/* ===== Utility Classes ===== */
.hidden {
    display: none !important;
}

.screen {
    display: none !important;
    min-height: 100vh;
}

.screen.active {
    display: block !important;
}

.content-section {
    display: none;
}

.content-section.active {
    display: block;
}

/* ===== Loading Spinner ===== */
.loading-spinner {
    display: inline-block;
    width: 48px;
    height: 48px;
    border: 4px solid var(--gray-200);
    border-top: 4px solid var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* ===== Loading States ===== */
.skeleton {
    background: linear-gradient(90deg, var(--gray-200) 0%, var(--gray-100) 50%, var(--gray-200) 100%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

/* ===== Animations ===== */
.fade-in {
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.slide-up {
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== Focus Visible ===== */
:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* ===== Selection ===== */
::selection {
    background: var(--primary);
    color: var(--on-primary);
}

::-moz-selection {
    background: var(--primary);
    color: var(--on-primary);
}