/* ===== CSS CUSTOM PROPERTIES ===== */
:root {
  /* Colors */
  --primary-color: #2563eb;
  --primary-color-alt: #1d4ed8;
  --secondary-color: #64748b;
  --accent-color: #f59e0b;
  --success-color: #10b981;
  --error-color: #ef4444;
  
  /* Light theme colors */
  --bg-color: #ffffff;
  --bg-color-alt: #f8fafc;
  --text-color: #1e293b;
  --text-color-light: #64748b;
  --border-color: #e2e8f0;
  --shadow-color: rgba(0, 0, 0, 0.08);
  --shadow-color-hover: rgba(0, 0, 0, 0.12);
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-heading: 'Space Grotesk', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 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: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Layout */
  --container-width: 1200px;
  --border-radius: 0.5rem;
  --border-radius-lg: 1rem;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --header-height: 70px;
  
  /* Z-index */
  --z-tooltip: 10;
  --z-fixed: 100;
  --z-modal: 1000;
}

/* Dark theme */
[data-theme="dark"] {
  --bg-color: #0f172a;
  --bg-color-alt: #1e293b;
  --text-color: #f1f5f9;
  --text-color-light: #94a3b8;
  --border-color: #334155;
  --shadow-color: rgba(0, 0, 0, 0.25);
  --shadow-color-hover: rgba(0, 0, 0, 0.35);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  color: var(--text-color);
  background-color: var(--bg-color);
  line-height: 1.6;
  transition: var(--transition);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

/* ===== ACCESSIBILITY ===== */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--primary-color);
  color: white;
  padding: 8px 16px;
  text-decoration: none;
  border-radius: var(--border-radius);
  z-index: var(--z-modal);
  font-weight: 500;
  transition: top 0.3s ease;
}

.skip-link:focus {
  top: 6px;
}

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

/* Remove focus outline for mouse users */
:focus:not(:focus-visible) {
  outline: none;
}

/* ===== UTILITY CLASSES ===== */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  width: 100%;
}

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

.section__header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section__subtitle {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--primary-color);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--spacing-sm);
  display: block;
}

.section__title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--text-color);
  margin-bottom: var(--spacing-lg);
  line-height: 1.2;
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-lg);
  border: none;
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  min-height: 44px;
  min-width: 44px;
  font-family: inherit;
}

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

.btn--primary:hover,
.btn--primary:focus-visible {
  background: var(--primary-color-alt);
  transform: translateY(-2px);
  box-shadow: 0 10px 25px var(--shadow-color-hover);
}

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

.btn--secondary:hover,
.btn--secondary:focus-visible {
  background: var(--bg-color-alt);
  transform: translateY(-2px);
}

.btn--large {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-lg);
}

.btn--full {
  width: 100%;
}

.btn__icon {
  font-size: var(--font-size-lg);
  transition: var(--transition);
}

.btn:hover .btn__icon {
  transform: translateX(4px);
}

/* ===== HEADER & NAVIGATION ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  z-index: var(--z-fixed);
  height: var(--header-height);
  transition: var(--transition);
}

[data-theme="dark"] .header {
  background: rgba(15, 23, 42, 0.95);
}

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

.nav__logo {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--text-color);
  text-decoration: none;
  transition: var(--transition);
}

.nav__logo:hover,
.nav__logo:focus-visible {
  color: var(--primary-color);
}

.nav__menu {
  display: flex;
  align-items: center;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
  list-style: none;
}

.nav__link {
  color: var(--text-color);
  text-decoration: none;
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
  transition: var(--transition);
  position: relative;
}

.nav__link:hover,
.nav__link:focus-visible {
  color: var(--primary-color);
  background: var(--bg-color-alt);
}

.nav__link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--primary-color);
  transition: var(--transition);
  transform: translateX(-50%);
}

.nav__link:hover::after {
  width: 80%;
}

/* Theme toggle button */
.theme-toggle {
  background: none;
  border: none;
  font-size: var(--font-size-xl);
  cursor: pointer;
  padding: var(--spacing-xs);
  border-radius: var(--border-radius);
  transition: var(--transition);
  min-height: 44px;
  min-width: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-color);
}

