:root {
  --bg-color: #f8f9fa;
  --text-color: #333;
  --primary-color: #0052cc;
  --primary-hover: #003d99;
  --border-color: #ddd;
  --success-bg: #d4edda;
  --success-color: #155724;
  --error-bg: #f8d7da;
  --error-color: #721c24;
  --status-opened: #28a745;
  --status-closed: #dc3545;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem;
  background-color: #fff;
  min-height: 100vh;
  box-shadow: 0 0 10px rgba(0,0,0,0.05);
}

header {
  border-bottom: 2px solid var(--border-color);
  margin-bottom: 2rem;
}

header h1 {
  margin: 0 0 1rem 0;
  color: var(--primary-color);
}

.alert {
  padding: 1rem;
  border-radius: 4px;
  margin-bottom: 1.5rem;
}

.alert-success {
  background-color: var(--success-bg);
  color: var(--success-color);
  border: 1px solid #c3e6cb;
}

.alert-error {
  background-color: var(--error-bg);
  color: var(--error-color);
  border: 1px solid #f5c6cb;
}

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

.form-group label {
  display: block;
  font-weight: bold;
  margin-bottom: 0.5rem;
}

.form-group select {
  width: 100%;
  padding: 0.5rem;
  font-size: 1rem;
  border: 1px solid var(--border-color);
  border-radius: 4px;
}

.issues-section {
  margin-top: 2rem;
}

.issues-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1rem;
  margin-bottom: 1rem;
}

.issues-header h2 {
  margin: 0;
}

.btn-primary {
  background-color: var(--primary-color);
  color: #fff;
  border: none;
  padding: 0.5rem 1rem;
  font-size: 1rem;
  border-radius: 4px;
  cursor: pointer;
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--primary-hover);
}

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.issue-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.issue-item {
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  margin-bottom: 0.5rem;
  background-color: #fafafa;
}

.issue-item label {
  display: flex;
  align-items: center;
  cursor: pointer;
  width: 100%;
}

.issue-item input[type="checkbox"] {
  margin-right: 1rem;
  transform: scale(1.2);
}

.issue-title {
  flex-grow: 1;
  font-weight: 500;
}

.issue-status {
  font-size: 0.85rem;
  padding: 0.2rem 0.5rem;
  border-radius: 3px;
  color: #fff;
  text-transform: capitalize;
}

.status-opened {
  background-color: var(--status-opened);
}

.status-closed {
  background-color: var(--status-closed);
}