* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 10px;
    transition: all 0.3s ease;
}

/* ダークモード全体スタイル */
body.dark-mode {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 10px;
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

/* ダークモード時のコンテナ */
body.dark-mode .container {
    background: #2a2a3e;
    color: #e0e0e0;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

/* ヘッダーセクション */
.header-section {
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 15px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 10px;
    margin-bottom: 20px;
}

h1 {
    text-align: center;
    color: white;
    font-size: 2em;
    font-weight: 300;
    letter-spacing: 1px;
    margin: 0;
}

/* ダークモード切り替えボタン */
.global-dark-mode-toggle {
    position: absolute;
    right: 20px;
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50px;
    padding: 8px 12px;
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 16px;
    display: flex;
    align-items: center;
    gap: 5px;
}

.global-dark-mode-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.05);
}

.global-dark-mode-toggle .dark-icon {
    display: none;
}

body.dark-mode .global-dark-mode-toggle .light-icon {
    display: none;
}

body.dark-mode .global-dark-mode-toggle .dark-icon {
    display: inline;
}

/* ダークモード時のヘッダー */
body.dark-mode .header-section {
    background: linear-gradient(135deg, #2d3748 0%, #1a202c 100%);
}

/* 注意書きセクション */
.notice-section {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 10px;
    margin: 0 15px 20px 15px;
    padding: 15px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.notice-content {
    color: white;
    text-align: center;
}

.notice-title {
    font-size: 1.2em;
    font-weight: bold;
    margin: 0 0 10px 0;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}

.notice-text {
    font-size: 0.9em;
    line-height: 1.5;
    margin: 0;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}

.notice-text strong {
    font-weight: bold;
    text-shadow: 2px 2px 3px rgba(0, 0, 0, 0.5);
}

/* ダークモード対応 */
body.dark-mode .notice-section {
    background: linear-gradient(135deg, #4a5568 0%, #2d3748 100%);
    border: 1px solid #4a5568;
}

.upload-section {
    padding: 15px;
    text-align: center;
    border-bottom: 1px solid #eee;
}

.upload-btn {
    display: inline-block;
    padding: 10px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 14px;
    font-weight: 500;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.upload-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.6);
}

#fileName {
    display: block;
    margin-top: 15px;
    color: #666;
    font-style: italic;
}

/* タブナビゲーション */
.tab-navigation {
    display: flex;
    margin-bottom: 15px;
    border-bottom: 2px solid #eee;
    transition: border-color 0.3s ease;
}

.tab-btn {
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 600;
    border: none;
    background: transparent;
    color: #666;
    cursor: pointer;
    border-bottom: 3px solid transparent;
    transition: all 0.3s ease;
}

.tab-btn.active {
    color: #667eea;
    border-bottom-color: #667eea;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1) 0%, rgba(118, 75, 162, 0.1) 100%);
}

.tab-btn:hover {
    color: #667eea;
    background: rgba(102, 126, 234, 0.05);
}

/* ダークモード時のタブナビゲーション */
body.dark-mode .tab-navigation {
    border-bottom-color: #444;
}

body.dark-mode .tab-btn {
    color: #b0b0b0;
}

body.dark-mode .tab-btn:hover {
    color: #8bb6ff;
    background: rgba(139, 182, 255, 0.1);
}

body.dark-mode .tab-btn.active {
    color: #8bb6ff;
    border-bottom-color: #8bb6ff;
    background: linear-gradient(135deg, rgba(139, 182, 255, 0.1) 0%, rgba(160, 120, 200, 0.1) 100%);
}

/* タブコンテンツ */
.tab-content {
    display: none;
}

.tab-content.active {
    display: flex;
    gap: 15px;
    align-items: flex-start;
}

/* 左側のコントロールエリア */
.controls-area {
    flex: 1;
    min-width: 400px;
}

/* 右側のプレビューエリア */
.preview-area {
    flex: 1;
    min-width: 400px;
    position: sticky;
    top: 10px;
}

