:root {
    --primary-color: #5CACEE;
    --primary-dark: #2a4e9a;
    --text-dark: #2a4e9a;
    --text-medium: #5a6b9c;
    --bg-light: #f8faff;
    --card-bg: white;
    --box-shadow: 0 8px 25px rgba(70, 110, 180, 0.12);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

body {
    background: linear-gradient(135deg, #f0f5ff, #e4ecff);
    color: #333;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.login-container {
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: var(--box-shadow);
    padding: 30px;
    width: 100%;
    max-width: 400px;
    text-align: center;
}

.logo {
    font-size: 28px;
    color: var(--primary-dark);
    font-weight: 700;
    margin-bottom: 25px;
}

h2 {
    color: var(--text-dark);
    margin-bottom: 25px;
}

.form-group {
    margin-bottom: 20px;
    text-align: left;
}

label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-medium);
    font-weight: 500;
}

input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid #dce1e9;
    border-radius: 8px;
    font-size: 16px;
    transition: all 0.3s;
}

input[type="text"]:focus,
input[type="password"]:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(92, 172, 238, 0.2);
    outline: none;
}

.btn {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    width: 100%;
    transition: var(--transition);
}

.btn:hover {
    background: linear-gradient(135deg, #4a9fe3, #1d3e7a);
    transform: translateY(-2px);
}

.error {
    color: #FF6B6B;
    margin-top: 15px;
}

.copyright {
    margin-top: 25px;
    color: var(--text-medium);
    font-size: 14px;
}