/* ============================================
   RESET
   ============================================ */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body { line-height: 1.6; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
img, picture, video, canvas, svg { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; }
p, h1, h2, h3, h4, h5, h6 { overflow-wrap: break-word; }
ul, ol { list-style: none; }
a { text-decoration: none; color: inherit; }
button { background: none; border: none; cursor: pointer; }

/* ============================================
   CSS CUSTOM PROPERTIES
   ============================================ */
:root {
  --color-primary: #0ea5e9;
  --color-primary-hover: #0284c7;
  --color-primary-light: #e0f2fe;
  --color-primary-dark: #0369a1;

  --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;

  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --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: 2rem;
  --font-size-4xl: 2.5rem;
  --font-size-5xl: 3rem;

  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;

  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 50%;

  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;

  --container-max: 1140px;
  --header-height: 72px;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: #1e293b;
  --bg-card-hover: #334155;
  --bg-header: rgba(15, 23, 42, 0.85);
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-tertiary: #64748b;
  --border-color: #334155;
  --border-color-light: #1e293b;
  --tag-bg: #1e293b;
  --tag-text: #0ea5e9;
  --tag-border: #334155;
  --btn-outline-border: #475569;
  --btn-outline-text: #f1f5f9;
  --btn-outline-hover-bg: #1e293b;
  --shadow-card: 0 4px 6px -1px rgba(0,0,0,0.3);
  --timeline-line: #334155;
  --timeline-dot: #0ea5e9;
  --lightbox-bg: rgba(0, 0, 0, 0.92);
}

/* Light Theme */
[data-theme="light"] {
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --bg-header: rgba(255, 255, 255, 0.85);
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #94a3b8;
  --border-color: #e2e8f0;
  --border-color-light: #f1f5f9;
  --tag-bg: #f0f9ff;
  --tag-text: #0369a1;
  --tag-border: #bae6fd;
  --btn-outline-border: #cbd5e1;
  --btn-outline-text: #0f172a;
  --btn-outline-hover-bg: #f1f5f9;
  --shadow-card: 0 4px 6px -1px rgba(0,0,0,0.08);
  --timeline-line: #e2e8f0;
  --timeline-dot: #0ea5e9;
  --lightbox-bg: rgba(0, 0, 0, 0.88);
}

/* ============================================
   BASE STYLES
   ============================================ */
body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color var(--transition-base), color var(--transition-base);
}

::selection {
  background-color: var(--color-primary);
  color: #ffffff;
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ============================================
   LAYOUT
   ============================================ */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.section {
  padding: var(--space-4xl) 0;
  background-color: var(--bg-primary);
  transition: background-color var(--transition-base);
}

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

.section__title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-bold);
  color: var(--text-primary);
  text-align: center;
  margin-bottom: var(--space-3xl);
}

/* ============================================
   COMPONENTS: BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.75rem 1.5rem;
  font-size: var(--font-size-base);
  font-weight: var(--font-semibold);
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  cursor: pointer;
  border: 2px solid transparent;
  line-height: 1.4;
}

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

.btn--primary:hover {
  background-color: var(--color-primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(14, 165, 233, 0.4);
}

.btn--outline {
  background: transparent;
  color: var(--btn-outline-text);
  border-color: var(--btn-outline-border);
}

.btn--outline:hover {
  background-color: var(--btn-outline-hover-bg);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn--lg {
  padding: 1rem 2rem;
  font-size: var(--font-size-lg);
}

.btn .icon {
  display: inline-block;
  flex-shrink: 0;
}

/* ============================================
   COMPONENTS: TAGS
   ============================================ */
.tag {
  display: inline-block;
  padding: 0.3rem 0.75rem;
  font-size: var(--font-size-sm);
  font-weight: var(--font-medium);
  color: var(--tag-text);
  background-color: var(--tag-bg);
  border: 1px solid var(--tag-border);
  border-radius: var(--radius-md);
  white-space: nowrap;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.tag--sm {
  padding: 0.15rem 0.5rem;
  font-size: var(--font-size-xs);
}