.controls-section {
    padding: 15px;
    background: #f8f9fa;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 10px;
    border-radius: 10px;
    margin-bottom: 0;
    transition: all 0.3s ease;
}

.text-controls-section {
    padding: 15px;
    background: #f8f9fa;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 10px;
    border-radius: 10px;
    margin-bottom: 0;
    transition: all 0.3s ease;
}

.control-group {
    background: #f8f9fa;
    padding: 12px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

/* ダークモード時のコントロールエリア */
body.dark-mode .controls-section,
body.dark-mode .text-controls-section {
    background: #3d3d52;
}

body.dark-mode .control-group {
    background: #4a4a62;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.control-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
    color: #333;
    font-size: 13px;
    transition: color 0.3s ease;
}

.control-group input[type="range"] {
    width: 100%;
    margin-bottom: 5px;
    appearance: none;
    height: 6px;
    background: #ddd;
    border-radius: 3px;
    outline: none;
    transition: background 0.3s ease;
}

.control-group input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

.control-group input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

.control-group select {
    width: 100%;
    padding: 6px;
    border: 2px solid #ddd;
    border-radius: 4px;
    font-size: 13px;
    background: white;
    transition: all 0.3s ease;
}

/* ダークモード時のフォーム要素 */
body.dark-mode .control-group label {
    color: #e0e0e0;
}

body.dark-mode .control-group input[type="range"] {
    background: #555;
}

body.dark-mode .control-group select {
    background: #555;
    color: #e0e0e0;
    border-color: #666;
}

body.dark-mode .control-group select option {
    background: #555;
    color: #e0e0e0;
}

.control-group input[type="color"] {
    width: 50px;
    height: 30px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

.control-group span {
    font-weight: 600;
    color: #667eea;
    font-size: 12px;
}

button {
    grid-column: 1 / -1;
    padding: 8px 16px;
    font-size: 14px;
    font-weight: 600;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    margin: 5px;
}

#generateBtn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

#generateBtn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.6);
}

#downloadBtn {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
    box-shadow: 0 5px 15px rgba(40, 167, 69, 0.4);
}

#downloadBtn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(40, 167, 69, 0.6);
}

#downloadBtn:disabled {
    background: #ccc;
    cursor: not-allowed;
    box-shadow: none;
}

#downloadGifBtn {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    color: white;
    box-shadow: 0 5px 15px rgba(255, 107, 107, 0.4);
}

#downloadGifBtn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(255, 107, 107, 0.6);
}

#downloadGifBtn:disabled {
    background: #ccc;
    cursor: not-allowed;
    box-shadow: none;
}

#downloadRealGifBtn {
    background: linear-gradient(135deg, #9b59b6 0%, #8e44ad 100%);
    color: white;
    box-shadow: 0 5px 15px rgba(155, 89, 182, 0.4);
}

#downloadRealGifBtn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(155, 89, 182, 0.6);
}

#downloadRealGifBtn:disabled {
    background: #ccc;
    cursor: not-allowed;
    box-shadow: none;
}

/* テキストジェネレーター用ボタン */
#textGenerateBtn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

#textGenerateBtn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.6);
}

#textDownloadBtn {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
    box-shadow: 0 5px 15px rgba(40, 167, 69, 0.4);
}

#textDownloadBtn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(40, 167, 69, 0.6);
}

#textDownloadBtn:disabled {
    background: #ccc;
    cursor: not-allowed;
    box-shadow: none;
}

#textDownloadGifBtn {
    background: linear-gradient(135deg, #9b59b6 0%, #8e44ad 100%);
    color: white;
    box-shadow: 0 5px 15px rgba(155, 89, 182, 0.4);
}

#textDownloadGifBtn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(155, 89, 182, 0.6);
}

#textDownloadGifBtn:disabled {
    background: #ccc;
    cursor: not-allowed;
    box-shadow: none;
}

