:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --secondary: #0f172a;
  --accent: #f97316;
  --light: #f8fafc;
  --dark: #0f172a;
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --gray-900: #0f172a;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --border-radius: 8px;
  --transition: all 0.3s ease;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --max-width: 1200px;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
}

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

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

body {
  font-family: var(--font-main);
  line-height: 1.6;
  color: var(--dark);
  background-color: var(--light);
}

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

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

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

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background-color: var(--primary);
  color: white;
  border: none;
  border-radius: var(--border-radius);
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  font-size: 1rem;
}

.btn:hover {
  background-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

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

.btn--secondary:hover {
  background-color: var(--gray-800);
}

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

.btn--accent:hover {
  background-color: #ea580c;
}

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

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

.btn--small {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}

.btn--large {
  padding: 1rem 2rem;
  font-size: 1.125rem;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.card {
  background: white;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: var(--transition);
}

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

.card__image {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.card__content {
  padding: var(--spacing-lg);
}

.card__title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--dark);
}

.card__text {
  color: var(--gray-600);
  margin-bottom: var(--spacing-md);
}

.card--teacher .card__image {
  height: 250px;
}

.form {
  background: white;
  padding: var(--spacing-xl);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
}

.form__group {
  margin-bottom: var(--spacing-lg);
}

.form__label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  color: var(--gray-700);
}

.form__input,
.form__textarea,
.form__select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--gray-300);
  border-radius: var(--border-radius);
  font-family: var(--font-main);
  font-size: 1rem;
  transition: var(--transition);
}

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

.form__textarea {
  min-height: 150px;
  resize: vertical;
}

.form__error {
  color: var(--error);
  font-size: 0.875rem;
  margin-top: var(--spacing-xs);
  display: block;
}

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

.alert {
  padding: 1rem;
  border-radius: var(--border-radius);
  margin-bottom: var(--spacing-lg);
}

.alert--success {
  background-color: #d1fae5;
  color: #065f46;
  border: 1px solid #10b981;
}

.alert--error {
  background-color: #fee2e2;
  color: #991b1b;
  border: 1px solid #ef4444;
}

.alert--warning {
  background-color: #fef3c7;
  color: #92400e;
  border: 1px solid #f59e0b;
}

.alert--info {
  background-color: #dbeafe;
  color: #1e40af;
  border: 1px solid #3b82f6;
}

.header {
  background-color: white;
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) 0;
}

.nav__logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--dark);
}

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

.nav__menu {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--spacing-lg);
}

.nav__item a {
  font-weight: 500;
  color: var(--gray-700);
  padding: 0.5rem;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.nav__item a:hover,
.nav__item a.active {
  color: var(--primary);
  background-color: rgba(37, 99, 235, 0.1);
}

.nav__item--auth {
  display: flex;
  gap: var(--spacing-sm);
}

.nav__toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--dark);
}

.footer {
  background-color: var(--dark);
  color: white;
  padding: var(--spacing-xl) 0;
  margin-top: var(--spacing-2xl);
}

.footer__content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-xl);
}

.footer__section h3 {
  margin-bottom: var(--spacing-md);
  font-size: 1.25rem;
}

.footer__section ul {
  list-style: none;
}

.footer__section li {
  margin-bottom: var(--spacing-sm);
}

.footer__section a {
  color: var(--gray-300);
}

.footer__section a:hover {
  color: white;
}

.footer__bottom {
  text-align: center;
  padding-top: var(--spacing-xl);
  margin-top: var(--spacing-xl);
  border-top: 1px solid var(--gray-800);
  color: var(--gray-400);
  font-size: 0.875rem;
}

.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: white;
  padding: var(--spacing-2xl) 0;
  text-align: center;
}

.hero__content {
  max-width: 800px;
  margin: 0 auto;
}

.hero__title {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  line-height: 1.2;
}

.hero__subtitle {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-xl);
  opacity: 0.9;
}

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

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

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

.section__title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: var(--spacing-sm);
}

.section__subtitle {
  font-size: 1.125rem;
  color: var(--gray-600);
  max-width: 700px;
  margin: 0 auto;
}

.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid--programs {
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.grid--teachers {
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

.grid--courses {
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
}

.grid--posts {
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
}

.pagination {
  display: flex;
  justify-content: center;
  margin-top: var(--spacing-xl);
  gap: var(--spacing-sm);
}

.pagination__item {
  list-style: none;
}

.pagination__link {
  display: block;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--gray-300);
  border-radius: var(--border-radius);
  color: var(--gray-700);
  transition: var(--transition);
}

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

.table {
  width: 100%;
  border-collapse: collapse;
  background: white;
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.table th,
.table td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--gray-200);
}

.table th {
  background-color: var(--gray-100);
  font-weight: 600;
  color: var(--gray-700);
}

.table tr:last-child td {
  border-bottom: none;
}

.table tr:hover {
  background-color: var(--gray-100);
}

.dashboard {
  display: grid;
  grid-template-columns: 250px 1fr;
  min-height: calc(100vh - 200px);
}

.sidebar {
  background-color: var(--dark);
  color: white;
  padding: var(--spacing-lg) 0;
}

