:root {
  --primary-color: #4e54c8;
  --secondary-color: #8f94fb;
  --accent-color: #ff6b6b;
  --light-color: #f8f9fa;
  --dark-color: #212529;
}

body {
  background: linear-gradient(
    to right,
    var(--primary-color),
    var(--secondary-color)
  );
  min-height: 100vh;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  color: var(--dark-color);
}

.main-container {
  background-color: rgba(255, 255, 255, 0.95);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
  overflow: hidden;
}

.app-header {
  margin-top: 0.7rem;
  background: linear-gradient(
    to right,
    var(--primary-color),
    var(--secondary-color)
  );
  color: white;
  padding: 2rem;
  text-align: center;
  border-radius: 15px;
}

.app-header h1 {
  font-weight: 700;
  margin-bottom: 0.5rem;
}

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

.form-section {
  padding: 2rem;
  border-bottom: 1px solid #e9ecef;
}

.bookmarks-section {
  padding: 1rem 0px;
}

.table-responsive {
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

table {
  margin-bottom: 0;
}

thead {
  background-color: var(--primary-color);
  color: white;
}

th {
  font-weight: 600;
  padding: 1rem !important;
}

tr:nth-child(even) {
  background-color: #f8f9fa;
}

.btn-primary {
  background: linear-gradient(
    to right,
    var(--primary-color),
    var(--secondary-color)
  );
  border: none;
  padding: 0.5rem 1.5rem;
  transition: all 0.3s;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.btn-visit {
  background-color: #20c997;
  color: white;
  transition: all 0.3s;
}

.btn-visit:hover {
  background-color: #199d75;
  color: white;
}

.btn-delete {
  background-color: var(--accent-color);
  color: white;
  transition: all 0.3s;
}

.btn-delete:hover {
  background-color: #ec3948;
  color: white;
}

.modal-content {
  border-radius: 15px;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.modal-header {
  background: linear-gradient(
    to right,
    var(--primary-color),
    var(--secondary-color)
  );
  color: white;
}

.form-control:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 0.25rem rgba(78, 84, 200, 0.25);
}

.empty-state {
  text-align: center;
  padding: 3rem;
  color: #6c757d;
}

.empty-state i {
  font-size: 5rem;
  margin-bottom: 1rem;
  color: #ced4da;
}

.validation-icon {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  right: 15px;
  font-size: 1.2rem;
  display: none;
}

.is-valid + .validation-icon .bi-check-circle-fill {
  display: inline;
  color: #198754;
}

.is-invalid + .validation-icon .bi-exclamation-circle-fill {
  display: inline;
  color: #dc3545;
}

.input-group {
  position: relative;
}

@media (min-width: 768px) {
  .app-header h1 {
    font-size: 1.8rem;
  }

  .form-section,
  .bookmarks-section {
    padding: 1.5rem;
  }
}

@media (min-width: 576px) {
  .main-container {
    margin-top: 3rem;
    margin-bottom: 3rem;
    border-radius: 15px;
  }
}