.tone-generator {
    max-width: 1100px;
    margin: 30px auto;
    padding: 25px;
    background: #fff;
    border: 1px solid #e5e5e5;
    border-radius: 12px;
    box-shadow: 0 5px 25px rgba(0,0,0,.06);
    font-family: Arial,sans-serif;
}

.tone-title {
    font-size: 27px;
    font-weight: 700;
    color: #171717;
}

.tone-subtitle { color: #777; font-size: 14px; }

.tone-panel {
    background: #f8f8f8;
    border: 1px solid #e8e8e8;
    border-radius: 10px;
    padding: 22px;
    height: 100%;
}

.frequency-box {
    text-align: center;
    background: #fff;
    border: 1px solid #e5e5e5;
    border-radius: 9px;
    padding: 16px;
}

.frequency-value {
    font-size: 43px;
    font-weight: 700;
    color: #171717;
}

.frequency-value span {
    font-size: 18px;
    color: #777;
}

.note-label { color: #777; font-size: 13px; }

.section-label {
    font-size: 14px;
    font-weight: 700;
    color: #333;
    margin-bottom: 11px;
}

.wave-buttons {
    display: grid;
    grid-template-columns: repeat(2,1fr);
    gap: 10px;
}

.wave-btn {
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 7px;
    padding: 13px 8px;
    font-size: 14px;
    font-weight: 600;
    color: #333;
    cursor: pointer;
    transition: .2s;
}

.wave-btn:hover {
    border-color: #555;
}

.wave-btn.active {
    background: linear-gradient(135deg,#333,#000);
    color: #fff;
    border-color: #000;
}

.volume-value {
    font-size: 16px;
    font-weight: 700;
}

.form-range {
    accent-color: #111;
}

.form-range::-webkit-slider-thumb {
    background: #111;
}

.form-range::-moz-range-thumb {
    background: #111;
}

.volume-labels {
    display: flex;
    justify-content: space-between;
    font-size: 12px;
    color: #888;
}

.tone-btn {
    border: none;
    border-radius: 7px;
    padding: 13px 20px;
    background: linear-gradient(135deg,#333,#000);
    color: #fff;
    font-size: 14px;
    font-weight: 600;
    transition: .2s;
}

.tone-btn:hover {
    color: #fff;
    background: linear-gradient(135deg,#555,#111);
    transform: translateY(-1px);
}

.tone-btn:disabled {
    opacity: .5;
    cursor: not-allowed;
    transform: none;
}

.stop-btn {
    background: linear-gradient(135deg,#555,#222);
}

#waveformCanvas {
    width: 100%;
    height: 190px;
    display: block;
    background: #111;
    border-radius: 9px;
}

.status-text {
    font-size: 13px;
    color: #777;
}

.status-dot {
    display: inline-block;
    height: 9px;
    width: 9px;
    border-radius: 50%;
    background: #aaa;
    margin-right: 5px;
}

.status-dot.active { background: #20b26b; }

.download-panel {
    background: #f8f8f8;
    padding: 20px;
    border: 1px solid #e8e8e8;
    border-radius: 10px;
}

.form-select {
    min-height: 45px;
    border-color: #ddd;
}

.form-select:focus {
    border-color: #777;
    box-shadow: none;
}

.progress { height: 8px; }

@media(max-width:767px) {
    .tone-generator { margin: 10px; padding: 15px; }
    .tone-panel { padding: 17px; }
    .frequency-value { font-size: 36px; }
    #waveformCanvas { height: 155px; }
}