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

h1 {
    margin: 0 0 12px 0;
    line-height: 1.2;
}

.header-links {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 12px;
    font-size: 0.9rem;
    color: var(--text-sub);
}

.nav-link {
    text-decoration: none;
    color: var(--text-sub);
    transition: color 0.2s, transform 0.2s;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.nav-link.usage:hover {
    color: var(--primary-hover);
    transform: translateY(-1px);
}

.nav-link.credit:hover {
    color: var(--text-main);
    text-decoration: underline;
}

.separator {
    color: var(--border-color);
    font-size: 0.8rem;
}

.nav-link .icon {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background-color: var(--border-color);
    color: #fff;
    font-size: 0.7rem;
    font-weight: bold;
    transition: background-color 0.2s;
}

.nav-link.usage:hover .icon {
    background-color: var(--primary-hover);
}

.hero-description {
    color: var(--text-sub);
    font-size: 0.9rem;
    margin: -8px 0 20px 0;
    line-height: 1.6;
    font-weight: 500;
}

.restart-info {
    color: var(--text-sub);
    font-size: 0.8rem;
    margin: 10px auto;
    text-align: right;
    max-width: 600px;
    width: 90%;
    line-height: 1.6;
}

.history-section {
    width: 90%;
    max-width: 800px;
    margin: 0 auto 40px auto;
}

.history-section h2 {
    text-align: left;
    font-size: 1.2rem;
    margin: 0 0 12px 0;
    color: var(--text-main);
}

.history-box {
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    height: 200px;
    overflow-y: auto;
    box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
}
.history-item {
    display: flex;
    flex-direction: row;
    align-items: flex-start;
    border-bottom: 1px solid #f1f5f9;
    padding: 12px 0;
    gap: 16px;
}

.history-item:last-child {
    border-bottom: none;
}

.history-meta {
    display: flex;
    align-items: center;
    gap: 8px;
    width: 140px;
    flex-shrink: 0;
}

.history-date {
    color: var(--text-sub);
    font-weight: 600;
    font-family: monospace;
    font-size: 0.9rem;
}

.version-badge {
    background-color: #f3f4f6;
    border: 1px solid #d1d5db;
    color: #4b5563;
    font-size: 0.75rem;
    padding: 1px 6px;
    border-radius: 10px;
    font-weight: 700;
}

.history-content {
    color: var(--text-main);
    line-height: 1.5;
    flex: 1;
}

@media (max-width: 768px) {
    body {
        padding-left: 16px;
        padding-right: 16px;
    }

    .main-header {
        margin-top: 30px;
        margin-bottom: 30px;
    }
    
    h1 {
        font-size: 1.5rem;
    }

    .hero-description {
        font-size: 0.85rem;
        margin-bottom: 16px;
    }
    .history-item {
        flex-direction: column;
        gap: 4px;
        padding: 10px 0;
    }

    .history-meta {
        width: 100%;
        margin-bottom: 2px;
    }

    .history-date {
        font-size: 0.8rem;
    }

    .history-content {
        font-size: 0.9rem;
        padding-left: 2px;
    }
}