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

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #fff;
    color: #333;
    line-height: 1.6;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 15px;
}

header {
    background: linear-gradient(to right, #e9f2fe, #fafcff);
    padding: 30px 0;
    margin-bottom: 30px;
    border-radius: 10px;
    position: relative;
}

.back-link {
    position: absolute;
    top: 30px;
    left: 20px;
    display: inline-flex;
    align-items: center;
    padding: 10px 20px;
    background: linear-gradient(135deg, #4da9ff 0%, #1a8cff 100%);
    color: #fff;
    text-decoration: none;
    border-radius: 25px;
    font-size: 15px;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(26, 140, 255, 0.3);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    letter-spacing: 0.5px;
}

.back-link:hover {
    background: linear-gradient(135deg, #5cb8ff 0%, #2999ff 100%);
    transform: translateX(-5px) translateY(-2px);
    box-shadow: 0 6px 16px rgba(26, 140, 255, 0.4);
}

.back-link::before {
    content: "←";
    margin-right: 8px;
    font-size: 18px;
    font-weight: 700;
    transition: transform 0.3s ease;
}

.back-link:hover::before {
    transform: translateX(-3px);
}

h1 {
    color: #2a4e9a;
    text-align: center;
    font-size: 28px;
    margin-bottom: 10px;
}

.update-time {
    text-align: center;
    color: #666;
    font-size: 14px;
}

.nav-tags {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin: 30px 0;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 8px;
}

.nav-tag {
    display: inline-block;
    padding: 8px 16px;
    background: linear-gradient(to right, #4da9ff, #1a8cff);
    color: #fff;
    text-decoration: none;
    border-radius: 20px;
    font-size: 14px;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(77, 169, 255, 0.3);
}

.nav-tag:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(77, 169, 255, 0.4);
}

.section {
    margin-bottom: 40px;
    padding: 25px;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

.section h2 {
    color: #2a4e9a;
    font-size: 24px;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #e9f2fe;
}

.highlight {
    background-color: #e8f4ff;
    border-left: 4px solid #4da9ff;
    padding: 15px;
    margin: 15px 0;
    border-radius: 0 4px 4px 0;
}

.paper {
    margin: 25px 0;
    padding: 20px;
    background: #fafbfc;
    border-radius: 6px;
    border-left: 3px solid #4da9ff;
}

.paper h3 {
    color: #333;
    font-size: 18px;
    margin-bottom: 12px;
}

.paper-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 12px;
    font-size: 14px;
}

.paper-meta span {
    display: inline-flex;
    align-items: center;
}

.score {
    background: linear-gradient(to right, #4da9ff, #1a8cff);
    color: #fff;
    padding: 2px 8px;
    border-radius: 10px;
    font-weight: bold;
}

.paper-link {
    color: #1a8cff;
    text-decoration: none;
}

.paper-link:hover {
    text-decoration: underline;
}

.paper-abstract {
    color: #555;
    font-size: 15px;
    line-height: 1.8;
}

.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: linear-gradient(to right, #4da9ff, #1a8cff);
    color: #fff;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
    transition: all 0.3s ease;
    opacity: 0;
    visibility: hidden;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

footer {
    margin-top: 40px;
    padding: 20px 0;
    border-top: 1px solid #eee;
    text-align: center;
    color: #666;
    font-size: 14px;
}

@media screen and (max-width: 768px) {
    body {
        padding: 10px;
    }

    h1 {
        font-size: 24px;
    }

    .nav-tags {
        padding: 15px;
    }

    .nav-tag {
        padding: 6px 12px;
        font-size: 13px;
    }

    .section {
        padding: 15px;
    }

    .paper {
        padding: 15px;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
    }
}