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

body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
  color: #333;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  justify-self: center;
}

.header {
  top: 0;
  left: 0;
  width: 100%;
  background: white;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  z-index: 1000;
  padding: 15px 0;
  transition: all 0.3s ease;
}

.header .container {
  display: grid;
  place-content: center;
  place-items: center;
  grid-template-rows: auto 1fr auto;
}

.logo {
  height: 50px;
}

.nav a {
  margin-left: 20px;
  text-decoration: none;
  color: #333;
}

.nav a:hover {
  color: #007bff;
}

.contact-info {
  display: grid;
  align-items: center;
  gap: 15px;
}

.btn {
  background: #007bff;
  color: white;
  border: none;
  padding: 10px 20px;
  border-radius: 5px;
  cursor: pointer;
}

.btn:hover {
  background: #0056b3;
}

.section {
  padding: 80px 0;
  max-width: 1200px;
  margin: 0 auto;
  text-align: left;
}

.section h2 {
  text-align: center;
  margin-bottom: 40px;
  font-size: 2em;
}

.advantages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.advantage-card {
  background: #f8f9fa;
  padding: 30px;
  border-radius: 10px;
  text-align: center;
}

.advantage-card h3 {
  margin-bottom: 15px;
}

.groups-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
}

.groups-table th,
.groups-table td {
  border: 1px solid #ddd;
  padding: 12px;
  text-align: center;
}

.groups-table th {
  background: #007bff;
  color: white;
}

.prev {
  left: 10px;
}

.next {
  right: 10px;
}

.activities-list {
  list-style-type: disc;
  margin-left: 20px;
}

.activities-list li {
  margin-bottom: 10px;
}

.social-links {
  text-align: center;
  margin-top: 20px;
}

.social-links a {
  margin: 0 10px;
  color: #007bff;
  text-decoration: none;
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: #007bff;
  color: white;
  border: none;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 20px;
  display: none;
}

.modal {
  display: none;
  position: fixed;
  z-index: 2000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
}

.modal-content {
  background: white;
  margin: 5% auto;
  padding: 30px;
  border-radius: 10px;
  max-width: 500px;
  position: relative;
}

.close {
  position: absolute;
  right: 20px;
  top: 10px;
  font-size: 30px;
  cursor: pointer;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 5px;
  font-weight: bold;
}

.form-group input {
  width: 100%;
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}

.error-message {
  color: red;
  font-size: 14px;
  margin-top: 5px;
  display: block;
}

.success-message {
  color: green;
  text-align: center;
  margin-top: 20px;
  display: none;
}

@media (max-width: 768px) {
  .header .container {
    gap: 15px;
  }

  .nav {
    display: grid;
    justify-content: center;
  }

  .nav a {
    margin: 5px;
  }
}

.slider {
  position: relative;
  width: 600px;
  height: 350px;
  margin: 0 auto;
  overflow: hidden;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  transition: opacity 0.5s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: #fff;
}

.slide img {
  max-width: 100%;
  max-height: 70%;
  object-fit: contain;
}

.slide:target,
#slide1:not(:target) {
  opacity: 1;
}

.slider-nav {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  z-index: 10;
}

.nav-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  text-decoration: none;
  align-items: center;
  justify-content: center;
  transition: background 0.3s ease;
}

.nav-dot:hover {
  background: rgba(255, 255, 255, 0.8);
}

.slide:target ~ .slider-nav .nav-dot[href="#slide1"],
#slide1:not(:target) ~ .slider-nav .nav-dot[href="#slide1"] {
  background: white;
}

.slide:target ~ .slider-nav .nav-dot[href="#slide2"],
#slide2:target ~ .slider-nav .nav-dot[href="#slide2"] {
  background: white;
}

.slide:target ~ .slider-nav .nav-dot[href="#slide3"],
#slide3:target ~ .slider-nav .nav-dot[href="#slide3"] {
  background: white;
}