/* ============================================
   CSS Custom Properties (Design Tokens)
   ============================================ */

:root {
  /* Colors - Light Theme */
  --color-primary: #2196f3;
  --color-primary-container: #d3e4fd;
  --color-on-primary-container: #0b3d91;
  --color-secondary-container: #e0e0e0;
  --color-on-secondary-container: #1a1a1a;

  --color-surface: #fefefe;
  --color-surface-container: #f3f3f3;
  --color-surface-container-low: rgba(243, 243, 243, 0.1);
  --color-on-surface: #1c1b1f;
  --color-on-surface-variant: #605d62;
  --color-error: #b3261e;

  /* Platform Colors */
  --color-linkedin: #0077b5;
  --color-telegram: #0088cc;
  --color-instagram: #833ab4;

  /* Typography */
  --font-family: 'Inter', system-ui, -apple-system, sans-serif;

  /* Spacing */
  --max-content-width: 1200px;
  --section-spacing: 80px;
  --card-spacing: 24px;

  /* Border Radius */
  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 20px;
  --radius-full: 100px;

  /* Shadows */
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.08), 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.12), 0 2px 8px rgba(0, 0, 0, 0.08);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
}

[data-theme="dark"] {
  --color-primary: #90caf9;
  --color-primary-container: #1a3a5c;
  --color-on-primary-container: #c8e6ff;
  --color-secondary-container: #3a3a3a;
  --color-on-secondary-container: #e0e0e0;

  --color-surface: #1c1b1f;
  --color-surface-container: #2b2930;
  --color-surface-container-low: rgba(43, 41, 48, 0.1);
  --color-on-surface: #e6e1e5;
  --color-on-surface-variant: #cac4cf;
  --color-error: #f2b8b5;

  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.3), 0 1px 3px rgba(0, 0, 0, 0.2);
  --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.4), 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* ============================================
   Reset & Base Styles
   ============================================ */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--color-surface);
  color: var(--color-on-surface);
  line-height: 1.6;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  min-height: 100vh;
}

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

ul {
  list-style: none;
}

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

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

/* ============================================
   Header
   ============================================ */

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-surface);
  transition: background-color var(--transition-normal);
}

.header__container {
  display: flex;
  align-items: center;
  justify-content: center;
  max-width: var(--max-content-width);
  margin: 0 auto;
  padding: 16px 24px;
  position: relative;
}

.header__title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-on-surface);
  transition: color var(--transition-normal);
}

.theme-toggle {
  position: absolute;
  right: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  color: var(--color-on-surface);
  transition: background-color var(--transition-fast), color var(--transition-normal);
}

.theme-toggle:hover {
  background-color: var(--color-surface-container);
}

.theme-toggle__icon--dark {
  display: none;
}

[data-theme="dark"] .theme-toggle__icon--light {
  display: block;
}

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

[data-theme="light"] .theme-toggle__icon--light {
  display: none;
}

[data-theme="light"] .theme-toggle__icon--dark {
  display: block;
}

/* ============================================
   Section Shared Styles
   ============================================ */

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--color-on-surface);
  text-align: center;
  transition: color var(--transition-normal);
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--color-on-surface-variant);
  text-align: center;
  margin-top: 16px;
  transition: color var(--transition-normal);
}

/* ============================================
   Profile Section
   ============================================ */

.profile {
  padding: var(--section-spacing) 24px;
}

.profile__container {
  max-width: var(--max-content-width);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.profile__avatar {
  width: 200px;
  height: 200px;
  border-radius: var(--radius-md);
  object-fit: cover;
}

.profile__name {
  margin-top: 32px;
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  color: var(--color-on-surface);
  transition: color var(--transition-normal);
}

.profile__badge {
  display: inline-block;
  margin-top: 16px;
  padding: 8px 20px;
  background-color: var(--color-primary-container);
  color: var(--color-on-primary-container);
  border-radius: var(--radius-lg);
  font-size: 1.25rem;
  font-weight: 500;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

.profile__bio {
  margin-top: 32px;
  max-width: 700px;
  font-size: 1.125rem;
  color: var(--color-on-surface-variant);
  line-height: 1.6;
  transition: color var(--transition-normal);
}

/* ============================================
   Projects Section
   ============================================ */

.projects {
  padding: 20px 24px;
  background-color: var(--color-surface-container-low);
  transition: background-color var(--transition-normal);
}

.projects__container {
  max-width: var(--max-content-width);
  margin: 0 auto;
}