.theme-toggle:hover,
.theme-toggle:focus-visible {
  background: var(--bg-color-alt);
  transform: scale(1.1);
}

/* Mobile navigation */
.nav__toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 4px;
  padding: var(--spacing-xs);
  min-height: 44px;
  min-width: 44px;
  justify-content: center;
  background: none;
  border: none;
}

.nav__toggle-icon {
  width: 25px;
  height: 3px;
  background: var(--text-color);
  transition: var(--transition);
  border-radius: 2px;
}

/* Mobile navigation states */
.nav__toggle.active .nav__toggle-icon:nth-child(1) {
  transform: rotate(45deg) translate(6px, 6px);
}

.nav__toggle.active .nav__toggle-icon:nth-child(2) {
  opacity: 0;
}

.nav__toggle.active .nav__toggle-icon:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}

/* ===== HERO SECTION ===== */
.hero {
  padding-top: calc(var(--header-height) + var(--spacing-3xl));
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
}

.hero__container {
  position: relative;
}

.hero__content {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

.hero__image-container {
  position: relative;
}

.hero__image {
  width: 300px;
  height: 300px;
  border-radius: 50%;
  object-fit: cover;
  border: 5px solid var(--primary-color);
  box-shadow: 0 20px 40px var(--shadow-color);
  transition: var(--transition);
}

.hero__image:hover {
  transform: scale(1.05);
  box-shadow: 0 25px 50px var(--shadow-color-hover);
}

.hero__image-decoration {
  position: absolute;
  top: -20px;
  right: -20px;
  width: 60px;
  height: 60px;
  background: var(--accent-color);
  border-radius: 50%;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-15px); }
}

.hero__greeting {
  font-size: var(--font-size-lg);
  color: var(--text-color-light);
  margin-bottom: var(--spacing-sm);
  display: block;
}

.hero__title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-5xl);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-lg);
  color: var(--text-color);
}

.hero__highlight {
  color: var(--primary-color);
  position: relative;
}

.hero__highlight::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
  animation: highlight 2s ease-in-out infinite;
}

@keyframes highlight {
  0%, 100% { opacity: 0.7; }
  50% { opacity: 1; }
}

.hero__description {
  font-size: var(--font-size-lg);
  color: var(--text-color-light);
  margin-bottom: var(--spacing-xl);
  max-width: 600px;
}

.hero__buttons {
  display: flex;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

.hero__scroll {
  position: absolute;
  bottom: var(--spacing-xl);
  left: 50%;
  transform: translateX(-50%);
}

.hero__scroll-link {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-decoration: none;
  color: var(--text-color-light);
  font-size: var(--font-size-sm);
  transition: var(--transition);
}

.hero__scroll-link:hover,
.hero__scroll-link:focus-visible {
  color: var(--primary-color);
}

.hero__scroll-icon {
  font-size: var(--font-size-xl);
  margin-top: var(--spacing-xs);
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
  40% { transform: translateY(-10px); }
  60% { transform: translateY(-5px); }
}

/* ===== ABOUT SECTION ===== */
.about {
  background: var(--bg-color-alt);
}

.about__description {
  font-size: var(--font-size-lg);
  color: var(--text-color-light);
  margin-bottom: var(--spacing-xl);
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.about__skills {
  margin-top: var(--spacing-3xl);
}

.skills__title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-2xl);
  font-weight: 600;
  text-align: center;
  margin-bottom: var(--spacing-xl);
  color: var(--text-color);
}

.skills__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
}

.skill__category {
  background: var(--bg-color);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-lg);
  box-shadow: 0 10px 30px var(--shadow-color);
  transition: var(--transition);
}

.skill__category:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 40px var(--shadow-color-hover);
}

.skill__category-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--primary-color);
}

.skill__list {
  list-style: none;
}

.skill__list li {
  padding: var(--spacing-xs) 0;
  color: var(--text-color-light);
  position: relative;
  padding-left: var(--spacing-lg);
}

