body {
    /* Use Inter, a clean sans-serif font */
    font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    max-width: 1500px;
    margin: 20px auto;
    padding: 0 20px;
    color: #333;
    background-color: #fdfdfd; /* Slightly off-white background */
}

/* Profile image styling */
img.profile-pic {
    max-width: 180px; /* Slightly smaller */
    height: 180px;
    object-fit: cover;
    border-radius: 50%; /* Circular image */
    float: left;
    margin: 0 30px 20px 0;
    border: 3px solid #eee; /* Light border */
    box-shadow: 0 4px 12px rgba(0,0,0,0.05); /* Soft shadow */
}

/* Clear the float after the image */
.intro-text {
    overflow: hidden; 
}

/* Links */
a {
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}

/* --- STYLES FOR FILTERS --- */
.filter-tabs {
    margin: 30px 0 20px;
    padding: 10px;
    background-color: #f9f9f9;
    border-radius: 8px; /* Rounded corners for the container */
}

.filter-tabs strong {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
}

.filter-btn {
    padding: 8px 16px;
    font-size: 0.95em;
    font-weight: 500;
    border: 1px solid #ccc;
    background-color: #f4f4f4;
    cursor: pointer;
    border-radius: 6px; /* Rounded corners for buttons */
    margin-right: 5px;
    margin-bottom: 5px; /* For mobile wrapping */
    transition: background-color 0.2s, box-shadow 0.2s;
}
.filter-btn:hover {
    background-color: #e0e0e0;
    border-color: #bbb;
}
.filter-btn.active {
    background-color: #004a99;
    color: white;
    border-color: #004a99;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

/* Search Input Styling */
#search-input {
    width: 100%;
    max-width: 600px;
    padding: 10px 15px;
    margin-top: 15px;
    border: 1px solid #ccc;
    border-radius: 6px;
    font-size: 1em;
    box-sizing: border-box; /* Include padding in the element's total width and height */
}
#search-input:focus {
    border-color: #004a99;
    outline: none;
    box-shadow: 0 0 0 3px rgba(0, 74, 153, 0.1); /* Subtle focus ring */
}

/* Class to hide items with a fade effect */
.paper-item.hidden {
    display: none;
}

/* Class to show items */
.paper-item {
    opacity: 1;
    display: block; /* 核心改动：从 list-item 改为 block */
}

/* --- Responsive Design --- */
@media (max-width: 600px) {
    img.profile-pic {
        float: none; /* Stack image on top */
        display: block;
        margin: 0 auto 20px;
        max-width: 150px;
        height: 150px;
    }
    .intro-text {
        overflow: visible; /* Reset clearing */
    }
    h1 {
        font-size: 2em;
        text-align: center;
    }
    h3.subtitle {
        text-align: center;
    }
}