body {
    font-family: 'Inter', sans-serif;
    background-color: #f0f4f8; /* Light blue-gray background */
}
.code-font {
    font-family: 'Fira Code', monospace;
    font-variant-ligatures: none;
}
.input-correct {
    border-color: #22c55e; /* green-500 */
    background-color: #f0fdf4; /* green-50 */
}
.input-locked {
    background-color: #f1f5f9; /* slate-100 */
    color: #64748b; /* slate-500 */
}
.tick-mark {
    color: #22c55e; /* green-500 */
    font-weight: bold;
    font-size: 1.5rem;
    opacity: 0;
    transition: opacity 0.3s ease-in-out;
}
.tick-mark.visible {
    opacity: 1;
}
.modal-backdrop {
    background-color: rgba(0, 0, 0, 0.5);
}
/* Style for the active program line */
.active-line {
    background-color: #475569; /* slate-600 */
    border-left: 3px solid #38bdf8; /* sky-400 */
}
input:disabled {
  background-color: #e2e8f0; /* slate-200 */
}