.sidebar__nav {
  list-style: none;
}

.sidebar__item {
  margin-bottom: var(--spacing-sm);
}

.sidebar__link {
  display: block;
  padding: 0.75rem var(--spacing-lg);
  color: var(--gray-300);
  transition: var(--transition);
  border-left: 3px solid transparent;
}

.sidebar__link:hover,
.sidebar__link.active {
  background-color: rgba(255, 255, 255, 0.1);
  color: white;
  border-left-color: var(--primary);
}

.main-content {
  padding: var(--spacing-xl);
  background-color: var(--gray-100);
}

.dashboard__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-xl);
}

.dashboard__title {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--dark);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.stat-card {
  background: white;
  padding: var(--spacing-lg);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.stat-card__icon {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.stat-card--courses .stat-card__icon {
  background-color: rgba(37, 99, 235, 0.1);
  color: var(--primary);
}

.stat-card--teachers .stat-card__icon {
  background-color: rgba(249, 115, 22, 0.1);
  color: var(--accent);
}

.stat-card--students .stat-card__icon {
  background-color: rgba(16, 185, 129, 0.1);
  color: var(--success);
}

.stat-card__info h3 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
}

.stat-card__info p {
  color: var(--gray-600);
  font-size: 0.875rem;
}

.content-section {
  background: white;
  padding: var(--spacing-xl);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  margin-bottom: var(--spacing-lg);
}

.content-section__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--gray-200);
}

.content-section__title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--dark);
}

.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: var(--spacing-lg);
}

.gallery__item {
  border-radius: var(--border-radius);
  overflow: hidden;
  position: relative;
  aspect-ratio: 4/3;
}

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

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

.schedule {
  background: white;
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.schedule__header {
  display: grid;
  grid-template-columns: 1fr 2fr 2fr 1fr;
  background-color: var(--gray-100);
  font-weight: 600;
  padding: 1rem;
}

.schedule__row {
  display: grid;
  grid-template-columns: 1fr 2fr 2fr 1fr;
  border-bottom: 1px solid var(--gray-200);
  padding: 1rem;
}

.schedule__row:last-child {
  border-bottom: none;
}

.schedule__time {
  font-weight: 500;
}

.schedule__course {
  font-weight: 600;
  color: var(--primary);
}

.schedule__teacher {
  color: var(--gray-600);
}

.blog-post {
  background: white;
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  margin-bottom: var(--spacing-lg);
}

.blog-post__image {
  height: 200px;
  object-fit: cover;
}

.blog-post__content {
  padding: var(--spacing-lg);
}

.blog-post__title {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-sm);
}

.blog-post__meta {
  color: var(--gray-500);
  font-size: 0.875rem;
  margin-bottom: var(--spacing-md);
}

.blog-post__excerpt {
  color: var(--gray-700);
  margin-bottom: var(--spacing-md);
}

.post-content {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--spacing-xl) 0;
}

.post-content h1,
.post-content h2,
.post-content h3 {
  margin: 1.5rem 0 1rem;
  color: var(--dark);
}

.post-content h1 {
  font-size: 2.5rem;
}

.post-content h2 {
  font-size: 2rem;
}

.post-content h3 {
  font-size: 1.5rem;
}

.post-content p {
  margin-bottom: 1.5rem;
  line-height: 1.8;
}

.post-content img {
  margin: 2rem auto;
  border-radius: var(--border-radius);
}

@media (max-width: 768px) {
  .nav__menu {
    position: fixed;
    top: 70px;
    left: -100%;
    flex-direction: column;
    background: white;
    width: 100%;
    text-align: center;
    transition: 0.3s;
    box-shadow: var(--shadow);
    padding: var(--spacing-lg) 0;
  }

  .nav__menu.active {
    left: 0;
  }

  .nav__toggle {
    display: block;
  }

  .nav__item--auth {
    flex-direction: column;
    gap: var(--spacing-xs);
  }

  .hero__title {
    font-size: 2rem;
  }

  .hero__subtitle {
    font-size: 1rem;
  }

  .section__title {
    font-size: 1.75rem;
  }

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

  .sidebar {
    position: fixed;
    left: -100%;
    top: 70px;
    height: calc(100vh - 70px);
    transition: 0.3s;
    z-index: 99;
  }

  .sidebar.active {
    left: 0;
  }

  .main-content {
    padding: var(--spacing-lg);
  }

  .schedule__header,
  .schedule__row {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
  }

  .schedule__header:nth-child(3),
  .schedule__header:nth-child(4),
  .schedule__row:nth-child(3),
  .schedule__row:nth-child(4) {
    display: none;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-sm);
  }

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

  .hero__title {
    font-size: 1.75rem;
  }

  .hero__actions {
    flex-direction: column;
    align-items: center;
  }

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

  .section__title {
    font-size: 1.5rem;
  }

  .grid--programs,
  .grid--teachers,
  .grid--courses,
  .grid--posts {
    grid-template-columns: 1fr;
  }

  .form {
    padding: var(--spacing-lg);
  }

  .dashboard__header {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-md);
  }

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