/* テキストキャンバス */
#textCanvas {
    max-width: 100%;
    max-height: 80vh;
    border: 2px solid #ddd;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    background-color: black;
    transition: all 0.3s ease;
    /* 透過背景の場合のチェッカーボード背景 */
    background-image: 
        linear-gradient(45deg, #ccc 25%, transparent 25%), 
        linear-gradient(-45deg, #ccc 25%, transparent 25%), 
        linear-gradient(45deg, transparent 75%, #ccc 75%), 
        linear-gradient(-45deg, transparent 75%, #ccc 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}

/* 透過背景が有効な場合のスタイル */
#textCanvas.transparent-bg {
    background-color: transparent;
}

#textCanvas:hover {
    border-color: #667eea;
    box-shadow: 0 8px 30px rgba(102, 126, 234, 0.2);
    transform: translateY(-2px);
}

/* テキスト入力フィールド */
#textInput {
    width: 100%;
    padding: 6px;
    border: 2px solid #ddd;
    border-radius: 4px;
    font-size: 13px;
    background: white;
    resize: vertical;
    min-height: 40px;
    font-family: inherit;
    color: #333;
    transition: all 0.3s ease;
}

/* ダークモード時のテキスト入力 */
body.dark-mode #textInput {
    background: #555;
    color: #e0e0e0;
    border-color: #666;
}

body.dark-mode #textInput::placeholder {
    color: #aaa;
}

/* ラジオボタンのスタイル */
.radio-group {
    display: flex;
    gap: 15px;
    align-items: center;
    margin-top: 5px;
}

.radio-group input[type="radio"] {
    margin: 0 5px 0 0;
    transform: scale(1.2);
    accent-color: #667eea;
}

.radio-group label {
    margin: 0 !important;
    font-weight: 500;
    color: #333;
    cursor: pointer;
    font-size: 13px;
    display: flex;
    align-items: center;
}

/* ダークモード時のラジオボタン */
body.dark-mode .radio-group label {
    color: #e0e0e0;
}

/* ダークモード・ライトモードプレビュー */
.mode-toggle-section {
    margin-top: 20px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    border: 2px solid #e9ecef;
    transition: all 0.3s ease;
}

.mode-toggle-section h3 {
    margin: 0 0 10px 0;
    font-size: 14px;
    font-weight: 600;
    color: #333;
    text-align: center;
    transition: color 0.3s ease;
}

/* ダークモード時のプレビューセクション */
body.dark-mode .mode-toggle-section,
body.dark-mode .slack-preview-section {
    background: #3d3d52;
    border-color: #555;
}

body.dark-mode .mode-toggle-section h3,
body.dark-mode .slack-preview-section h3 {
    color: #e0e0e0;
}

body.dark-mode .mode-preview-item h4,
body.dark-mode .slack-size-item h4 {
    color: #b0b0b0;
}

body.dark-mode .light-theme-demo,
body.dark-mode .slack-demo {
    border-color: #555;
}



.mode-preview {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.mode-preview-item {
    flex: 1;
    text-align: center;
}

.mode-preview-item h4 {
    margin: 0 0 8px 0;
    font-size: 12px;
    font-weight: 600;
    color: #666;
}

.light-theme-demo {
    background: white;
    padding: 10px;
    border-radius: 8px;
    border: 2px solid #ddd;
}

.dark-theme-demo {
    background: #2c2c2c;
    padding: 10px;
    border-radius: 8px;
    border: 2px solid #444;
}

#lightCanvas, #darkCanvas {
    width: 100%;
    max-width: 100px;
    height: auto;
    border-radius: 4px;
}

/* Slackスタンププレビュー */
.slack-preview-section {
    margin-top: 20px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    border: 2px solid #e9ecef;
    transition: all 0.3s ease;
}

.slack-preview-section h3 {
    margin: 0 0 15px 0;
    font-size: 14px;
    font-weight: 600;
    color: #333;
    text-align: center;
    transition: color 0.3s ease;
}

