body {
    font-family: 'Inter', sans-serif;
    background-color: #f4f6f8;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: #333;
}

.container {
    width: 100%;
    max-width: 480px;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 40px;
}

.logo {
    font-size: 24px;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 10px;
}

nav a {
    color: #666;
    text-decoration: none;
    margin: 0 10px;
    font-size: 14px;
}

.card {
    background: white;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
    text-align: center;
}

h1 { font-size: 22px; margin-bottom: 10px; }
.subtitle { color: #666; font-size: 14px; margin-bottom: 30px; }

.form-group { text-align: left; margin-bottom: 20px; }
label { display: block; font-size: 12px; font-weight: 600; margin-bottom: 8px; color: #555; }
input {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 16px;
    box-sizing: border-box; /* 关键：防止输入框溢出 */
}

button {
    width: 100%;
    padding: 14px;
    background-color: #0070f3;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}
button:hover { background-color: #005bb5; }
button:disabled { background-color: #ccc; cursor: not-allowed; }

.status { margin-bottom: 20px; font-size: 14px; padding: 10px; border-radius: 6px; }
.status.processing { background-color: #e3f2fd; color: #0d47a1; }
.status.error { background-color: #ffebee; color: #c62828; }
.hidden { display: none; }

.success-box {
    background: #e8f5e9;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    border: 1px solid #c8e6c9;
}
.redeem-btn {
    display: inline-block;
    margin-top: 10px;
    text-decoration: none;
    background: #2e7d32;
    color: white;
    padding: 10px 20px;
    border-radius: 4px;
    font-weight: 600;
}

footer { text-align: center; margin-top: 40px; color: #999; font-size: 12px; }