.tag--skill {
  padding: 0.35rem 0.85rem;
}

/* ============================================
   HEADER & NAVIGATION
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background-color: var(--bg-header);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: box-shadow var(--transition-base), background-color var(--transition-base), border-color var(--transition-base);
  height: var(--header-height);
}

.header--scrolled {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.nav__logo {
  font-size: var(--font-size-xl);
  font-weight: var(--font-bold);
  color: var(--color-primary);
  letter-spacing: -0.5px;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.nav__link {
  display: block;
  padding: 0.5rem 0.75rem;
  font-size: var(--font-size-sm);
  font-weight: var(--font-medium);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

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

.nav__link.active {
  color: var(--color-primary);
  background-color: var(--tag-bg);
}

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

/* Language Toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  font-size: var(--font-size-sm);
  font-weight: var(--font-bold);
  border: 1px solid var(--border-color);
}

.lang-toggle:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: var(--tag-bg);
}

/* Theme Toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  color: var(--color-primary);
  background-color: var(--tag-bg);
}

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

/* Hamburger */
.nav__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
}

.nav__hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-base);
  transform-origin: center;
}

.nav__hamburger[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav__hamburger[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav__hamburger[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ============================================
   HERO
   ============================================ */
.hero {
  padding-top: calc(var(--header-height) + var(--space-4xl));
  padding-bottom: var(--space-4xl);
  background-color: var(--bg-primary);
  transition: background-color var(--transition-base);
  min-height: 100vh;
  display: flex;
  align-items: center;
}

.hero__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3xl);
}

.hero__content {
  flex: 1;
  max-width: 600px;
}

.hero__greeting {
  font-size: var(--font-size-lg);
  color: var(--color-primary);
  font-weight: var(--font-medium);
  margin-bottom: var(--space-sm);
}

.hero__name {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-bold);
  color: var(--text-primary);
  line-height: 1.1;
  margin-bottom: var(--space-md);
}

.hero__title {
  font-size: var(--font-size-2xl);
  color: var(--text-secondary);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-md);
}

.hero__subtitle {
  font-size: var(--font-size-lg);
  color: var(--text-tertiary);
  line-height: 1.6;
  margin-bottom: var(--space-xl);
}

.hero__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.hero__image {
  flex-shrink: 0;
}

.hero__image img {
  width: 280px;
  height: 280px;
  border-radius: var(--radius-full);
  object-fit: cover;
  border: 4px solid var(--color-primary);
  box-shadow: 0 0 0 8px var(--tag-bg);
}

/* ============================================
   ABOUT
   ============================================ */
.about__content {
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
}

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

.about__content p:last-child {
  margin-bottom: 0;
}

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

.skills__category {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: border-color var(--transition-base), background-color var(--transition-base);
}

.skills__category:hover {
  border-color: var(--color-primary);
}

.skills__category-title {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-lg);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
}

.skills__category-title .icon {
  color: var(--color-primary);
  flex-shrink: 0;
}

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

/* ============================================
   EXPERIENCE (Timeline)
   ============================================ */
.timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  padding-left: var(--space-2xl);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 0;
  bottom: 0;
  width: 2px;
  background-color: var(--timeline-line);
}

.timeline__item {
  position: relative;
  margin-bottom: var(--space-3xl);
}

.timeline__item:last-child {
  margin-bottom: 0;
}

.timeline__marker {
  position: absolute;
  left: calc(-1 * var(--space-2xl) + 0px);
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: var(--radius-full);
  background-color: var(--timeline-dot);
  border: 3px solid var(--bg-primary);
  box-shadow: 0 0 0 2px var(--timeline-dot);
  z-index: 1;
}

.timeline__content {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: border-color var(--transition-base), background-color var(--transition-base);
}

.timeline__header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-md);
  margin-bottom: var(--space-xs);
}

.timeline__company {
  font-size: var(--font-size-xl);
  font-weight: var(--font-bold);
  color: var(--text-primary);
}