.skill__list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--success-color);
  font-weight: bold;
}

.about__vision {
  margin-top: var(--spacing-3xl);
  background: var(--bg-color);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-lg);
  box-shadow: 0 10px 30px var(--shadow-color);
  text-align: center;
}

.vision__title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-2xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--primary-color);
}

.vision__text {
  font-size: var(--font-size-lg);
  color: var(--text-color-light);
  max-width: 700px;
  margin: 0 auto;
}

/* ===== EXPERIENCE SECTION ===== */
.timeline {
  position: relative;
  margin-bottom: var(--spacing-3xl);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border-color);
  transform: translateX(-50%);
}

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

.timeline__item:nth-child(odd) .timeline__content {
  margin-right: calc(50% + 30px);
  text-align: right;
}

.timeline__item:nth-child(even) .timeline__content {
  margin-left: calc(50% + 30px);
}

.timeline__marker {
  position: absolute;
  left: 50%;
  top: 20px;
  width: 15px;
  height: 15px;
  background: var(--primary-color);
  border-radius: 50%;
  transform: translateX(-50%);
  border: 3px solid var(--bg-color);
  box-shadow: 0 0 0 3px var(--border-color);
}

.timeline__content {
  background: var(--bg-color);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-lg);
  box-shadow: 0 10px 30px var(--shadow-color);
  transition: var(--transition);
}

.timeline__content:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 40px var(--shadow-color-hover);
}

.timeline__period {
  font-size: var(--font-size-sm);
  color: var(--primary-color);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.timeline__title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin: var(--spacing-sm) 0;
  color: var(--text-color);
}

.timeline__company {
  font-size: var(--font-size-lg);
  color: var(--text-color-light);
  margin-bottom: var(--spacing-md);
}

.timeline__description {
  color: var(--text-color-light);
  margin-bottom: var(--spacing-md);
  line-height: 1.6;
}

.timeline__technologies {
  display: flex;
  gap: var(--spacing-xs);
  flex-wrap: wrap;
  justify-content: flex-start;
}

.timeline__item:nth-child(odd) .timeline__technologies {
  justify-content: flex-end;
}

.tech-tag {
  background: var(--primary-color);
  color: white;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
  font-size: var(--font-size-xs);
  font-weight: 500;
}

.education {
  margin-top: var(--spacing-3xl);
}

.education__title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-2xl);
  font-weight: 600;
  text-align: center;
  margin-bottom: var(--spacing-xl);
  color: var(--text-color);
}

.education__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
}

.education__item {
  background: var(--bg-color);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-lg);
  box-shadow: 0 10px 30px var(--shadow-color);
  text-align: center;
  transition: var(--transition);
}

.education__item:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 40px var(--shadow-color-hover);
}

.education__degree {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--text-color);
}

.education__school {
  color: var(--text-color-light);
  margin-bottom: var(--spacing-sm);
}

.education__period {
  font-size: var(--font-size-sm);
  color: var(--primary-color);
  font-weight: 600;
}

/* ===== PROJECTS SECTION ===== */
.projects {
  background: var(--bg-color-alt);
}

.projects__container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--spacing-xl);
}

.project__card {
  background: var(--bg-color);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: 0 10px 30px var(--shadow-color);
  transition: var(--transition);
}

.project__card:hover {
  transform: translateY(-10px);
  box-shadow: 0 20px 50px var(--shadow-color-hover);
}

.project__image-container {
  position: relative;
  overflow: hidden;
}

.project__image {
  width: 100%;
  height: 250px;
  object-fit: cover;
  transition: var(--transition);
}

.project__card:hover .project__image {
  transform: scale(1.1);
}

.project__overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: var(--transition);
}

.project__card:hover .project__overlay {
  opacity: 1;
}

.project__links {
  display: flex;
  gap: var(--spacing-md);
}

.project__link {
  background: white;
  color: var(--text-color);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
  min-height: 44px;
  display: flex;
  align-items: center;
}

