-logo {
    font-size: var(--font-size-lg);
  }

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

  .hero-avatar-img {
    width: 120px;
    height: 120px;
  }

  .hero-name {
    font-size: var(--font-size-2xl);
  }

  .hero-tagline {
    font-size: var(--font-size-base);
  }

  .hero-bio {
    font-size: var(--font-size-sm);
  }

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

  .hero-actions .btn {
    width: 100%;
    text-align: center;
  }

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

  .section-title {
    font-size: var(--font-size-xl);
  }

  .timeline {
    padding-left: 24px;
  }

  .timeline::before {
    left: 8px;
  }

  .timeline-dot {
    left: -22px;
    width: 10px;
    height: 10px;
  }

  .timeline-content {
    padding: var(--space-md);
  }

  .timeline-title {
    font-size: var(--font-size-base);
  }

  .project-card {
    padding: var(--space-md);
  }

  .project-name {
    font-size: var(--font-size-lg);
  }

  .cert-card {
    padding: var(--space-md);
  }

  .contact-card {
    padding: var(--space-md);
    flex-direction: column;
    text-align: center;
    gap: var(--space-sm);
  }

  .skill-tag {
    font-size: var(--font-size-xs);
    padding: 0.25rem 0.65rem;
  }

  .blog-hero-title {
    font-size: var(--font-size-2xl);
  }

  .blog-card-body {
    padding: var(--space-md);
  }

  .post-title {
    font-size: var(--font-size-2xl);
  }

  .post-content pre {
    padding: var(--space-md);
    font-size: var(--font-size-xs);
  }
}

/* ===== Print Styles ===== */
@media print {
  *,
  *::before,
  *::after {
    background: transparent !important;
    color: #000 !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  body {
    padding-top: 0;
    font-size: 12pt;
    line-height: 1.5;
  }

  .navbar,
  .theme-toggle,
  .lang-toggle,
  .nav-toggle,
  .hero-actions,
  .project-links,
  .blog-card-link,
  .post-back {
    display: none !important;
  }

  .section {
    padding: 1rem 0;
    page-break-inside: avoid;
  }

  .hero {
    min-height: auto;
    padding: 1rem 0;
  }

  .hero-container {
    flex-direction: row;
    gap: 2rem;
  }

  .hero-avatar-img {
    width: 100px;
    height: 100px;
  }

  .container {
    max-width: 100%;
    padding: 0;
  }

  .animate-on-scroll {
    opacity: 1 !important;
    transform: none !important;
  }

  a {
    text-decoration: underline;
  }

  a[href^="http"]::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #555 !important;
  }

  a[href^="#"]::after,
  a[href^="index.html"]::after,
  a[href^="blog"]::after {
    content: "";
  }

  .timeline-content,
  .project-card,
  .cert-card,
  .contact-card,
  .skill-category {
    page-break-inside: avoid;
    border: 1px solid #ccc;
  }

  h2, h3 {
    page-break-after: avoid;
  }
}