/**
 * 基础重置 - 全局样式初始化
 * 重置、html/body 默认、按钮/可访问性/减少动画
 */

/* ========== 基础重置 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    color-scheme: dark;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

img, svg, video, canvas {
    max-width: 100%;
    display: block;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: transparent;
    color: inherit;
}

/* ========== 可访问性：键盘焦点环（WCAG AAA 4px）========== */
:focus-visible {
    outline: 3px solid var(--accent-secondary);
    outline-offset: 2px;
    border-radius: var(--radius-xs);
    transition: outline-offset var(--duration-fast) var(--ease-out);
}

button:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
    box-shadow: var(--shadow-focus);
    outline: none;
}

/* 减少动画（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;
    }
}