.container {
    background-color: #ffffff;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 400px;
    margin: 10px auto;
    text-align: center;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

#invitefriends {
    color: #333;
    font-size: 1.8em;
    margin: 0 0 15px;
}

.promo-text {
    font-size: 1em;
    color: #666;
    margin: 0 0 20px;
    line-height: 1.4;
}

.sub-title {
    font-size: 1.2em;
    color: #333;
    margin: 0 0 8px;
}

.commission {
    font-size: 1.8em;
    color: #007bff;
    margin: 0 0 20px;
    font-weight: bold;
}

.invite-link-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: #f8f9fa;
    padding: 10px;
    border-radius: 8px;
    margin: 0 0 20px;
}

.invite-link {
    font-size: 0.9em;
    color: #555;
    word-break: break-all;
    text-align: left;
    flex: 1;
    padding-right: 10px;
}

.copy-btn {
    background-color: #007bff;
    border: none;
    border-radius: 6px;
    padding: 0;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background-color 0.2s;
}

.copy-btn:hover {
    background-color: #0056b3;
}

.copy-icon {
    font-size: 0; /* 隐藏文字，用图标 */
    display: inline-block;
    width: 20px;
    height: 20px;
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="white"><path d="M16 1H4a2 2 0 0 0-2 2v14h2V3h12V1zm3 4H8a2 2 0 0 0-2 2v14c0 1.1.9 2 2 2h11a2 2 0 0 0 2-2V7a2 2 0 0 0-2-2zm0 16H8V7h11v14z"/></svg>');
    background-size: cover;
}

.button-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.btn {
    padding: 12px;
    font-size: 1em;
    color: #fff;
    background-color: #007bff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
    width: 100%;
    box-sizing: border-box;
}

.btn:hover {
    background-color: #0056b3;
}

/* 针对超小屏幕微调 */
@media (max-width: 360px) {
    .container {
        padding: 15px;
        margin: 5px auto;
    }

    #invitefriends {
        font-size: 1.6em;
    }

    .commission {
        font-size: 1.6em;
    }

    .invite-link {
        font-size: 0.85em;
    }
}