:root {
    --primary-bg: #1a1a1a;
    --secondary-bg: #2a2a2a;
    --tertiary-bg: #3a3a3a;
    --accent-color: #00aaff;
    --text-color: #f0f0f0;
    --border-color: #4a4a4a;
    --play-color: #28a745;
    --stop-color: #dc3545;
    --play-color-rgb: 40, 167, 69;
    --stop-color-rgb: 220, 53, 69;
    --footer-height: 90px;
}

*, *::before, *::after {
    box-sizing: border-box;
}

/* --- Base & Container --- */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--primary-bg);
    color: var(--text-color);
    margin: 0;
    -webkit-tap-highlight-color: transparent;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    padding: 16px;
    padding-bottom: var(--footer-height);
    text-align: center;
}

.header-container {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto 24px;
    max-width: 500px;
    position: relative;
}

h1 {
    color: var(--accent-color);
    margin: 0;
    text-align: center;
}

.header-help-button {
    position: absolute;
    right: 0;
    width: 32px;
    height: 32px;
    font-size: 1.2em;
    line-height: 30px;
}

/* --- Generic Controls --- */
button {
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 16px 24px;
    font-size: 1.1em;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s, border-color 0.2s, box-shadow 0.2s;
}

button:active {
    transform: scale(0.96);
}

button:disabled {
    background-color: var(--tertiary-bg);
    color: #777;
    cursor: not-allowed;
    transform: scale(1);
    border-color: var(--tertiary-bg) !important;
    box-shadow: none !important;
}

/* --- Top Bar --- */
.global-controls {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    align-items: flex-start;
    background-color: var(--secondary-bg);
    padding: 24px 16px;
    border-radius: 12px;
    margin: 0 auto 24px;
    gap: 16px;
    max-width: 500px;
}

.control-group {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
}

.control-group label {
    font-size: 1em;
}

.display-button {
    background-color: var(--tertiary-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 16px;
    font-size: 1.1em;
    text-align: center;
    width: 100%;
}

#bpm-rate-display-button {
    white-space: nowrap;
}

/* --- Sequencer --- */
.sequencer-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, 1fr);
    gap: 8px;
    background-color: var(--secondary-bg);
    padding: 16px;
    border-radius: 12px;
    margin: 24px auto;
    width: 100%;
    max-width: 500px;
    aspect-ratio: 1 / 1;
}

.step {
    background-color: var(--tertiary-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    aspect-ratio: 1 / 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s, opacity 0.2s;
    position: relative;
    padding: 4px;
    overflow: hidden;
    min-width: 0;
    min-height: 0;
}

.step.active {
    background-color: rgba(var(--play-color-rgb), 0.5);
    color: var(--text-color);
    transform: scale(1.05);
    border-color: var(--play-color);
    box-shadow: 0 0 12px var(--play-color);
}

.step.active-preview {
    background-color: rgba(0, 170, 255, 0.5);
    border-color: var(--accent-color);
    box-shadow: 0 0 12px var(--accent-color);
    transform: scale(1.05);
}

.step.dragging {
    opacity: 0.4;
}

.step.drag-over {
    border-style: dashed;
    border-color: var(--accent-color);
}

.step.disabled {
    opacity: 0.3;
    cursor: default;
    background-color: var(--primary-bg);
}

.step.step-disabled {
    opacity: 0.4;
}

.step-number {
    position: absolute;
    top: 4px;
    left: 4px;
    font-size: 0.7em;
    opacity: 0.5;
}

.step-transpose {
    font-size: 1.6em;
    font-weight: bold;
}

.step-note {
    font-size: 0.9em;
    opacity: 0.8;
}

/* --- SEQ MAX --- */
.seq-max-controls {
    background-color: var(--secondary-bg);
    padding: 16px;
    border-radius: 12px;
    margin: 24px auto;
    max-width: 500px;
    text-align: center;
}

.seq-max-controls label {
    display: block;
    margin-bottom: 16px;
    font-size: 1em;
    font-weight: bold;
}

.seq-max-buttons {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    gap: 8px;
}

.seq-max-button {
    background-color: var(--tertiary-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 8px 0;
    font-size: 1em;
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s;
}

.seq-max-button.active {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
    font-weight: bold;
}

/* --- Footer & Action Buttons --- */
.footer-menu {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--footer-height);
    background: linear-gradient(180deg, rgba(50, 50, 50, 0.7), rgba(30, 30, 30, 0.8));
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.05);
    display: flex;
    align-items: center;
    justify-content: space-evenly;
    padding: 0 16px;
    gap: 16px;
    z-index: 500;
}

.footer-button {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-color);
    border-radius: 50%;
    width: 56px;
    height: 56px;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0;
    cursor: pointer;
    transition: all 0.2s ease-in-out;
    box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.05), 0 2px 4px rgba(0,0,0,0.2);
}

.footer-button:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
    box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.05), 0 4px 8px rgba(0,0,0,0.3);
}