.slack-sizes {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.slack-size-item {
    text-align: center;
}

.slack-size-item h4 {
    margin: 0 0 8px 0;
    font-size: 12px;
    font-weight: 600;
    color: #666;
}

.slack-mode-previews {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.slack-mode-item {
    text-align: center;
}

.slack-mode-item span {
    display: block;
    font-size: 10px;
    font-weight: 600;
    color: #666;
    margin-bottom: 4px;
}

.slack-demo {
    padding: 8px;
    border-radius: 8px;
    border: 2px solid #ddd;
    display: flex;
    justify-content: center;
    align-items: center;
}

.slack-demo.slack-light {
    background: #f8f9fa;
}

.slack-demo.slack-dark {
    background: #2c2c2c;
    border-color: #555;
}

#slack32LightCanvas,
#slack32DarkCanvas {
    border-radius: 4px;
    background: transparent;
    /* 32×32pxではピクセル化を維持 */
    image-rendering: pixelated;
    image-rendering: -moz-crisp-edges;
    image-rendering: crisp-edges;
}

#slack64LightCanvas,
#slack64DarkCanvas {
    border-radius: 4px;
    background: transparent;
    /* 64×64pxでは高品質レンダリング */
    image-rendering: auto;
    image-rendering: high-quality;
    image-rendering: -webkit-optimize-contrast;
}

/* ダークモード時のSlackプレビュー */
body.dark-mode .slack-mode-item span {
    color: #b0b0b0;
}

.canvas-section {
    padding: 15px;
    text-align: center;
    background: #f8f9fa;
    border-radius: 10px;
    height: fit-content;
}

.preview-info {
    margin-bottom: 10px;
    padding: 10px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 8px;
    color: white;
    box-shadow: 0 3px 10px rgba(102, 126, 234, 0.3);
}

.preview-info p {
    margin: 3px 0;
    font-size: 12px;
    font-weight: 500;
}

#canvas {
    max-width: 100%;
    max-height: 80vh;
    border: 2px solid #ddd;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    background-color: white;
    transition: all 0.3s ease;
}

#canvas:hover {
    border-color: #667eea;
    box-shadow: 0 8px 30px rgba(102, 126, 234, 0.2);
    transform: translateY(-2px);
}

#singleColorGroup {
    display: block;
}

#singleColorGroup.hidden {
    display: none;
}

@media (max-width: 1200px) and (min-width: 769px) {
    .tab-content.active {
        flex-direction: column;
        gap: 15px;
    }
    
    .controls-area,
    .preview-area {
        min-width: unset;
        flex: none;
    }
    
    /* タブレット：プレビューエリアを上部に配置 */
    .preview-area {
        order: -1;
        position: static;
        background: white;
        border-radius: 10px;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
        padding: 15px;
        margin-bottom: 10px;
    }
    
    /* ダークモード時のタブレットプレビューエリア */
    body.dark-mode .preview-area {
        background: #2a2a3e;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
    }
    
    /* タブレット：キャンバスサイズ調整 */
    #canvas, #textCanvas {
        max-width: 100%;
        max-height: 60vh;
    }
    
    .controls-area {
        order: 1;
    }
}

@media (max-width: 768px) {
    .controls-section {
        grid-template-columns: 1fr;
        padding: 10px;
    }
    
    .text-controls-section {
        grid-template-columns: 1fr;
        padding: 10px;
    }
    
    .header-section {
        padding: 10px;
        flex-direction: column;
        gap: 10px;
    }
    
    .global-dark-mode-toggle {
        position: static;
        align-self: center;
    }
    
    h1 {
        font-size: 1.8em;
        margin: 0;
    }
    
    .upload-section, .canvas-section {
        padding: 10px;
    }
    
    .container {
        padding: 5px;
    }
    
    /* モバイル専用：タブコンテンツレイアウト調整 */
    .tab-content.active {
        flex-direction: column;
        gap: 10px;
    }
    
