#dtmf-generator {
    max-width: 1100px;
    margin: 25px auto;
    padding: 25px;
    background: #f7f7f7;
    border: 1px solid #d4d4d4;
    border-radius: 8px;
    font-family: Arial, sans-serif;
    color: #222;
}

#dtmf-generator * {
    box-sizing: border-box;
}

#dtmf-generator .dtmf-header {
    text-align: center;
    margin-bottom: 25px;
}

#dtmf-generator .dtmf-header h2 {
    font-size: 28px;
    font-weight: 700;
}

#dtmf-generator .dtmf-panel {
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 22px;
    height: 100%;
}

#dtmf-generator .dtmf-display {
    background: #101010;
    color: #00ff9c;
    border-radius: 8px;
    padding: 18px;
    text-align: center;
    margin-bottom: 20px;
}

#dtmf-generator .dtmf-current-key {
    font-size: 42px;
    font-weight: bold;
}

#dtmf-generator .dtmf-frequency {
    color: #aaa;
    font-size: 14px;
}

#dtmf-generator .dtmf-keypad {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

#dtmf-generator .dtmf-key {
    border: 1px solid #444;
    border-radius: 7px;
    background: linear-gradient(145deg, #333, #000);
    color: #fff;
    font-size: 24px;
    font-weight: 700;
    min-height: 75px;
    cursor: pointer;
    transition: 0.15s;
}

#dtmf-generator .dtmf-key:hover {
    background: linear-gradient(145deg, #555, #111);
    transform: translateY(-2px);
}

#dtmf-generator .dtmf-key.active {
    border-color: #00ff9c;
    color: #00ff9c;
}

#dtmf-generator .dtmf-key small {
    display: block;
    font-size: 10px;
    color: #bbb;
    font-weight: 400;
    margin-top: 3px;
}

#dtmf-generator .dtmf-control-btn {
    border: none;
    color: #fff;
    background: linear-gradient(145deg, #333, #000);
    border-radius: 6px;
    padding: 10px 18px;
    font-weight: 600;
    cursor: pointer;
}

#dtmf-generator .dtmf-control-btn:hover {
    background: linear-gradient(145deg, #555, #111);
    color: #fff;
}

#dtmf-generator .dtmf-stop-btn {
    background: linear-gradient(145deg, #c62828, #7f0000);
}

#dtmf-generator .dtmf-stop-btn:hover {
    background: linear-gradient(145deg, #e53935, #900000);
}

#dtmf-generator .dtmf-output {
    min-height: 100px;
    font-family: monospace;
    font-size: 18px;
    letter-spacing: 2px;
    word-break: break-all;
}

#dtmf-generator .dtmf-table {
    font-size: 13px;
}

#dtmf-generator .dtmf-table th {
    background: #222;
    color: #fff;
}

#dtmf-generator .dtmf-table td {
    text-align: center;
}

#dtmf-generator .form-label {
    font-weight: 600;
}

#dtmf-generator .dtmf-status {
    font-size: 13px;
    color: #666;
    margin-top: 12px;
}

@media(max-width: 576px) {
    #dtmf-generator {
        padding: 12px;
    }

    #dtmf-generator .dtmf-panel {
        padding: 14px;
    }

    #dtmf-generator .dtmf-key {
        min-height: 60px;
        font-size: 20px;
    }

    #dtmf-generator .dtmf-header h2 {
        font-size: 23px;
    }

    #dtmf-generator .dtmf-control-btn {
        padding: 9px 12px;
    }
}