.project__link:hover,
.project__link:focus-visible {
  background: var(--primary-color);
  color: white;
  transform: translateY(-2px);
}

.project__content {
  padding: var(--spacing-xl);
}

.project__title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-color);
}

.project__description {
  color: var(--text-color-light);
  margin-bottom: var(--spacing-lg);
  line-height: 1.6;
}

.project__technologies {
  display: flex;
  gap: var(--spacing-xs);
  flex-wrap: wrap;
}

/* ===== CONTACT SECTION ===== */
.contact__container {
  max-width: 1000px;
  margin: 0 auto;
}

.contact__content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: start;
}

.contact__info-title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-2xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-color);
}

.contact__info-description {
  font-size: var(--font-size-lg);
  color: var(--text-color-light);
  margin-bottom: var(--spacing-xl);
  line-height: 1.6;
}

.contact__details {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.contact__detail {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--bg-color-alt);
  border-radius: var(--border-radius-lg);
  transition: var(--transition);
}

.contact__detail:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 25px var(--shadow-color);
}

.contact__detail-icon {
  font-size: var(--font-size-2xl);
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--primary-color);
  border-radius: 50%;
  color: white;
  flex-shrink: 0;
}

.contact__detail-title {
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  color: var(--text-color);
}

.contact__detail-link {
  color: var(--primary-color);
  text-decoration: none;
  transition: var(--transition);
}

.contact__detail-link:hover,
.contact__detail-link:focus-visible {
  color: var(--primary-color-alt);
}

/* ===== FORM STYLES ===== */
.contact__form-container {
  background: var(--bg-color-alt);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-lg);
  box-shadow: 0 10px 30px var(--shadow-color);
}

.contact__form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.form__group {
  position: relative;
}

.form__label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
  color: var(--text-color);
}

.form__input,
.form__textarea {
  width: 100%;
  padding: var(--spacing-md);
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  background: var(--bg-color);
  color: var(--text-color);
  transition: var(--transition);
  font-family: inherit;
}

.form__input:focus,
.form__textarea:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form__textarea {
  resize: vertical;
  min-height: 120px;
}

.form__error {
  display: block;
  margin-top: var(--spacing-xs);
  color: var(--error-color);
  font-size: var(--font-size-sm);
  min-height: 20px;
}

.form__input.error,
.form__textarea.error {
  border-color: var(--error-color);
}

.form__success {
  text-align: center;
  padding: var(--spacing-xl);
  background: var(--bg-color);
  border-radius: var(--border-radius-lg);
  border: 2px solid var(--success-color);
}

.success__icon {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--spacing-md);
  display: block;
  color: var(--success-color);
}

.success__title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--success-color);
  margin-bottom: var(--spacing-sm);
}

.success__text {
  color: var(--text-color-light);
}

/* ===== CTA SECTION ===== */
.cta {
  background: linear-gradient(135deg, var(--primary-color), var(--primary-color-alt));
  color: white;
}

.cta__container {
  text-align: center;
}

.cta__title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-4xl);
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
}

.cta__description {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  opacity: 0.9;
}

.cta__buttons {
  display: flex;
  gap: var(--spacing-lg);
  justify-content: center;
  flex-wrap: wrap;
}

.cta .btn--secondary {
  background: white;
  color: var(--primary-color);
  border-color: white;
}

.cta .btn--secondary:hover,
.cta .btn--secondary:focus-visible {
  background: rgba(255, 255, 255, 0.9);
  transform: translateY(-2px);
}

/* ===== FOOTER ===== */
.footer {
  background: var(--bg-color-alt);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer__content {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--spacing-3xl);
  margin-bottom: var(--spacing-xl);
}

.footer__brand {
  text-align: left;
}

.footer__title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-2xl);
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
  color: var(--text-color);
}

.footer__subtitle {
  color: var(--text-color-light);
  font-size: var(--font-size-lg);
}

.footer__links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-xl);
}

.footer__group-title {
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-color);
}

