:root {
    --datalab-color-primary: #2f6df6;
    --datalab-color-primary-hover: #245ce0;
    --datalab-color-text: #111827;
    --datalab-color-text-secondary: #344054;
    --datalab-color-text-muted: #667085;
    --datalab-color-border: #d7deee;
    --datalab-color-error-soft: #fff1f0;
    --datalab-color-error-text: #b42318;
    --datalab-radius-md: 12px;
    --datalab-radius-xl: 24px;
    --datalab-shadow-card: 0 28px 80px rgba(8, 25, 76, 0.24);
    --datalab-font: "Segoe UI", "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    color: var(--datalab-color-text);
    font-family: var(--datalab-font);
    background:
        radial-gradient(circle at 20% 10%, rgba(114, 171, 255, 0.34), transparent 30%),
        radial-gradient(circle at 80% 90%, rgba(25, 91, 222, 0.38), transparent 34%),
        linear-gradient(135deg, #0f2e70 0%, #1d5ed7 48%, #4d8dff 100%);
}

.login-shell {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 28px;
}

.card {
    width: min(460px, 100%);
    background: rgba(255, 255, 255, 0.96);
    border: 1px solid rgba(255, 255, 255, 0.76);
    border-radius: var(--datalab-radius-xl);
    padding: 34px;
    box-shadow: var(--datalab-shadow-card);
}

h1 {
    margin: 0;
    color: var(--datalab-color-text);
    font-size: 30px;
    line-height: 1.2;
}

.intro {
    margin: 12px 0 0;
    color: var(--datalab-color-text-muted);
    line-height: 1.75;
    font-size: 14px;
}

label {
    display: block;
    margin: 18px 0 8px;
    font-size: 14px;
    color: var(--datalab-color-text-secondary);
    font-weight: 700;
}

input {
    width: 100%;
    padding: 13px 14px;
    border-radius: var(--datalab-radius-md);
    border: 1px solid var(--datalab-color-border);
    background: #f8fbff;
    color: var(--datalab-color-text);
    font-size: 15px;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

input:focus {
    border-color: #7da7ff;
    background: #ffffff;
    box-shadow: 0 0 0 4px rgba(47, 109, 246, 0.14);
}

button {
    width: 100%;
    margin-top: 24px;
    padding: 13px 14px;
    border: none;
    border-radius: var(--datalab-radius-md);
    background: linear-gradient(135deg, var(--datalab-color-primary), #6387ff);
    color: white;
    font-size: 15px;
    font-weight: 800;
    cursor: pointer;
    box-shadow: 0 12px 24px rgba(47, 109, 246, 0.28);
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

button:hover {
    transform: translateY(-1px);
    box-shadow: 0 16px 28px rgba(47, 109, 246, 0.32);
    background: linear-gradient(135deg, var(--datalab-color-primary-hover), var(--datalab-color-primary));
}

.hint {
    margin-top: 16px;
    color: var(--datalab-color-text-muted);
    font-size: 13px;
    line-height: 1.7;
}

.notice {
    margin: 18px 0 4px;
    padding: 10px 12px;
    border-radius: var(--datalab-radius-md);
    font-size: 14px;
    line-height: 1.6;
}

.notice-error {
    background: var(--datalab-color-error-soft);
    border: 1px solid #fecdca;
    color: var(--datalab-color-error-text);
}

@media (max-width: 560px) {
    .login-shell {
        padding: 18px;
    }

    .card {
        padding: 26px 22px;
        border-radius: 20px;
    }

    h1 {
        font-size: 26px;
    }
}