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

body {
    min-height: 100vh;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-color: #1a1a2e;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    position: relative;
}

/* 浅色字主题：适合深色/偏暗背景图 */
body.theme-light {
    --text-color: cornsilk;
    --text-shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
    --nav-border: rgba(255, 255, 255, 0.4);
    --nav-bg: rgba(0, 0, 0, 0.2);
    --nav-bg-hover: rgba(0, 0, 0, 0.4);
}

/* 深色字主题：适合浅色/偏亮背景图 */
body.theme-dark {
    --text-color: #1a1a2e;
    --text-shadow: 0 2px 8px rgba(255, 255, 255, 0.6);
    --nav-border: rgba(26, 26, 46, 0.35);
    --nav-bg: rgba(255, 255, 255, 0.45);
    --nav-bg-hover: rgba(255, 255, 255, 0.65);
}

.bg-overlay {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
}

.overlay-light {
    background: rgba(255, 255, 255, 0.25);
}

.overlay-medium {
    background: rgba(0, 0, 0, 0.25);
}

.overlay-dark {
    background: rgba(0, 0, 0, 0.45);
}

.page-content {
    position: relative;
    z-index: 1;
    min-height: 100vh;
}

.site-title {
    text-align: center;
    color: var(--text-color);
    position: absolute;
    top: 10%;
    left: 50%;
    transform: translateX(-50%);
    font-size: 2rem;
    text-shadow: var(--text-shadow);
}

.site-nav {
    position: absolute;
    top: 20%;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 2rem;
}

.site-nav a {
    color: var(--text-color);
    text-decoration: none;
    font-size: 1.1rem;
    padding: 0.5rem 1.5rem;
    border: 1px solid var(--nav-border);
    border-radius: 8px;
    backdrop-filter: blur(4px);
    background: var(--nav-bg);
    text-shadow: var(--text-shadow);
    transition: background 0.2s;
}

.site-nav a:hover {
    background: var(--nav-bg-hover);
}

.icp-footer {
    position: absolute;
    bottom: 0;
    width: 100%;
    text-align: center;
    padding: 1rem;
    color: var(--text-color);
    text-shadow: var(--text-shadow);
}

.icp-footer a {
    color: var(--text-color);
    text-decoration: none;
}

.icp-footer a:hover {
    text-decoration: underline;
}