    /* モバイル専用：集中線ジェネレーターのレイアウト最適化 */
    #concentration-tab.tab-content.active {
        display: block;
    }
    
    /* モバイル専用：プレビューエリアをコンパクトに上部配置 */
    .preview-area {
        order: -1;
        position: static;
        background: white;
        border-radius: 10px;
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
        margin-bottom: 10px;
        padding: 8px;
        width: 100%;
        max-width: 100%;
        overflow-x: auto;
    }
    
    /* ダークモード時のプレビューエリア */
    body.dark-mode .preview-area {
        background: #2a2a3e;
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    }
    
    /* モバイル専用：キャンバスサイズ調整 */
    #canvas {
        max-width: 100%;
        max-height: 30vh;
        width: auto;
        height: auto;
    }
    
    /* モバイル専用：テキストキャンバスサイズ調整 */
    #textCanvas {
        max-width: 100%;
        max-height: 30vh;
        width: auto;
        height: auto;
    }
    
    /* モバイル専用：プレビュー情報をよりコンパクトに */
    .preview-info {
        margin-bottom: 5px;
        padding: 8px;
    }
    
    .preview-info p {
        font-size: 11px;
        margin: 2px 0;
    }
    
    /* モバイル専用：コントロールエリアの改善 */
    .controls-area {
        order: 1;
    }
    
    /* プレビューセクションのモバイル対応 */
    .mode-toggle-section,
    .slack-preview-section {
        margin-top: 15px;
        padding: 8px;
        width: 100%;
        max-width: 100%;
        overflow-x: auto;
        box-sizing: border-box;
    }
    
    .mode-toggle-section h3,
    .slack-preview-section h3 {
        font-size: 13px;
        margin-bottom: 8px;
    }
    
    .mode-preview {
        flex-direction: column;
        gap: 6px;
        align-items: center;
    }
    
    .mode-preview-item {
        width: 100%;
        max-width: 120px;
    }
    
    /* Slackプレビューのモバイル最適化 */
    .slack-sizes {
        flex-direction: column;
        gap: 10px;
        align-items: center;
    }
    
    .slack-mode-previews {
        gap: 5px;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .slack-demo {
        padding: 4px;
        min-width: 40px;
    }
    
    #lightCanvas, #darkCanvas {
        max-width: 60px;
        max-height: 60px;
    }
    
    #slack32LightCanvas,
    #slack32DarkCanvas,
    #slack64LightCanvas,
    #slack64DarkCanvas {
        max-width: 32px;
        max-height: 32px;
    }
    
    /* モバイル専用：注意書きセクションの調整 */
    .notice-section {
        margin: 0 5px 15px 5px;
        padding: 10px;
    }
    
    .notice-title {
        font-size: 1.1em;
    }
    
    .notice-text {
        font-size: 0.85em;
        line-height: 1.4;
    }
}

/* ダークモード時のその他の要素 */
body.dark-mode #fileName {
    color: #b0b0b0;
}

body.dark-mode .canvas-section {
    background: #3d3d52;
}

body.dark-mode .preview-info {
    background: linear-gradient(135deg, #4a5568 0%, #2d3748 100%);
}

body.dark-mode #canvas,
body.dark-mode #textCanvas {
    border-color: #555;
}

body.dark-mode .control-group span {
    color: #8bb6ff;
}

/* 超小画面（スマートフォン縦向き）対応 */
@media (max-width: 480px) {
    .container {
        padding: 3px;
        margin: 5px;
    }
    
    h1 {
        font-size: 1.5em;
    }
    
    .notice-section {
        margin: 0 3px 10px 3px;
        padding: 8px;
    }
    
    .notice-title {
        font-size: 1em;
    }
    
    .notice-text {
        font-size: 0.8em;
    }
    
    .tab-btn {
        padding: 8px 12px;
        font-size: 12px;
    }
    
    .preview-area {
        margin-bottom: 8px;
        padding: 6px;
        width: 100%;
        max-width: 100%;
        overflow-x: auto;
        box-sizing: border-box;
    }
    
