/* ============================================================
   base.css — 全局基础
   浏览器样式重置、夜间屋底光池与通用工具类
   ============================================================ */

/* 清除默认边距并统一盒模型 */
*,
*::before,
*::after {
    box-sizing: border-box;

    margin: 0;

    padding: 0;

}

/* 夜间屋底：暖光光池叠加在深咖底色上 */
html {
    background-color: var(--color-bg);

    background-image:
        radial-gradient(1100px 700px at 72% -8%, rgba(232, 133, 58, 0.16), transparent 62%),
        radial-gradient(900px 640px at 6% 108%, rgba(240, 180, 92, 0.1), transparent 60%),
        linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-deep) 100%);

    background-attachment: fixed;

    color: var(--color-ink);

    font-family: var(--font-body);

    line-height: 1.75;

    scroll-behavior: smooth;

}

/* 全页渐晕：四周压暗聚拢视线，如夜里的屋子 */
body::after {
    content: "";

    position: fixed;

    inset: 0;

    z-index: 1;

    pointer-events: none;

    background: radial-gradient(120% 90% at 50% 42%, transparent 58%, rgba(10, 5, 2, 0.5) 100%);

}

/* 墙面颗粒肌理：细噪声叠在夜色底上 */
html::before {
    content: "";

    position: fixed;

    inset: 0;

    z-index: 0;

    pointer-events: none;

    background-image: url("data:image/svg+xml;base64,PHN2ZyB4bWxucz0naHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmcnIHdpZHRoPScxODAnIGhlaWdodD0nMTgwJz48ZmlsdGVyIGlkPSduJz48ZmVUdXJidWxlbmNlIHR5cGU9J2ZyYWN0YWxOb2lzZScgYmFzZUZyZXF1ZW5jeT0nMC44NScgbnVtT2N0YXZlcz0nMicgc2VlZD0nNScvPjxmZUNvbG9yTWF0cml4IHZhbHVlcz0nMCAwIDAgMCAwLjkgMCAwIDAgMCAwLjc1IDAgMCAwIDAgMC41NSAwIDAgMCAwLjA1IDAnLz48L2ZpbHRlcj48cmVjdCB3aWR0aD0nMTgwJyBoZWlnaHQ9JzE4MCcgZmlsdGVyPSd1cmwoI24pJy8+PC9zdmc+");

}

/* 暖色滚动条：轨道深咖、把手原木 */
::-webkit-scrollbar {
    width: 12px;

}

/* 滚动条轨道 */
::-webkit-scrollbar-track {
    background: var(--color-bg-deep);

}

/* 滚动条把手 */
::-webkit-scrollbar-thumb {
    background: #4a3320;

    border-radius: 6px;

    border: 2px solid var(--color-bg-deep);

}

/* 把手悬停提亮 */
::-webkit-scrollbar-thumb:hover {
    background: #5f432a;

}

/* 标题统一使用衬线字族 */
h1,
h2,
h3 {
    font-family: var(--font-display);

    font-weight: 700;

    line-height: 1.3;

}

/* 链接默认继承墨字色并去掉下划线 */
a {
    color: inherit;

    text-decoration: none;

}

/* 列表去除项目符号与缩进 */
ul,
ol {
    list-style: none;

}

/* 图片与矢量图保持块级弹性缩放 */
img,
svg {
    display: block;

    max-width: 100%;

}

/* 文本选中态：琥珀底配深咖字 */
::selection {
    background-color: var(--color-amber);

    color: var(--color-bg-deep);

}

/* 键盘跳转正文的捷径链接，仅在聚焦时显形 */
.skip-link {
    position: absolute;

    left: 16px;

    top: -64px;

    z-index: 99;

    padding: 10px 18px;

    background-color: var(--color-flame);

    border-radius: var(--radius-chip);

    color: #24150a;

    transition: top 0.2s ease;

}

/* 跳转链接聚焦时滑入视口 */
.skip-link:focus {
    top: 16px;

}

/* 屏幕阅读器专用文本 */
.visually-hidden {
    position: absolute;

    width: 1px;

    height: 1px;

    overflow: hidden;

    clip: rect(0 0 0 0);

    white-space: nowrap;

}