.timeline__period {
  font-size: var(--font-size-sm);
  color: var(--text-tertiary);
  white-space: nowrap;
  padding: 0.2rem 0.6rem;
  background-color: var(--tag-bg);
  border-radius: var(--radius-sm);
  border: 1px solid var(--tag-border);
}

.timeline__role {
  font-size: var(--font-size-base);
  color: var(--color-primary);
  font-weight: var(--font-medium);
  margin-bottom: var(--space-xl);
}

.timeline__project {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid var(--border-color);
}

.timeline__project:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.timeline__project h4 {
  font-size: var(--font-size-base);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.timeline__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: var(--space-md);
}

.timeline__details {
  list-style: none;
  padding: 0;
}

.timeline__details li {
  position: relative;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-sm);
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
  line-height: 1.6;
}

.timeline__details li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background-color: var(--color-primary);
}

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

/* ============================================
   PROJECTS (Cards + Filter)
   ============================================ */
.projects__filters {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-2xl);
}

.filter-btn {
  padding: 0.5rem 1.25rem;
  font-size: var(--font-size-sm);
  font-weight: var(--font-medium);
  color: var(--text-secondary);
  background-color: transparent;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  cursor: pointer;
}

.filter-btn:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.filter-btn.active {
  background-color: var(--color-primary);
  color: #ffffff;
  border-color: var(--color-primary);
}

.projects__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

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

.project-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: var(--color-primary);
}

.project-card.hidden {
  display: none;
}

.project-card__header {
  margin-bottom: var(--space-lg);
}

.project-card__header .icon {
  color: var(--color-primary);
}

.project-card__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

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

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: auto;
}

/* ============================================
   EDUCATION
   ============================================ */
.education__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
  max-width: 900px;
  margin: 0 auto;
}

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

.education__item:hover {
  border-color: var(--color-primary);
}

.education__icon {
  display: flex;
  justify-content: center;
  margin-bottom: var(--space-lg);
  color: var(--color-primary);
}

.education__degree {
  font-size: var(--font-size-lg);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.education__school {
  font-size: var(--font-size-base);
  color: var(--color-primary);
  font-weight: var(--font-medium);
  margin-bottom: var(--space-xs);
}

.education__period {
  font-size: var(--font-size-sm);
  color: var(--text-tertiary);
  margin-bottom: var(--space-md);
}

.education__detail {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ============================================
   CERTIFICATIONS
   ============================================ */
.certs__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
  max-width: 900px;
  margin: 0 auto;
}

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

.cert__item:hover {
  border-color: var(--color-primary);
}

.cert__icon {
  display: flex;
  justify-content: center;
  margin-bottom: var(--space-md);
  color: var(--color-primary);
}

.cert__name {
  font-size: var(--font-size-base);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

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

.cert__date {
  font-size: var(--font-size-sm);
  color: var(--text-tertiary);
}

/* ============================================
   GALLERY
   ============================================ */
.gallery__intro {
  text-align: center;
  color: var(--text-secondary);
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-2xl);
  margin-top: calc(-1 * var(--space-xl));
}

.gallery__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  max-width: 800px;
  margin: 0 auto;
}

.gallery__item {
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  position: relative;
  aspect-ratio: 3 / 2;
}

.gallery__item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.gallery__item:hover img {
  transform: scale(1.05);
}

.gallery__item::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0);
  transition: background var(--transition-base);
  pointer-events: none;
}

.gallery__item:hover::after {
  background: rgba(0,0,0,0.08);
}

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--lightbox-bg);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
  padding: var(--space-xl);
}

.lightbox.active {
  opacity: 1;
  visibility: visible;
}

.lightbox__close {
  position: absolute;
  top: var(--space-xl);
  right: var(--space-xl);
  color: #ffffff;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
  transition: background-color var(--transition-fast);
  z-index: 1001;
}

.lightbox__close:hover {
  background-color: rgba(255, 255, 255, 0.15);
}

.lightbox__img {
  max-width: 90vw;
  max-height: 85vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  transform: scale(0.95);
  transition: transform var(--transition-base);
}