    .mode-toggle-section,
    .slack-preview-section {
        padding: 6px;
        margin-top: 10px;
    }
    
    .slack-mode-previews {
        gap: 3px;
    }
    
    .slack-demo {
        padding: 3px;
        min-width: 36px;
    }
    
    #slack32LightCanvas,
    #slack32DarkCanvas {
        max-width: 28px;
        max-height: 28px;
    }
    
    #slack64LightCanvas,
    #slack64DarkCanvas {
        max-width: 48px;
        max-height: 48px;
        /* モバイルでも高品質レンダリング */
        image-rendering: auto;
    }
    
    #canvas, #textCanvas {
        max-height: 25vh;
    }
    
    .preview-info {
        padding: 6px;
    }
    
    .preview-info p {
        font-size: 10px;
        margin: 1px 0;
    }
    
    .controls-section, .text-controls-section {
        padding: 8px;
        gap: 8px;
        width: 100%;
        max-width: 100%;
        box-sizing: border-box;
    }
    
    .control-group {
        padding: 8px;
        width: 100%;
        max-width: 100%;
        box-sizing: border-box;
    }
    
    .control-group label {
        font-size: 12px;
    }
    
    button {
        padding: 6px 12px;
        font-size: 12px;
        margin: 3px;
        width: 100%;
        max-width: 100%;
        box-sizing: border-box;
    }
    
    .control-group input[type="range"] {
        width: 100%;
        max-width: 100%;
    }
    
    .control-group select {
        width: 100%;
        max-width: 100%;
        box-sizing: border-box;
    }
    
    .radio-group {
        flex-wrap: wrap;
        gap: 8px;
        justify-content: flex-start;
    }
}

/* ナビゲーションメニュー */
.nav-menu {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin: 20px 0;
    padding: 15px;
    background-color: #f5f5f5;
    border-radius: 10px;
    flex-wrap: wrap;
}

.dark-mode .nav-menu {
    background-color: #333;
}

.nav-menu a {
    color: #4CAF50;
    text-decoration: none;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: 5px;
    transition: all 0.3s ease;
}

.nav-menu a:hover {
    background-color: #4CAF50;
    color: white;
}

.dark-mode .nav-menu a {
    color: #81C784;
}

.dark-mode .nav-menu a:hover {
    background-color: #4CAF50;
    color: white;
}

/* Google AdSense バナー広告 */
.ad-banner {
    text-align: center;
    margin: 20px 0;
    padding: 10px;
    background-color: #f9f9f9;
    border: 1px solid #e0e0e0;
    border-radius: 5px;
    max-width: 728px;
    margin-left: auto;
    margin-right: auto;
    transition: all 0.3s ease;
}

.ad-placeholder {
    padding: 20px;
    background-color: #f0f0f0;
    border: 1px dashed #ccc;
    border-radius: 3px;
    color: #999;
    font-size: 12px;
    text-align: center;
    min-height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ダークモード対応 */
.dark-mode .ad-banner {
    background-color: #2a2a2a;
    border-color: #444;
}

.dark-mode .ad-placeholder {
    background-color: #333;
    border-color: #555;
    color: #666;
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .ad-banner {
        max-width: 100%;
        margin: 15px 10px;
    }
    
    .ad-placeholder {
        min-height: 60px;
    }
}

/* フッター */
.footer {
    text-align: center;
    padding: 20px;
    margin-top: 30px;
    color: #666;
    font-size: 14px;
    border-top: 1px solid #eee;
    transition: all 0.3s ease;
}

.footer p {
    margin: 0;
    font-weight: 500;
}

/* ダークモード時のフッター */
body.dark-mode .footer {
    color: #b0b0b0;
    border-top-color: #444;
}