:root {
  --primary-color: #4361ee;
  --secondary-color: #3f37c9;
  --accent-color: #4895ef;
  --light-color: #f8f9fa;
  --dark-color: #212529;
  --success-color: #4bb543;
  --error-color: #ff3333;
  --border-radius: 8px;
  --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --transition: all 0.3s ease;
}

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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  background-color: #f5f7ff;
  color: var(--dark-color);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  padding: 1.5rem 0;
  text-align: center;
  box-shadow: var(--box-shadow);
}

header h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

header p {
  font-size: 1.1rem;
  opacity: 0.9;
}

main {
  flex: 1;
  padding: 2rem 1rem;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

.container {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 2rem;
  margin-bottom: 2rem;
}

.form-group {
  margin-bottom: 1.5rem;
}

label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: var(--dark-color);
}

input[type="url"],
input[type="text"] {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid #ddd;
  border-radius: var(--border-radius);
  font-size: 1rem;
  transition: var(--transition);
}

input[type="url"]:focus,
input[type="text"]:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(72, 149, 239, 0.2);
}

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

.btn:hover {
  background-color: var(--secondary-color);
  transform: translateY(-2px);
}

.btn-block {
  display: block;
  width: 100%;
}

.url-list {
  list-style: none;
  margin-top: 2rem;
}

.url-item {
  background-color: var(--light-color);
  border-radius: var(--border-radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  transition: var(--transition);
  border-left: 4px solid var(--accent-color);
}

.url-item:hover {
  transform: translateX(5px);
}

.long-url {
  color: #666;
  word-break: break-all;
  font-size: 0.9rem;
}

.short-url {
  color: var(--primary-color);
  font-weight: 600;
  text-decoration: none;
  word-break: break-all;
}

.short-url:hover {
  text-decoration: underline;
}

.url-stats {
  display: flex;
  gap: 1rem;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: #666;
}

.stat {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.message {
  background-color: rgba(75, 181, 67, 0.1);
  color: var(--success-color);
  padding: 1rem;
  border-radius: var(--border-radius);
  margin-bottom: 1.5rem;
  border-left: 4px solid var(--success-color);
}

.error {
  background-color: rgba(255, 51, 51, 0.1);
  color: var(--error-color);
  padding: 1rem;
  border-radius: var(--border-radius);
  margin-bottom: 1.5rem;
  border-left: 4px solid var(--error-color);
}

footer {
  text-align: center;
  padding: 1.5rem;
  background-color: var(--dark-color);
  color: white;
  margin-top: auto;
}

/* Responsive design */
@media (max-width: 768px) {
  header h1 {
    font-size: 2rem;
  }
  
  .container {
    padding: 1.5rem;
  }
  
  .url-item {
    padding: 1rem;
  }
}

/* Animation */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.container {
  animation: fadeIn 0.5s ease-out;
}