:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
    --radius: 12px;
}

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

body {
    font-family: 'Inter', 'Noto Sans JP', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    padding: 2rem;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.input-section {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 1.5rem;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-main);
}

textarea {
    width: 100%;
    height: 120px;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-family: inherit;
    font-size: 1rem;
    resize: vertical;
    transition: border-color 0.2s;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.controls {
    text-align: center;
    margin-bottom: 2rem;
}

.primary-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: var(--shadow-md);
}

.primary-btn:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 6px 8px -1px rgba(0,0,0,0.15);
}

.primary-btn:active {
    transform: translateY(0);
}

.results-section h2 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-main);
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.result-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: transform 0.2s;
}

.result-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.result-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.result-text {
    font-size: 1.1rem;
    color: var(--text-main);
    word-break: break-all;
    background: #f1f5f9;
    padding: 0.75rem;
    border-radius: 6px;
}

.copy-btn {
    margin-top: 0.5rem;
    background: none;
    border: none;
    color: var(--primary-color);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    padding: 0;
}

.copy-btn:hover {
    text-decoration: underline;
}

@media (max-width: 600px) {
    body {
        padding: 1rem;
    }
    
    header h1 {
        font-size: 2rem;
    }
}