/* ============================================
 * 基础重置与排版
 * ============================================ */

*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

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

button, input, textarea, select {
    font: inherit;
    color: inherit;
}

a {
    color: inherit;
    text-decoration: none;
}

/* 焦点环 - 无障碍 */
*:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* 滚动条 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--border-strong);
    border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* 动画关键帧 */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes modalIn {
    from { opacity: 0; transform: translateY(12px) scale(0.98); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

@keyframes toastIn {
    from { opacity: 0; transform: translateY(-8px); }
    to { opacity: 1; transform: translateY(0); }
}

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

/* 无障碍：尊重用户减少动效偏好 */
@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;
    }
}