/* ========== 基础重置 ========== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Icons", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    -webkit-tap-highlight-color: transparent;
}

html {
    height: 100%;
    scroll-behavior: smooth;
    color-scheme: dark;
}
html.light-mode {
    color-scheme: light;
}

body {
    min-height: 100vh;
    min-height: 100dvh;
    background: var(--bg-gradient) fixed;
    color: var(--text-main);
    display: flex;
    overflow-x: hidden;
    -webkit-overflow-scrolling: touch;
    /* 防止 iOS 橡皮筋把固定按钮带偏 */
    overscroll-behavior-x: none;
    overscroll-behavior-y: contain;
    position: relative;
}
/* 无壁纸时：遮罩暗化压暗背景渐变（有壁纸时由 body.has-wallpaper 渐变承担） */
body:not(.has-wallpaper)::before {
    content: '';
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    background: rgba(0, 0, 0, var(--wallpaper-mask-opacity, 0.10));
}
button,
a.card,
.tab-item,
.engine-btn,
.settings-tab-btn {
    touch-action: manipulation;
}

/* 减少动画时的重绘开销 */
@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;
    }
}

::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-normal); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-sub); }