:root {
    --primary-color: #0052CC;
    --primary-hover: #0747A6;
    --secondary-color: #42526E;
    --success-color: #00875A;
    --danger-color: #DE350B;
    --warning-color: #FF991F;
    --background: #F4F5F7;
    --surface: #FFFFFF;
    --text-primary: #172B4D;
    --text-secondary: #5E6C84;
    --border-color: #DFE1E6;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 20px rgba(0, 0, 0, 0.15);
    --border-radius: 8px;
    --transition: all 0.2s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
}

/* ヘッダー */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-title {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.logo {
    width: 32px;
    height: 32px;
    color: var(--primary-color);
}

.language-selector select {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--surface);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
}

.language-selector select:hover {
    border-color: var(--primary-color);
}

/* メインコンテンツ */
.main-content {
    flex: 1;
    padding: 2rem 0;
}

/* カード */
.card {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-md);
}

.card h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

/* 入力セクション */
.input-section {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
    color: white;
}

.input-section h2 {
    color: white;
}

.input-group {
    display: flex;
    gap: 12px;
    margin-bottom: 1rem;
}

.url-input {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--border-radius);
    font-size: 16px;
    background: rgba(255, 255, 255, 0.1);
    color: white;
    transition: var(--transition);
}

.url-input::placeholder {
    color: rgba(255, 255, 255, 0.7);
}

.url-input:focus {
    outline: none;
    border-color: white;
    background: rgba(255, 255, 255, 0.2);
}

.input-section .url-input {
    color: white;
}

.input-section .url-input::placeholder {
    color: rgba(255, 255, 255, 0.8);
}

/* ボタン */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: white;
    color: var(--primary-color);
}

.btn-primary:hover {
    background: #F4F5F7;
    transform: translateY(-1px);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
}

.card .btn-primary {
    background: var(--primary-color);
    color: white;
}

.card .btn-primary:hover {
    background: var(--primary-hover);
}

.card .btn-secondary {
    background: var(--background);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.card .btn-secondary:hover {
    background: var(--border-color);
}

.btn-small {
    padding: 6px 12px;
    font-size: 14px;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
}

.btn-danger:hover {
    background: #BF2600;
}

/* サンプルURL */
.sample-urls {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
    color: rgba(255, 255, 255, 0.9);
}

.sample-url-btn {
    padding: 6px 12px;
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 20px;
    color: white;
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
}

.sample-url-btn:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-1px);
}

/* URL構成要素 */
.url-parts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.url-part {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.url-part label {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 14px;
}

.part-input {
    padding: 10px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 15px;
    transition: var(--transition);
    background: var(--surface);
}

.part-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 82, 204, 0.1);
}

.part-description {
    color: var(--text-secondary);
    font-size: 12px;
}

/* クエリパラメータ */
.query-params-container {
    margin-bottom: 1rem;
}

.query-param-row {
    display: grid;
    grid-template-columns: 1fr 2fr auto;
    gap: 12px;
    margin-bottom: 12px;
    align-items: center;
}

.param-key,
.param-value {
    padding: 10px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 15px;
    transition: var(--transition);
}

.param-key:focus,
.param-value:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* エンコード/デコード */
.encode-decode-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.encode-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.encode-group label {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 14px;
}

.encode-group textarea {
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-family: 'Monaco', 'Menlo', monospace;
    font-size: 14px;
    resize: vertical;
    background: #F4F5F7;
}

/* QRコード */
.qr-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.qr-container {
    padding: 20px;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.qr-container canvas {
    display: block;
}

/* 短縮URL展開 */
.shortener-section p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.expand-result {
    margin-top: 1rem;
}

/* URL情報 */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px;
    background: var(--background);
    border-radius: var(--border-radius);
}

.info-label {
    font-weight: 500;
    color: var(--text-secondary);
}

.info-value {
    font-weight: 600;
    color: var(--text-primary);
}

/* フッター */
.footer {
    background: var(--surface);
    border-top: 1px solid var(--border-color);
    padding: 1.5rem 0;
    text-align: center;
    color: var(--text-secondary);
    margin-top: auto;
}

/* トースト通知 */
.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 12px 20px;
    border-radius: var(--border-radius);
    color: white;
    font-size: 14px;
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 1000;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

.toast-success {
    background: var(--success-color);
}

.toast-error {
    background: var(--danger-color);
}

/* レスポンシブ */
@media (max-width: 768px) {
    .header-title {
        font-size: 1.25rem;
    }
    
    .logo {
        width: 28px;
        height: 28px;
    }
    
    .input-group {
        flex-direction: column;
    }
    
    .url-parts-grid {
        grid-template-columns: 1fr;
    }
    
    .query-param-row {
        grid-template-columns: 1fr;
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
    
    .sample-urls {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* アニメーション */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.results-container > * {
    animation: fadeIn 0.3s ease forwards;
}

/* スクロールバー */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}