.footer-button:active {
    background-color: rgba(255, 255, 255, 0.08);
    transform: scale(0.96);
    box-shadow: inset 0 2px 2px rgba(0,0,0,0.1);
}

.footer-button svg {
    fill: var(--text-color);
    opacity: 0.9;
    width: 28px;
    height: 28px;
    filter: drop-shadow(0 1px 1px rgba(0, 0, 0, 0.4));
}

.play-stop-button {
    width: 140px;
    height: 56px;
    border-radius: 28px;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: rgba(var(--play-color-rgb), 0.2);
    border: 2px solid var(--play-color);
    box-shadow: 0 0 15px -2px var(--play-color);
    color: white;
    font-size: 1.2em;
    font-weight: bold;
    overflow: hidden; /* Hide content that doesn't fit */
    cursor: pointer;
    transition: all 0.2s ease-in-out;
}

.play-stop-button:active {
    transform: scale(0.96);
}

.play-stop-button.playing {
    background-color: rgba(var(--stop-color-rgb), 0.2);
    border-color: var(--stop-color);
    box-shadow: 0 0 15px -2px var(--stop-color);
}

.play-stop-button .play-content,
.play-stop-button .stop-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.play-stop-button .stop-content { display: none; }
.play-stop-button.playing .play-content { display: none; }
.play-stop-button.playing .stop-content { display: flex; }

.play-stop-button svg {
    fill: white;
    width: 24px;
    height: 24px;
}


/* --- Modals --- */
.modal {
    display: none; 
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.75);
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: rgba(42, 42, 42, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 24px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    width: 90%;
    max-width: 400px;
    text-align: center;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.modal-header h2 {
    margin: 0;
    color: var(--accent-color);
}

.close-button {
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 2.5em;
    font-weight: bold;
    line-height: 1;
    padding: 0 8px;
    cursor: pointer;
    opacity: 0.7;
}

.close-button:hover {
    opacity: 1;
}

.modal-footer {
    display: flex;
    justify-content: space-between;
    margin-top: 32px;
    gap: 8px;
}

.modal-footer button {
    flex: 1;
    padding: 16px 12px; /* Adjust padding to prevent overflow */
    min-width: 0; /* Allow buttons to shrink */
}

#reset-button {
    background-color: #888;
}

.transpose-info {
    display: flex;
    justify-content: space-around;
    margin-bottom: 32px;
    gap: 8px;
}

.info-box {
    background-color: var(--tertiary-bg);
    padding: 16px;
    border-radius: 8px;
    width: 32%;
    font-size: 1em;
    font-weight: bold;
    min-height: 48px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.transpose-selector {
    position: relative;
    height: 60px;
    background-color: var(--tertiary-bg);
    border-radius: 10px;
    display: flex;
    align-items: center;
    margin: 40px 16px 0;
    touch-action: none; 
}

.transpose-labels {
    display: flex;
    justify-content: space-between;
    margin: 8px 24px 0;
    font-size: 0.9em;
    color: var(--text-color);
    opacity: 0.7;
}

.selector-track {
    width: 100%;
    height: 6px;
    background-color: var(--border-color);
    border-radius: 3px;
    position: relative;
}

.selector-ticks {
    position: absolute;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
}

.tick {
    position: absolute;
    width: 2px;
    height: 10px;
    background-color: var(--border-color);
    transform: translateX(-50%);
}

.tick.tick-major {
    height: 20px;
    background-color: var(--accent-color);
}

.selector-handle {
    position: absolute;
    width: 30px;
    height: 30px;
    background-color: var(--accent-color);
    border-radius: 50%;
    border: 3px solid var(--secondary-bg);
    top: 50%;
    transform: translate(-50%, -50%);
    cursor: pointer;
}

#bpm-rate-modal .modal-content {
    max-width: 450px;
}

.bpm-editor, .rate-editor {
    margin-bottom: 24px;
}

.bpm-editor h3, .rate-editor h3 {
    margin-top: 0;
    margin-bottom: 16px;
    font-size: 1.2em;
    color: var(--text-color);
    opacity: 0.9;
}

.bpm-adjust-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.bpm-adjust-controls button {
    width: 60px;
    height: 60px;
    font-size: 1.5em;
    border-radius: 50%;
    background-color: var(--tertiary-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0;
    line-height: 1;
}

#modal-bpm-value {
    font-size: 2.5em;
    font-weight: bold;
    color: var(--accent-color);
    min-width: 100px;
}

.rate-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 8px;
}

.rate-buttons button {
    background-color: var(--tertiary-bg);
    padding: 16px 8px;
    font-size: 1em;
    border: 1px solid var(--border-color);
}

.rate-buttons button.selected {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
}

#done-bpm-rate-button,
#done-base-note-button {
    width: 100%;
    padding: 24px;
    font-size: 1.3em;
}

#modal-step-number {
    color: var(--text-color);
    opacity: 0.6;
    font-weight: normal;
    font-size: 0.9em;
    margin-left: 8px;
}

