/* ===== 玻璃卡片 ===== */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    transition: background var(--theme-transition), border-color var(--theme-transition);
}

@supports not (backdrop-filter: blur(12px)) {
    .glass-card {
        background: var(--bg-card);
    }
}

/* ===== 按钮 ===== */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--border-radius-md);
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    color: white;
    font-weight: 600;
    transition: transform var(--transition-duration), box-shadow var(--transition-duration);
    text-align: center;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn:active {
    transform: translateY(0);
}

/* ===== 卡片 ===== */
.card {
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    background: var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-duration), box-shadow var(--transition-duration);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* ===== 模态框 ===== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-index-modal);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-duration), visibility var(--transition-duration);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    max-width: 90%;
    max-height: 90%;
    border-radius: var(--border-radius-md);
    overflow: hidden;
}

.modal-content img {
    max-width: 100%;
    max-height: 90vh;
    object-fit: contain;
}

/* ===== 工具类 ===== */
.flex {
    display: flex;
}

.flex-center {
    display: flex;
    justify-content: center;
    align-items: center;
}

.flex-between {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.flex-column {
    display: flex;
    flex-direction: column;
}

.grid {
    display: grid;
}

.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.text-center {
    text-align: center;
}

.text-gradient {
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.img-cover {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.rounded {
    border-radius: var(--border-radius-md);
}

.circle {
    border-radius: var(--border-radius-round);
}

.shadow {
    box-shadow: var(--shadow-md);
}

/* ===== 动画 ===== */
.fade-in {
    animation: fadeIn 0.5s ease-in;
}

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

@keyframes spin {
    to { transform: rotate(360deg); }
}

img.loaded {
    animation: fadeIn 0.3s ease-in;
}

/* ===== 错误状态 ===== */
.error-state {
    text-align: center;
    padding: var(--spacing-xxl);
    max-width: 400px;
    margin: var(--spacing-xxl) auto;
}

.error-state h2 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.error-state p {
    color: var(--text-secondary);
}

/* ===== 响应式工具类 ===== */
@media screen and (max-width: 767px) {
    .grid-2,
    .grid-3 {
        grid-template-columns: 1fr;
    }
}

@media screen and (min-width: 768px) and (max-width: 1024px) {
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (hover: none) and (pointer: coarse) {
    .card:hover {
        transform: none;
    }
}