/* --- アプリ本体のコンテナ --- */
#in-app {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
    background-color: #0f172a;
    border: 1px solid #334155;
    padding: 2.5rem;
    font-family: "Inter", sans-serif;
}

#in-app .hidden { display: none !important; }

/* --- 変換オプションエリア --- */
.convert-options {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: rgba(30, 41, 59, 0.3);
    border: 1px solid #1e293b;
}
.option-title {
    font-size: 0.75rem;
    color: #60a5fa;
    font-weight: bold;
    margin-bottom: 1rem;
    font-family: 'Roboto Mono', monospace;
    text-transform: uppercase;
}
.checkbox-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
}
.check-item {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    cursor: pointer;
    font-size: 0.9rem;
    color: #cbd5e1;
}
.check-item input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: #3b82f6;
}

/* --- テキストエリア --- */
.text-area-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 2rem;
}
@media (max-width: 768px) {
    .text-area-grid { grid-template-columns: 1fr; }
}
.text-block label {
    display: block;
    font-size: 0.75rem;
    color: #94a3b8;
    margin-bottom: 0.8rem;
    font-family: 'Roboto Mono', monospace;
}
textarea {
    width: 100%;
    height: 300px;
    background: #0a0c10;
    border: 1px solid #334155;
    color: #f8fafc;
    padding: 1rem;
    font-size: 0.95rem;
    line-height: 1.6;
    resize: none;
    font-family: inherit;
}
textarea:focus {
    border-color: #3b82f6;
    outline: none;
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.2);
}

/* --- ボタンエリア (修正版) --- */
.action-area {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid #1e293b;
}

/* メインボタン (変換実行) */
.card-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.8rem 2rem;
    background: transparent;
    color: #3b82f6;
    font-size: 0.9rem;
    font-weight: 600;
    border: 1px solid #3b82f6;
    transition: all 0.2s ease;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    cursor: pointer;
}
.card-link:hover {
    background: #3b82f6;
    color: #ffffff;
    box-shadow: 0 0 15px rgba(59, 130, 246, 0.5);
}

/* セカンダリボタン (コピー・クリア) */
.text-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.8rem 1.5rem;
    background: rgba(30, 41, 59, 0.3);
    color: #94a3b8;
    font-size: 0.85rem;
    font-weight: 500;
    border: 1px solid #334155;
    transition: all 0.2s ease;
    cursor: pointer;
}
.text-link:hover {
    border-color: #60a5fa;
    color: #f8fafc;
    background: rgba(59, 130, 246, 0.1);
}
#reset-btn:hover {
    border-color: #ef4444;
    color: #f87171;
    background: rgba(239, 68, 68, 0.1);
}

/* --- SEOコンテンツエリア (App 1/2と統一) --- */
.seo-content-area {
    max-width: 900px;
    margin: 4rem auto 0;
    color: #cbd5e1;
    text-align: left;
}
.seo-content-area h2 {
    font-size: 1.5rem;
    color: #f8fafc;
    border-left: 4px solid #3b82f6;
    padding-left: 1rem;
    margin-bottom: 1.5rem;
}
.seo-content-area p {
    line-height: 1.8;
    margin-bottom: 2rem;
    font-size: 0.95rem;
}
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}
.feature-card {
    background: rgba(15, 23, 42, 0.4);
    border: 1px solid #334155;
    padding: 1.5rem;
    transition: all 0.3s ease;
}
.feature-card:hover {
    border-color: #3b82f6;
    background: rgba(59, 130, 246, 0.05);
}
.feature-card h3 {
    color: #60a5fa;
    margin-bottom: 0.8rem;
    font-size: 1.1rem;
}
.feature-card p {
    margin-bottom: 0;
    font-size: 0.9rem;
    color: #94a3b8;
}