* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "PingFang SC", "Microsoft Yahei", sans-serif;
    scroll-behavior: smooth;
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

:root {
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 30px;
    --transition: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

.banner {
    width: 100%;
    height: 100vh;
    padding-top: 80px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--gradient-light);
    position: relative;
    overflow: hidden;
    text-align: center;
}

.banner::before {
    content: '';
    position: absolute;
    width: 600px;
    height: 600px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(128, 128, 128, 0.08) 0%, transparent 70%);
    top: -200px;
    right: -200px;
}

.banner::after {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(128, 128, 128, 0.05) 0%, transparent 70%);
    bottom: -150px;
    left: -150px;
}

.banner>* {
    position: relative;
    z-index: 2;
}

.banner-top-tag {
    margin-bottom: 20px;
}

.banner h1 {
    font-size: 86px;
    font-weight: 900;
    letter-spacing: 18px;
    margin-bottom: 24px;
    background: linear-gradient(135deg, var(--text-main) 0%, var(--text-gray) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.banner p {
    font-size: 20px;
    color: var(--text-gray);
    letter-spacing: 2px;
    margin-bottom: 48px;
}

.banner-btn {
    padding: 14px 46px;
    background: var(--text-main);
    color: var(--white);
    text-decoration: none;
    border-radius: var(--radius-lg);
    font-size: 16px;
    transition: var(--transition);
    box-shadow: var(--shadow-soft);
}

.banner-btn:hover {
    opacity: 0.85;
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

.error-code {
    display: inline-block;
    cursor: pointer;
    transition: transform 0.2s ease;
    padding: 0 2px;
}

.error-code:hover {
    transform: scale(1.06);
}

.copy-tip {
    position: fixed;
    top: 100px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-main);
    color: var(--white);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
    z-index: 9999;
}

.copy-tip.show {
    opacity: 1;
}

@media (max-width:768px) {
    .banner h1 {
        font-size: 40px;
        letter-spacing: 6px;
    }
    .banner p {
        font-size: 16px;
    }
}