:root {
    --bg-color: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --link-border: #e0e0e0;
    --link-hover-bg: #f5f5f5;
    --btn-hover: #eeeeee;
    --avatar-url: url('/static/white_avatar.jpg');
    --font-stack: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-primary: #e0e0e0;
    --text-secondary: #a0a0a0;
    --link-border: #333333;
    --link-hover-bg: #2a2a2a;
    --btn-hover: #333333;
    --avatar-url: url('/static/black_avatar.jpg');
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-stack);
    line-height: 1.6;
    display: flex; justify-content: center; align-items: center;
    min-height: 100vh; padding: 20px;
    transition: background-color 0.4s ease, color 0.4s ease;
}

.container {
    width: 100%; max-width: 580px;
    animation: fadeIn 0.8s ease-out;
}

/* --- 按钮与图标核心样式 (修改部分) --- */

.theme-toggle-btn {
    position: fixed; top: 20px; right: 20px;
    width: 40px; height: 40px;
    background: transparent; border: none;
    cursor: pointer; border-radius: 50%;
    color: var(--text-primary);
    /* 关键：设置为相对定位，为了让里面的图标绝对定位 */
    position: fixed; 
    display: flex; align-items: center; justify-content: center;
    transition: background-color 0.2s;
    overflow: hidden; /* 防止动画溢出 */
}

.theme-toggle-btn:hover { background-color: var(--btn-hover); }

/* 图标通用样式：绝对居中 */
.theme-toggle-btn .icon {
    position: absolute;
    top: 50%; left: 50%;
    /* 强制居中，不再依赖外部边距 */
    transform: translate(-50%, -50%); 
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 默认（浅色模式）状态 */
.icon-sun { opacity: 1; transform: translate(-50%, -50%) rotate(0deg) scale(1); }
.icon-moon { opacity: 0; transform: translate(-50%, -50%) rotate(90deg) scale(0.5); }

/* 深色模式状态 */
[data-theme="dark"] .icon-sun { opacity: 0; transform: translate(-50%, -50%) rotate(-90deg) scale(0.5); }
[data-theme="dark"] .icon-moon { opacity: 1; transform: translate(-50%, -50%) rotate(0deg) scale(1); }

/* --- 页面其余样式 --- */

header { margin-bottom: 3rem; }
.avatar {
    width: 100px; height: 100px; border-radius: 50%; margin-bottom: 1.5rem;
    background-image: var(--avatar-url);
    background-size: cover; background-position: center;
    background-color: var(--link-hover-bg);
    transition: all 0.4s ease;
}
h1 { font-size: 1.8rem; font-weight: 600; margin-bottom: 0.5rem; letter-spacing: -0.5px; }
.bio { color: var(--text-secondary); font-size: 1rem; }
.links { display: flex; flex-direction: column; gap: 12px; }
.link-item {
    display: flex; justify-content: space-between; align-items: center;
    padding: 12px 16px; border: 1px solid var(--link-border);
    border-radius: 6px; text-decoration: none; color: var(--text-primary);
    font-size: 0.95rem; transition: all 0.2s ease;
}
.link-item:hover {
    background-color: var(--link-hover-bg); border-color: var(--text-secondary);
    transform: translateY(-1px);
}
.link-desc { font-size: 0.85rem; color: var(--text-secondary); }
footer { margin-top: 4rem; border-top: 1px solid var(--link-border); padding-top: 1.5rem; font-size: 0.8rem; color: var(--text-secondary); }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}