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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    color: #1f2933;
    /* 仿支付宝登录风格：顶部清爽、底部饱满的蓝色渐变背景 */
    background:
            radial-gradient(circle at 10% 0%, rgba(255, 255, 255, 0.9) 0%, rgba(255, 255, 255, 0) 45%),
            linear-gradient(145deg, #e6f4ff 0%, #b3ddff 28%, #4b9dff 65%, #0366d6 100%);
    min-height: 100vh;
}

.page-bg {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px 16px;
    padding-bottom: 60px; /* 为底部备案信息预留空间 */
}

.container {
    width: 100%;
    max-width: 960px;
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    gap: 40px;
    align-items: center;
}

/* 品牌区域 */
.brand-area {
    color: #e5edff;
}

.brand-logo {
    width: 56px;
    height: 56px;
    border-radius: 18px;
    background: rgba(15, 23, 42, 0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    margin-bottom: 16px;
    box-shadow: 0 20px 45px rgba(15, 23, 42, 0.4);
}

.brand-title {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: 0.03em;
    margin-bottom: 8px;
    /* 提高在浅色背景上的可读性 */
    color: #0b3768;
    text-shadow: 0 2px 6px rgba(15, 23, 42, 0.5);
}

.brand-subtitle {
    font-size: 14px;
    opacity: 0.96;
    line-height: 1.6;
    color: #123a6c;
    text-shadow: 0 1px 3px rgba(15, 23, 42, 0.5);
}

/* 登录卡片 */
.card {
    background: rgba(255, 255, 255, 0.96);
    border-radius: 18px;
    padding: 28px 26px 24px;
    box-shadow:
            0 18px 45px rgba(15, 23, 42, 0.30),
            0 0 0 1px rgba(148, 163, 184, 0.20);
    backdrop-filter: blur(22px);
}

.card-title {
    font-size: 22px;
    font-weight: 600;
    color: #0f172a;
    margin-bottom: 8px;
}

.card-desc {
    font-size: 13px;
    color: #6b7280;
    margin-bottom: 18px;
}

.input-group {
    margin-bottom: 16px;
}

.input-group label {
    display: block;
    margin-bottom: 6px;
    font-size: 13px;
    color: #4b5563;
}

input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 10px 11px;
    border-radius: 10px;
    border: 1px solid #d1d5db;
    font-size: 14px;
    transition: border-color 0.18s ease, box-shadow 0.18s ease, background-color 0.18s ease;
    background-color: #f9fafb;
    outline: none;
}

input[type="text"]::placeholder,
input[type="password"]::placeholder {
    color: #9ca3af;
}

input[type="text"]:focus,
input[type="password"]:focus {
    border-color: #4f46e5;
    box-shadow: 0 0 0 1px rgba(79, 70, 229, 0.2), 0 10px 25px rgba(15, 23, 42, 0.18);
    background-color: #ffffff;
}

.form-extra {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 18px;
    font-size: 13px;
}

.checkbox {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
    color: #4b5563;
}

.checkbox input[type="checkbox"] {
    width: 14px;
    height: 14px;
    border-radius: 4px;
    border: 1px solid #d1d5db;
}

.btn-primary {
    width: 100%;
    padding: 10px;
    background: linear-gradient(135deg, #4f46e5, #6366f1);
    color: #ffffff;
    border: none;
    border-radius: 999px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 16px 30px rgba(79, 70, 229, 0.45);
    transition: transform 0.15s ease, box-shadow 0.15s ease, filter 0.15s ease;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 22px 40px rgba(79, 70, 229, 0.55);
    filter: brightness(1.03);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 12px 25px rgba(79, 70, 229, 0.45);
}

.footer {
    margin-top: 18px;
    text-align: center;
    font-size: 13px;
    color: #6b7280;
}

.footer-text {
    margin-right: 4px;
}

.link-primary,
.link-small {
    color: #4f46e5;
    text-decoration: none;
    font-weight: 500;
}

.link-small {
    font-size: 12px;
}

.link-primary:hover,
.link-small:hover {
    text-decoration: underline;
}

/* 响应式处理：窄屏下上下排布 */
@media (max-width: 768px) {
    .page-bg {
        padding: 16px 12px 56px; /* 移动端增加底部留白，避免备案信息被遮挡 */
    }

    .container {
        grid-template-columns: minmax(0, 1fr);
        gap: 24px;
    }

    .brand-area {
        text-align: center;
    }

    .brand-logo {
        margin: 0 auto 12px;
    }
}