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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 460px;
}

.card {
    background: #fff;
    border-radius: 20px;
    padding: 40px 36px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.header {
    text-align: center;
    margin-bottom: 36px;
}

.logo {
    font-size: 56px;
    line-height: 1;
    margin-bottom: 12px;
}

.header h1 {
    font-size: 24px;
    color: #1a1a2e;
    margin-bottom: 8px;
}

.subtitle {
    font-size: 14px;
    color: #888;
}

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

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: #333;
    margin-bottom: 8px;
}

.form-group label .optional {
    font-weight: 400;
    color: #aaa;
    font-size: 12px;
}

.form-group input {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    font-size: 16px;
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
}

.form-group input:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

.btn-primary {
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    border: none;
    border-radius: 12px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s, transform 0.1s;
    margin-top: 8px;
}

.btn-primary:hover:not(:disabled) {
    opacity: 0.92;
}

.btn-primary:active:not(:disabled) {
    transform: scale(0.98);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-loading {
    display: inline-block;
}

.result {
    margin-top: 24px;
    padding: 16px 20px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 15px;
    line-height: 1.5;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateY(-10px); }
    to   { opacity: 1; transform: translateY(0); }
}

.result.success {
    background: #f0fdf4;
    border: 1px solid #bbf7d0;
    color: #15803d;
}

.result.error {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: #dc2626;
}

.result-icon {
    font-size: 24px;
    flex-shrink: 0;
}

.result-text {
    flex: 1;
}

.tips {
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid #f0f0f0;
}

.tips h3 {
    font-size: 14px;
    color: #666;
    margin-bottom: 10px;
}

.tips ul {
    list-style: none;
    padding: 0;
}

.tips li {
    font-size: 13px;
    color: #999;
    line-height: 1.8;
    padding-left: 16px;
    position: relative;
}

.tips li::before {
    content: "·";
    position: absolute;
    left: 4px;
    color: #ccc;
    font-weight: bold;
}

.footer {
    text-align: center;
    margin-top: 24px;
}

.footer p {
    font-size: 12px;
    color: #ccc;
}

@media (max-width: 480px) {
    .card {
        padding: 28px 20px;
    }

    .header h1 {
        font-size: 20px;
    }
}