:root {
    --primary-color: #0066ff;
    --primary-hover: #0052cc;
    --success-color: #00b341;
    --error-color: #ff3333;
    --text-primary: #1a1a1a;
    --text-secondary: #666;
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --border-color: #dee2e6;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition: all 0.2s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 800px;
    padding: 40px;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

header {
    text-align: center;
    margin-bottom: 40px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 8px;
}

.logo {
    font-size: 3rem;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 20px;
}

.lang-selector {
    display: flex;
    gap: 8px;
    justify-content: center;
}

.lang-btn {
    background: var(--bg-secondary);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    padding: 8px 12px;
    font-size: 1.2rem;
    cursor: pointer;
    transition: var(--transition);
}

.lang-btn:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
}

.lang-btn.active {
    border-color: var(--primary-color);
    background: var(--primary-color);
    filter: contrast(1.2);
}

.input-section {
    margin-bottom: 32px;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.input-wrapper {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
}

input[type="url"] {
    flex: 1;
    padding: 14px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: var(--transition);
    font-family: 'Courier New', monospace;
}

input[type="url"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.icon-btn {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 12px 16px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.icon-btn:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
}

.icon-btn.success {
    color: var(--success-color);
    border-color: var(--success-color);
}

.icon-btn.copied {
    animation: checkmark 0.5s ease;
}

@keyframes checkmark {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.2);
    }
}

.button-group {
    display: flex;
    gap: 12px;
}

.primary-btn, .secondary-btn {
    padding: 14px 28px;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: none;
}

.primary-btn {
    background: var(--primary-color);
    color: white;
    flex: 1;
}

.primary-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.secondary-btn {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.secondary-btn:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
}

.result-section {
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    padding: 24px;
    margin-bottom: 32px;
    transition: var(--transition);
}

.result-section.hidden {
    display: none;
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 16px;
}

.result-header h2 {
    font-size: 1.3rem;
    color: var(--text-primary);
}

.stats {
    display: flex;
    gap: 20px;
}

.stat-item {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.stat-item strong {
    color: var(--primary-color);
    font-size: 1.1rem;
    margin-left: 4px;
}

.result-url {
    display: flex;
    gap: 8px;
}

.result-url input {
    background: var(--bg-primary);
}

.removed-params {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.removed-params.hidden {
    display: none;
}

.removed-params h3 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.params-list {
    display: grid;
    gap: 8px;
}

.param-item {
    display: flex;
    justify-content: space-between;
    padding: 8px 12px;
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

.param-key {
    color: var(--error-color);
    font-weight: 600;
}

.param-value {
    color: var(--text-secondary);
    text-overflow: ellipsis;
    overflow: hidden;
    white-space: nowrap;
    max-width: 60%;
}

.info-section {
    margin-top: 40px;
}

.info-section h2 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    text-align: center;
    color: var(--text-primary);
}

.supported-sites {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 12px;
    margin-bottom: 32px;
}

.site-card {
    background: var(--bg-secondary);
    padding: 16px;
    border-radius: var(--radius-md);
    text-align: center;
    transition: var(--transition);
    cursor: default;
}

.site-card:hover {
    background: var(--bg-tertiary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.site-icon {
    display: block;
    font-size: 2rem;
    margin-bottom: 8px;
}

.features {
    background: var(--bg-secondary);
    padding: 24px;
    border-radius: var(--radius-md);
}

.features h3 {
    font-size: 1.2rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.features ul {
    list-style: none;
}

.features li {
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.features li:last-child {
    border-bottom: none;
}

footer {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text-primary);
    color: white;
    padding: 14px 24px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transition: var(--transition);
    z-index: 1000;
    font-weight: 500;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

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

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

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

/* レスポンシブデザイン */
@media (max-width: 640px) {
    .container {
        padding: 24px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .logo {
        font-size: 2.5rem;
    }
    
    .button-group {
        flex-direction: column;
    }
    
    .stats {
        flex-direction: column;
        gap: 8px;
    }
    
    .result-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .supported-sites {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    }
}