/* === 无障碍访问优化 === */

/* 焦点可见性 */
:focus {
    outline: 3px solid #D4A4B8;
    outline-offset: 2px;
}

/* 键盘导航焦点样式 */
.btn:focus,
.back-btn:focus,
button:focus,
input:focus,
select:focus,
textarea:focus {
    outline: 3px solid #D4A4B8;
    outline-offset: 2px;
    box-shadow: 0 0 0 3px rgba(212, 164, 184, 0.3);
}

/* 跳过导航链接（屏幕阅读器） */
.skip-link {
    position: absolute;
    left: -9999px;  /* ✅ 彻底隐藏在屏幕外 */
    top: auto;
    background: #D4A4B8;
    color: white;
    padding: 8px 16px;
    z-index: 100;
    text-decoration: none;
    border-radius: 0 0 8px 8px;
    transition: left 0.3s ease;  /* ✅ 平滑显示 */
}

.skip-link:focus {
    left: 0;  /* ✅ 键盘焦点时滑入 */
    top: 0;
}

/* 屏幕阅读器专用样式 */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
    .btn,
    .back-btn,
    button {
        border: 2px solid currentColor;
    }
    
    .stat-card {
        border: 2px solid var(--neutral-700);
    }
}

/* 减少动效（用户偏好） */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* 暗黑模式支持（未来扩展） */
@media (prefers-color-scheme: dark) {
    :root {
        --neutral-50: #1A1A1A;
        --neutral-100: #2A2A2A;
        --neutral-700: #E0E0E0;
        --neutral-400: #A0A0A0;
    }
    
    body {
        background: var(--neutral-50);
        color: var(--neutral-700);
    }
}