body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f0f2f5;
    color: #333;
    padding: 20px 0;
    box-sizing: border-box;
}

.container {
    background-color: #ffffff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    text-align: center;
    width: 90%;
    max-width: 520px;
    box-sizing: border-box;
}

.logo {
    width: 200px;
    margin-bottom: 20px;
}

h1 {
    margin-top: 0;
    color: #1c1e21;
    font-size: 28px;
}

.author {
    margin: -15px 0 20px 0;
    font-size: 14px;
    color: #606770;
}

#qr-text {
    width: 100%;
    padding: 16px 10px;
    margin-bottom: 20px;
    border: 1px solid #ccd0d5;
    border-radius: 6px;
    font-size: 17px;
    transition: border-color 0.2s, box-shadow 0.2s;
    text-align: center;
    box-sizing: border-box;
}

#qr-text:focus {
    outline: none;
    border-color: #1877f2;
    box-shadow: 0 0 0 2px rgba(24, 119, 242, 0.2);
}

#qr-canvas {
    width: 100%;
    height: auto;
    max-width: 300px;
    border: 1px solid #dddfe2;
    border-radius: 8px;
    margin-bottom: 20px;
}

button {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-top: 10px;
}

#download-png {
    background-color: #1877f2;
    color: white;
}

#download-png:hover {
    background-color: #166fe5;
}

#download-transparent {
    background-color: #6c757d;
    color: white;
}

#download-transparent:hover {
    background-color: #5a6268;
}

#download-jpg {
    background-color: #42b72a;
    color: white;
}

#download-jpg:hover {
    background-color: #36a420;
}

@media (max-width: 600px) {
    .container {
        padding: 20px;
    }

    h1 {
        font-size: 24px;
    }

    .logo {
        width: 150px;
    }

    #qr-text {
        font-size: 16px;
        padding: 14px 10px;
    }
}