/* --- 1. M3 Expressive 色彩与字体系统 --- */
:root {
    color-scheme: light dark;
    --motion-easing: cubic-bezier(0.4, 0, 0.2, 1);
    --motion-duration: 0.3s;
    --font-display: 'Plus Jakarta Sans', sans-serif;
    --font-body: 'Inter', sans-serif;
}

/* 深色主题变量 */
:root[data-theme="dark"] {
    --primary: #D0BCFF; 
    --on-primary: #381E72;
    --primary-container: #4F378B;
    --on-primary-container: #EADDFF;
    --surface-container: #211F26; 
    --surface-bright: #36343B; 
    --surface-dim: #141218;
    --surface-container-highest: #3D3B42; 
    --on-surface: #E6E1E5;
    --on-surface-variant: #CAC4D0; 
    --outline: #938F99;
    --scrim: #000000;
    --shadow-color: rgba(0, 0, 0, 0.4);
}

/* 浅色主题变量 */
:root[data-theme="light"] {
    --primary: #6750A4;
    --on-primary: #FFFFFF;
    --primary-container: #EADDFF;
    --on-primary-container: #21005D;
    --surface-container: #F3EDF7;
    --surface-bright: #FEF7FF;
    --surface-dim: #DED8E1;
    --surface-container-highest: #E6E0E9;
    --on-surface: #1C1B1F;
    --on-surface-variant: #49454F;
    --outline: #79747E;
    --scrim: #000000;
    --shadow-color: rgba(0, 0, 0, 0.2);
}

/* --- 2. 基础布局与动效 --- */
body {
    font-family: var(--font-body);
    background-color: var(--surface-bright); /* 使用更亮的背景 */
    color: var(--on-surface);
    margin: 0;
    padding: 2rem;
    box-sizing: border-box;
    display: flex;
    justify-content: center;
    transition: background-color var(--motion-duration) ease, color var(--motion-duration) ease;
}

.main-container {
    width: 100%;
    max-width: 900px;
    padding-top: 5vh; /* 增加顶部空间 */
}

/* --- 3. Header & 开关 --- */
.portal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1.5rem; 
    flex-wrap: nowrap; 
    margin-bottom: 5rem;
}
.header-content { display: flex; align-items: center; gap: 1.5rem;min-width: 0; }
.header-avatar { width: 80px; height: 80px; }
.header-text h1 {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 2.75rem); /* 响应式字体 */
    font-weight: 700;
    margin: 0;
}
.header-text .subtitle {
    font-size: clamp(1rem, 2.5vw, 1.1rem);
    color: var(--on-surface-variant);
    margin: 0.25rem 0 0;
}

/* 1. 总容器 (label.theme-switch) */
/* 它的作用是定义一个固定的、可供鼠标悬停的区域 */
.theme-switch {
    position: relative;
    display: block; /* 使用 block 或 inline-block */
    width: 60px;  /* 固定的、展开后的宽度 */
    height: 34px;
    cursor: pointer;
    transition: none; 
}

.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

/* 2. 背景轨道 (.slider-track) */
/* 这个元素专门负责实现“展开”和“收缩”的动画 */
.slider-track {
    position: absolute;
    top: 0;
    left: 0;
    width: 34px; /* 默认是收缩状态，和圆点一样大 */
    height: 34px;
    background-color: var(--surface-container-highest);
    border-radius: 17px; /* 收缩时是圆形 */
                
    box-shadow: inset 2px 2px 4px rgba(0,0,0,0.2), 
                    inset -2px -2px 4px rgba(255,255,255,0.05);

    transition: width 0.3s ease, left 0.3s ease, border-radius 0.3s ease, box-shadow 0.3s ease;
}

/* ★ 鼠标悬停时，轨道展开 */
.theme-switch:hover .slider-track {
    width: 60px; /* 展开为长条形 */
}

