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

body {
  background: linear-gradient(135deg, #e0f4ff 0%, #fff9e6 50%, #e8f5e9 100%);
  font-family: 'Arial', sans-serif;
  padding: 20px;
  min-height: 100vh;
}


.container {
  max-width: 1400px;
  margin: 0 auto;
}

.logo {
  display: block;
  max-width: 350px;
  height: auto;
  margin: 0 auto 30px;
}

h1 {
  text-align: center;
  color: #5a7fb3;
  font-size: 2.5em;
  margin-bottom: 50px;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
  font-weight: bold;
}

.grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 25px;
  margin-bottom: 40px;
}

.video-card {
  border-radius: 15px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  cursor: pointer;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 150px;
  padding: 20px;
  text-align: center;
}

.video-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.video-card .student-name {
  font-weight: bold;
  color: #333;
  font-size: 1.3em;
  text-shadow: 1px 1px 1px rgba(255, 255, 255, 0.5);
}

/* Gradient color options */
.gradient-1 {
  background: linear-gradient(135deg, #b3e5fc 0%, #80deea 100%);
}

.gradient-2 {
  background: linear-gradient(135deg, #fff9c4 0%, #ffeb3b 100%);
}

.gradient-3 {
  background: linear-gradient(135deg, #c8e6c9 0%, #a5d6a7 100%);
}

.gradient-4 {
  background: linear-gradient(135deg, #bbdefb 0%, #64b5f6 100%);
}

.gradient-5 {
  background: linear-gradient(135deg, #ffe0b2 0%, #ffcc80 100%);
}

.gradient-6 {
  background: linear-gradient(135deg, #d1c4e9 0%, #b39ddb 100%);
}

.gradient-7 {
  background: linear-gradient(135deg, #f8bbd0 0%, #f48fb1 100%);
}

.gradient-8 {
  background: linear-gradient(135deg, #b2dfdb 0%, #80cbc4 100%);
}

/* Modal for video playback */
.modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
}

.modal.active {
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-content {
  position: relative;
  background-color: #fff;
  padding: 20px;
  border-radius: 15px;
  width: 90%;
  max-width: 800px;
  max-height: 90vh;
  overflow: auto;
}

.close {
  position: absolute;
  right: 20px;
  top: 10px;
  font-size: 28px;
  font-weight: bold;
  color: #5a7fb3;
  cursor: pointer;
}

.close:hover {
  color: #000;
}

iframe {
  width: 100%;
  height: 500px;
  border: none;
  border-radius: 10px;
}

.modal-title {
  text-align: center;
  color: #5a7fb3;
  margin-top: 15px;
  font-size: 1.5em;
  font-weight: bold;
}

/* Responsive */
@media (max-width: 1024px) {
  .grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  h1 {
    font-size: 2em;
  }
  
  iframe {
    height: 350px;
  }
}

@media (max-width: 480px) {
  .grid {
    grid-template-columns: 1fr;
  }
  
  h1 {
    font-size: 1.5em;
  }
  
  .logo {
    max-width: 250px;
  }
  
  iframe {
    height: 250px;
  }
}