.lightbox.active .lightbox__img {
  transform: scale(1);
}

/* ============================================
   CONTACT
   ============================================ */
.contact__container {
  text-align: center;
}

.contact__intro {
  max-width: 560px;
  margin: 0 auto var(--space-2xl);
  color: var(--text-secondary);
  font-size: var(--font-size-lg);
  margin-top: calc(-1 * var(--space-xl));
}

.contact__links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-2xl);
}

.contact__item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.75rem 1.25rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  transition: all var(--transition-base);
  font-size: var(--font-size-sm);
}

.contact__item:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: var(--tag-bg);
  transform: translateY(-2px);
}

.contact__item .icon {
  flex-shrink: 0;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  padding: var(--space-xl) 0;
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  transition: background-color var(--transition-base), border-color var(--transition-base);
}

.footer__container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer__copyright,
.footer__updated {
  font-size: var(--font-size-sm);
  color: var(--text-tertiary);
}

/* ============================================
   BACK-TO-TOP
   ============================================ */
.back-to-top {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background-color: var(--color-primary);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all var(--transition-base);
  box-shadow: 0 4px 12px rgba(14, 165, 233, 0.4);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background-color: var(--color-primary-hover);
  transform: translateY(-2px);
}

/* ============================================
   ANIMATIONS
   ============================================ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ============================================
   MEDIA QUERIES: TABLET (<=1024px)
   ============================================ */
@media (max-width: 1024px) {
  .container {
    padding: 0 var(--space-lg);
  }

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

  .hero__name {
    font-size: var(--font-size-4xl);
  }

  .hero__image img {
    width: 240px;
    height: 240px;
  }

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

  .certs__grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ============================================
   MEDIA QUERIES: MOBILE (<=768px)
   ============================================ */
@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }

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

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

  .section__title {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--space-2xl);
  }

  /* Nav Mobile */
  .nav__hamburger {
    display: flex;
  }

  .nav__list {
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--bg-header);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    padding: var(--space-md);
    gap: 0;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: 99;
  }

  .nav__list.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav__link {
    padding: 0.75rem var(--space-md);
    width: 100%;
  }

  /* Hero Mobile */
  .hero {
    padding-top: calc(var(--header-height) + var(--space-2xl));
    padding-bottom: var(--space-2xl);
    min-height: auto;
  }

  .hero__container {
    flex-direction: column-reverse;
    text-align: center;
  }

  .hero__content {
    max-width: 100%;
  }

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

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

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

  .hero__tags {
    justify-content: center;
  }

  .hero__actions {
    justify-content: center;
  }

  .hero__image img {
    width: 200px;
    height: 200px;
  }

  /* Skills Mobile */
  .skills__grid {
    grid-template-columns: 1fr;
  }

  /* Timeline Mobile */
  .timeline {
    padding-left: var(--space-xl);
  }

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

  .timeline__period {
    align-self: flex-start;
  }

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

  /* Education Mobile */
  .education__grid {
    grid-template-columns: 1fr;
  }

  /* Certs Mobile */
  .certs__grid {
    grid-template-columns: 1fr;
  }

  /* Gallery Mobile */
  .gallery__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-sm);
  }

  /* Contact Mobile */
  .contact__links {
    flex-direction: column;
    align-items: center;
  }

  .contact__item {
    width: 100%;
    max-width: 360px;
    justify-content: center;
  }

  /* Footer Mobile */
  .footer__container {
    flex-direction: column;
    gap: var(--space-sm);
    text-align: center;
  }
}

/* ============================================
   MEDIA QUERIES: SMALL MOBILE (<=480px)
   ============================================ */
@media (max-width: 480px) {
  .hero__name {
    font-size: var(--font-size-2xl);
  }

  .hero__image img {
    width: 160px;
    height: 160px;
  }

  .btn {
    padding: 0.625rem 1.25rem;
    font-size: var(--font-size-sm);
  }

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