.footer__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.footer__link {
  color: var(--text-color-light);
  text-decoration: none;
  transition: var(--transition);
}

.footer__link:hover,
.footer__link:focus-visible {
  color: var(--primary-color);
  padding-left: var(--spacing-xs);
}

.footer__bottom {
  border-top: 1px solid var(--border-color);
  padding-top: var(--spacing-lg);
  text-align: center;
}

.footer__copy {
  color: var(--text-color-light);
  font-size: var(--font-size-sm);
}

.footer__tagline {
  color: var(--primary-color);
  font-weight: 500;
}

/* ===== BACK TO TOP ===== */
.back-to-top {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  width: 50px;
  height: 50px;
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: 50%;
  font-size: var(--font-size-xl);
  cursor: pointer;
  transition: var(--transition);
  opacity: 0;
  visibility: hidden;
  z-index: var(--z-tooltip);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  min-width: 44px;
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover,
.back-to-top:focus-visible {
  background: var(--primary-color-alt);
  transform: translateY(-5px);
}

/* ===== RESPONSIVE DESIGN ===== */
@media screen and (max-width: 1024px) {
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .section__title {
    font-size: var(--font-size-3xl);
  }
  
  .hero__title {
    font-size: var(--font-size-4xl);
  }
  
  .timeline::before {
    left: 20px;
  }
  
  .timeline__item:nth-child(odd) .timeline__content,
  .timeline__item:nth-child(even) .timeline__content {
    margin-left: 60px;
    margin-right: 0;
    text-align: left;
  }
  
  .timeline__item:nth-child(odd) .timeline__technologies {
    justify-content: flex-start;
  }
  
  .timeline__marker {
    left: 20px;
  }
  
  .contact__content {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
}

@media screen and (max-width: 768px) {
  .nav__menu {
    position: fixed;
    top: var(--header-height);
    left: -100%;
    width: 100%;
    height: calc(100vh - var(--header-height));
    background: var(--bg-color);
    border-top: 1px solid var(--border-color);
    transition: var(--transition);
    padding: var(--spacing-xl);
    overflow-y: auto;
  }
  
  .nav__menu.show {
    left: 0;
  }
  
  .nav__list {
    flex-direction: column;
    gap: var(--spacing-lg);
  }
  
  .nav__toggle {
    display: flex;
  }
  
  .hero__content {
    grid-template-columns: 1fr;
    text-align: center;
    gap: var(--spacing-xl);
  }
  
  .hero__image {
    width: 250px;
    height: 250px;
  }
  
  .hero__title {
    font-size: var(--font-size-3xl);
  }
  
  .hero__buttons {
    justify-content: center;
  }
  
  .section {
    padding: var(--spacing-2xl) 0;
  }
  
  .section__title {
    font-size: var(--font-size-2xl);
  }
  
  .skills__grid {
    grid-template-columns: 1fr;
  }
  
  .projects__container {
    grid-template-columns: 1fr;
  }
  
  .education__grid {
    grid-template-columns: 1fr;
  }
  
  .cta__title {
    font-size: var(--font-size-3xl);
  }
  
  .cta__buttons {
    flex-direction: column;
    align-items: center;
  }
  
  .footer__content {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    text-align: center;
  }
  
  .footer__links {
    grid-template-columns: 1fr;
  }
}

@media screen and (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-sm);
  }
  
  .hero__title {
    font-size: var(--font-size-2xl);
  }
  
  .hero__buttons {
    flex-direction: column;
  }
  
  .projects__container {
    grid-template-columns: 1fr;
  }
  
  .project__links {
    flex-direction: column;
  }
  
  .back-to-top {
    width: 45px;
    height: 45px;
    bottom: var(--spacing-md);
    right: var(--spacing-md);
  }
  
  .section {
    padding: var(--spacing-xl) 0;
  }
  
  .hero {
    padding-top: calc(var(--header-height) + var(--spacing-2xl));
  }
  
  .contact__detail {
    flex-direction: column;
    text-align: center;
    gap: var(--spacing-sm);
  }
}