.projects__grid {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
  margin-top: 64px;
}

/* ============================================
   Project Card
   ============================================ */

.card {
  width: 500px;
  max-width: 100%;
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: box-shadow var(--transition-normal), background-color var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-card-hover);
}

.card__body {
  padding: 20px;
}

.card__title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-on-surface);
  transition: color var(--transition-normal);
}

.card__description {
  margin-top: 12px;
  font-size: 0.9375rem;
  color: var(--color-on-surface-variant);
  line-height: 1.5;
  transition: color var(--transition-normal);
}

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

.tag {
  padding: 6px 12px;
  background-color: var(--color-secondary-container);
  color: var(--color-on-secondary-container);
  border-radius: var(--radius-md);
  font-size: 0.8125rem;
  font-weight: 500;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* ============================================
   Image Carousel
   ============================================ */

.carousel {
  position: relative;
  height: 400px;
  background-color: var(--color-surface-container);
  overflow: hidden;
  transition: background-color var(--transition-normal);
}

.carousel__track {
  display: flex;
  height: 100%;
  transition: transform 0.4s ease;
}

.carousel__track img {
  flex: 0 0 100%;
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.carousel__btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: rgba(0, 0, 0, 0.4);
  color: #fff;
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--transition-fast), background-color var(--transition-fast);
}

.carousel:hover .carousel__btn {
  opacity: 1;
}

.carousel__btn:hover {
  background-color: rgba(0, 0, 0, 0.6);
}

.carousel__btn--prev {
  left: 12px;
}

.carousel__btn--next {
  right: 12px;
}

.carousel__dots {
  position: absolute;
  bottom: 12px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
}

.carousel__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: none;
  background-color: rgba(255, 255, 255, 0.5);
  cursor: pointer;
  padding: 0;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

.carousel__dot--active {
  background-color: #fff;
  transform: scale(1.25);
}

/* ============================================
   Contacts Section
   ============================================ */

.contacts {
  padding: var(--section-spacing) 24px;
}

.contacts__container {
  max-width: var(--max-content-width);
  margin: 0 auto;
}

.contacts__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 64px;
}

.contact-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 24px;
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  text-align: center;
  transition: box-shadow var(--transition-normal), background-color var(--transition-normal), transform var(--transition-normal);
}

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

.contact-card__icon {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
}

.contact-card--linkedin .contact-card__icon {
  background-color: var(--color-linkedin);
}

.contact-card--telegram .contact-card__icon {
  background-color: var(--color-telegram);
}

.contact-card--instagram .contact-card__icon {
  background-color: var(--color-instagram);
}

.contact-card__platform {
  margin-top: 16px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-on-surface);
  transition: color var(--transition-normal);
}

.contact-card__username {
  margin-top: 8px;
  font-size: 1.125rem;
  color: var(--color-on-surface-variant);
  transition: color var(--transition-normal);
}

.contact-card__btn {
  display: inline-block;
  margin-top: 16px;
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  color: #fff;
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: filter var(--transition-fast);
}

.contact-card__btn:hover {
  filter: brightness(1.1);
}

.contact-card--linkedin .contact-card__btn {
  background-color: var(--color-linkedin);
}

.contact-card--telegram .contact-card__btn {
  background-color: var(--color-telegram);
}

.contact-card--instagram .contact-card__btn {
  background-color: var(--color-instagram);
}

/* ============================================
   Footer
   ============================================ */

.footer {
  padding: 32px 24px;
  background-color: var(--color-surface-container-low);
  text-align: center;
  transition: background-color var(--transition-normal);
}

.footer p {
  font-size: 0.9375rem;
  color: var(--color-on-surface-variant);
  transition: color var(--transition-normal);
}

/* ============================================
   Responsive Design
   ============================================ */

/* Tablet (<=800px) */
@media (max-width: 800px) {
  .contacts__grid {
    grid-template-columns: 1fr;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
  }

  .card {
    width: 100%;
  }
}

/* Mobile (<=450px) */
@media (max-width: 450px) {
  .header__title {
    font-size: 1rem;
  }

  .profile {
    padding: 48px 16px;
  }

  .profile__avatar {
    width: 150px;
    height: 150px;
  }

  .profile__bio {
    font-size: 1rem;
  }

  .projects {
    padding: 20px 16px;
  }

  .carousel {
    height: 280px;
  }

  .contacts {
    padding: 48px 16px;
  }

  .section-subtitle {
    font-size: 1rem;
  }
}

/* Prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }
}