/* ★ 当开关被选中(夜间模式)且鼠标未悬停时，收缩的轨道移动到右边 */
.theme-switch input:checked + .slider-track {
    left: 26px; /* 60px - 34px = 26px，移动到最右侧 */
}
/* 鼠标悬停在已选中的开关上时，轨道也要保持在左侧展开 */
.theme-switch:hover input:checked + .slider-track {
    left: 0;
}


/* 3. 滑块圆点 (.slider-dot) */
/* 这个元素只负责左右平移，动画路径单一且稳定 */
.slider-dot {
    position: absolute;
    height: 26px;
    width: 26px;
    left: 4px; /* 初始内边距 */
    top: 4px;
    background-color: var(--md-sys-color-primary);
    border-radius: 50%;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;

    box-shadow: 0 4px 8px rgba(0,0,0,0.3);

    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), background-color 0.3s ease, box-shadow 0.3s ease;

}

/* ★ 当开关被选中(夜间模式)时，圆点向右移动 */
.theme-switch input:checked ~ .slider-dot {
    transform: translateX(26px); /* 移动固定的26px */
    background-color: var(--primary-container);
}


/* 4. 图标样式 */
.slider-dot .icon {
    position: absolute;
    width: 20px;
    height: 20px;
    color: var(--md-sys-color-on-primary);
    transition: opacity 0.3s ease, transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);

    display: flex;
    align-items: center;      /* 垂直居中 */
    justify-content: center;  

}

.sun {
    opacity: 1;
    transform: translateY(0) rotate(0deg);
}
.moon {
    opacity: 0;
    transform: translateY(20px) rotate(-45deg); /* 从下方进入 */
}

input:checked ~ .slider-dot .sun {
    opacity: 0;
    transform: translateY(-20px) rotate(45deg); /* 向上方退出 */
}
input:checked ~ .slider-dot .moon {
    opacity: 1;
    transform: translateY(0) rotate(0deg);
    color: var(--md-sys-color-on-surface);
}

/* --- 4. 终极版 Expressive 卡片 --- */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.card {
    text-decoration: none;
    background-color: var(--surface-container);
    border: 1px solid var(--outline);
    border-radius: 28px; /* 更大的圆角 */
    padding: 1.5rem;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 8px var(--shadow-color);
    transition: transform var(--motion-duration) var(--motion-easing), 
                box-shadow var(--motion-duration) var(--motion-easing),
                border-color var(--motion-duration) ease;
}

.card:hover {
    transform: translateY(-8px);
    border-color: var(--primary);
    box-shadow: 0 12px 24px var(--shadow-color);
}
.card:active {
    transform: translateY(-2px) scale(0.98);
    box-shadow: 0 4px 8px var(--shadow-color);
}

.card-content {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    z-index: 2;
    position: relative;
}

.card-icon {
    font-family: 'Material Symbols Outlined';
    font-size: 36px;
    color: var(--card-color);
    flex-shrink: 0;
    transition: transform var(--motion-duration) var(--motion-easing);
}
.card:hover .card-icon {
    transform: scale(1.2) rotate(-10deg);
}

.card-text h2 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--on-surface);
    margin: 0 0 0.25rem;
}
.card-text p {
    font-size: 1rem;
    color: var(--on-surface-variant);
    margin: 0;
    line-height: 1.5;
}

/* 卡片后的装饰性渐变，增加表现力 */
.card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, hsla(0, 0%, 100%, 0.1), hsla(0, 0%, 100%, 0) 60%);
    opacity: 0;
    transform: scale(0);
    transition: opacity 0.5s var(--motion-easing), transform 0.5s var(--motion-easing);
    z-index: 1;
}

:root[data-theme="dark"] .card::before {
     background: radial-gradient(circle, rgba(208, 188, 255, 0.1), rgba(208, 188, 255, 0) 60%);
}


.card:hover::before {
    opacity: 1;
    transform: scale(1);
}

/* --- 5. Footer --- */
.portal-footer {
    text-align: center;
    margin-top: 6rem;
    padding-bottom: 2rem;
    color: var(--on-surface-variant);
    opacity: 0.7;
}