/* ========================================
   Shared Animations & Loading
   Deduplicated @keyframes + spinner/skeleton
   ======================================== */

/* ----- 공통 애니메이션 ----- */

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

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

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    20%, 60% { transform: translateX(-5px); }
    40%, 80% { transform: translateX(5px); }
}

@keyframes slideDown {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

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

/* ----- 로딩 스피너 ----- */

.loading-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 60px 20px;
    color: var(--text-secondary);
    min-height: 200px;
    grid-column: 1 / -1;
}

.loading-container p {
    font-family: var(--font-mono);
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-top: 16px;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--cyan-10);
    border-top: 3px solid var(--neon-cyan);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.loading-spinner.hidden,
.loading-container.hidden {
    display: none;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 3px solid var(--cyan-10);
    border-top: 3px solid var(--neon-cyan);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 16px;
}

/* ----- 스켈레톤 로딩 ----- */

.skeleton-text {
    color: var(--text-muted);
    opacity: 0.5;
}

.problem-item.skeleton-item {
    padding: 16px 20px;
    margin-bottom: 4px;
    background: var(--bg-secondary);
    border-radius: 6px;
    border: 1px solid transparent;
    pointer-events: none;
}

.skeleton-line {
    height: 16px;
    width: 60%;
    background: linear-gradient(
        90deg,
        var(--bg-elevated) 25%,
        var(--cyan-05) 50%,
        var(--bg-elevated) 75%
    );
    background-size: 200% 100%;
    animation: skeleton-shimmer 1.5s infinite;
    border-radius: 4px;
}

.problem-item.skeleton-item:nth-child(2) .skeleton-line {
    width: 75%;
}

.problem-item.skeleton-item:nth-child(3) .skeleton-line {
    width: 50%;
}