.note-name-editor, .octave-editor, .waveform-editor {
    margin-bottom: 24px;
}

.note-name-editor h3, .octave-editor h3, .waveform-editor h3 {
    margin-top: 0;
    margin-bottom: 16px;
    font-size: 1.2em;
    color: var(--text-color);
    opacity: 0.9;
}

.note-name-buttons {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 8px;
}

.octave-buttons {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 8px;
}

.waveform-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
}

.note-name-buttons button, .octave-buttons button, .waveform-buttons button {
    background-color: var(--tertiary-bg);
    padding: 16px 8px;
    font-size: 1em;
    border: 1px solid var(--border-color);
    border-radius: 6px;
}

.note-name-buttons button.selected, .octave-buttons button.selected, .waveform-buttons button.selected {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
    font-weight: bold;
}

.melody-gen-control {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.melody-gen-control label {
    font-size: 1.2em;
    opacity: 0.9;
}

.melody-gen-control select {
    background-color: var(--tertiary-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 16px;
    font-size: 1.1em;
    width: 60%;
    text-align: center;
}

/* --- Toggle Switch for Step Enable --- */
.step-enable-control {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-top: 24px;
    gap: 16px;
}

.step-enable-control label {
    font-size: 1.1em;
    color: var(--text-color);
    opacity: 0.9;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--tertiary-bg);
    transition: .4s;
    border-radius: 34px;
    border: 1px solid var(--border-color);
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 3px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

input:checked + .slider:before {
    transform: translateX(26px);
}

/* --- Share Modal --- */
.share-url-display {
    width: 100%;
    background-color: var(--primary-bg);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 12px;
    border-radius: 6px;
    font-size: 1em;
    margin: 16px 0;
    text-align: center;
}

.share-buttons-container {
    display: flex;
    gap: 16px;
    margin-top: 24px;
}

.share-buttons-container .action-button {
    flex: 1;
    padding: 16px;
    font-size: 1em;
}

#share-x-button {
    background-color: #1DA1F2; /* Twitter Blue */
}

/* Melody Gen Modal Additions */
.radio-group {
    display: flex;
    gap: 8px;
    width: 60%;
}

.radio-button {
    flex: 1;
    background-color: var(--tertiary-bg);
    padding: 16px 8px;
    font-size: 1em;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-color);
}

.radio-button.selected {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
    font-weight: bold;
}

.slider-container {
    display: flex;
    align-items: center;
    gap: 16px;
    width: 60%;
}

.slider-container input[type="range"] {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 8px;
    background: var(--tertiary-bg);
    border-radius: 5px;
    outline: none;
    opacity: 0.7;
    transition: opacity .2s;
}

.slider-container input[type="range"]:hover {
    opacity: 1;
}

.slider-container input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 24px;
    height: 24px;
    background: var(--accent-color);
    cursor: pointer;
    border-radius: 50%;
}

.slider-container input[type="range"]::-moz-range-thumb {
    width: 24px;
    height: 24px;
    background: var(--accent-color);
    cursor: pointer;
    border-radius: 50%;
}

#melody-rest-probability-value {
    font-size: 1.1em;
    font-weight: bold;
    min-width: 50px;
    text-align: right;
}

/* Help Button & Modal */
.help-button {
    background: var(--tertiary-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 24px;
    height: 24px;
    font-size: 0.9em;
    font-weight: bold;
    padding: 0;
    margin-left: 8px;
    cursor: pointer;
    line-height: 22px; /* Center the '_?_' */
    vertical-align: middle; /* Align with label text */
}

.help-button:active {
    transform: scale(0.9);
}

.language-switcher {
    display: flex;
    justify-content: center;
    gap: 10px;
    width: 100%;
}

.lang-button {
    background-color: var(--tertiary-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    padding: 8px 16px;
    font-size: 0.9em;
}

.lang-button.selected {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
}

#help-modal-content-body {
    text-align: left;
    line-height: 1.6;
    max-height: 60vh;
    overflow-y: auto;
    padding-right: 16px; /* Add some padding for the scrollbar */
}

#help-modal-content {
    white-space: pre-wrap;
}

/* --- App Footer --- */
.app-footer {
    margin-top: 24px;
    flex-shrink: 0;
    text-align: center;
    padding: 20px 16px;
    font-size: 0.85em;
    color: rgba(240, 240, 240, 0.5);
    line-height: 1.5;
}

.app-footer p {
    margin: 5px 0;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin: 12px 0;
}

.footer-links a {
    color: rgba(240, 240, 240, 0.7);
    text-decoration: none;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--accent-color);
}

.footer-links a svg {
    width: 26px;
    height: 26px;
    fill: currentColor;
}

.copyright {
    font-size: 0.9em;
    opacity: 0.6;
    margin-top: 12px;
}

/* --- Notification Modal --- */
#notification-modal .modal-footer button {
    width: 100%;
    padding: 16px;
    font-size: 1.2em;
}

#notification-modal-message {
    line-height: 1.6;
    font-size: 1.1em;
    margin: 0;
}