/**
 * 可访问性样式
 * 增强键盘导航和屏幕阅读器支持
 */

/* 屏幕阅读器专用内容 */
.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;
}

/* 跳转链接 */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    z-index: 10000;
    padding: 8px 16px;
    background: #6666ff;
    color: white;
    text-decoration: none;
    border-radius: 0 0 4px 0;
    font-weight: bold;
    transition: top 0.2s;
}

.skip-link:focus {
    top: 0;
    outline: 3px solid #ffcc00;
    outline-offset: 2px;
}

/* 键盘导航模式 - 增强焦点可见性 */
body.keyboard-mode *:focus {
    outline: 3px solid #6666ff !important;
    outline-offset: 2px;
}

body.keyboard-mode button:focus,
body.keyboard-mode .control-btn:focus {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
    box-shadow: 0 0 0 4px rgba(102, 102, 255, 0.2);
}

/* 增强按钮焦点样式 */
button:focus-visible,
.control-btn:focus-visible,
.header-icon-btn:focus-visible {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
    box-shadow: 0 0 0 4px rgba(102, 102, 255, 0.2);
}

/* 链接焦点样式 */
a:focus-visible {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
    text-decoration: underline;
}

/* 输入框焦点样式 */
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
    outline: 3px solid #6666ff;
    outline-offset: 1px;
    border-color: #6666ff;
}

/* 进度条键盘焦点 */
.progress-bar:focus {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
}

/* 音量滑块焦点 */
.volume-slider:focus {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
}

/* 分类卡片键盘焦点 */
.category-card:focus {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(102, 102, 255, 0.3);
}

/* 音轨项键盘焦点 */
.track-item:focus {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
    background: rgba(102, 102, 255, 0.2);
}

/* 模态框关闭按钮焦点 */
.close:focus {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
    color: #6666ff;
}

/* 减少动画以适应用户偏好 */
@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;
    }

    /* 保持Canvas动画完全禁用 */
    #backgroundCanvas {
        display: none;
    }
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
    body {
        background: #000;
        color: #fff;
    }

    .category-card {
        border: 2px solid #fff;
    }

    button,
    .control-btn {
        border: 2px solid #fff;
    }
}

/* 深色模式偏好 */
@media (prefers-color-scheme: dark) {
    /* 应用已经是深色主题，无需额外样式 */
}

/* 焦点指示器增强 - 确保在所有背景下可见 */
:focus-visible {
    outline: 3px solid #6666ff;
    outline-offset: 2px;
}

/* 禁用默认焦点样式（使用focus-visible替代） */
:focus:not(:focus-visible) {
    outline: none;
}

/* 键盘快捷键提示 */
.keyboard-hint {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 8px 12px;
    background: rgba(102, 102, 255, 0.9);
    color: white;
    border-radius: 4px;
    font-size: 12px;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
    z-index: 9999;
}

body.keyboard-mode .keyboard-hint {
    opacity: 1;
}

/* 无障碍文本大小 */
@media (min-width: 768px) {
    .category-name {
        font-size: 1.1rem; /* 确保文字大小适中 */
    }

    .track-title {
        font-size: 1rem;
    }
}

/* 触摸目标大小（WCAG 2.5.5） */
button,
.control-btn,
.header-icon-btn,
.category-card,
.track-item {
    min-height: 44px;
    min-width: 44px;
}

/* 确保足够的颜色对比度 */
.subtitle {
    color: rgba(255, 255, 255, 0.85); /* 提高对比度 */
}

.track-category {
    color: rgba(255, 255, 255, 0.75); /* 提高对比度 */
}

/* 语音识别辅助 */
[role="button"],
[role="link"] {
    cursor: pointer;
}

/* ARIA实时区域样式 */
[aria-live] {
    position: absolute;
    left: -10000px;
    width: 1px;
    height: 1px;
    overflow: hidden;
}

/* 加载状态可访问性 */
[aria-busy="true"] {
    cursor: wait;
    opacity: 0.6;
}

/* 禁用状态 */
[aria-disabled="true"],
[disabled] {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

/* 确保交互元素可点击区域足够大 */
.close {
    padding: 10px;
    min-width: 44px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

/* 语言选择器可访问性 */
.language-selector select {
    padding: 8px 12px;
    min-height: 44px;
}

/* 播放按钮大尺寸 */
.play-btn {
    min-width: 60px;
    min-height: 60px;
    font-size: 24px;
}