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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    margin-bottom: 20px;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #1a1a1a;
    margin-bottom: 15px;
}

.meta-info {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9rem;
    color: #666;
}

.date {
    color: #666;
}

.separator {
    color: #ccc;
}

.read-time {
    color: #666;
}

.category {
    background-color: #fff3cd;
    padding: 4px 12px;
    border-radius: 4px;
    color: #856404;
}

/* Hero Image */
.hero-image {
    width: 100%;
    height: 400px;
    margin-bottom: 30px;
    border-radius: 8px;
    overflow: hidden;
}

.hero-image img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

/* Content Wrapper */
.content-wrapper {
    display: flex;
    gap: 30px;
    align-items: flex-start;
}

/* Sidebar */
.sidebar {
    flex: 0 0 350px;
    position: sticky;
    top: 20px;
}

.summary-box {
    background-color: #f0f4f8;
    border-radius: 8px;
    overflow: hidden;
}

.summary-header {
    background-color: #f0f4f8;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.summary-header h2 {
    font-size: 1.3rem;
    font-weight: 700;
    color: #1a1a1a;
}

.toggle-icon {
    font-size: 1rem;
    color: #666;
    transition: transform 0.3s ease;
}

.toggle-icon.rotated {
    transform: rotate(180deg);
}

.summary-nav {
    padding: 10px 0;
}

.nav-item {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    padding: 15px 20px;
    text-decoration: none;
    color: #333;
    transition: background-color 0.2s ease;
}

.nav-item:hover {
    background-color: #e1e8f0;
}

.nav-item .number {
    font-weight: 700;
    color: #0066cc;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.nav-item .text {
    flex: 1;
    line-height: 1.5;
}

/* Main Content */
.main-content {
    flex: 1;
    background-color: white;
    padding: 40px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

/* Info Box */
.info-box {
    background-color: #d1ecf1;
    border-left: 4px solid #0c5460;
    padding: 20px 25px;
    margin-bottom: 30px;
    border-radius: 4px;
}

.info-box h3 {
    font-size: 1.2rem;
    font-weight: 700;
    color: #0c5460;
    margin-bottom: 15px;
}

.info-box ul {
    list-style: none;
    padding-left: 0;
}

.info-box ul li {
    margin-bottom: 12px;
    padding-left: 25px;
    position: relative;
}

.info-box ul li:before {
    content: "●";
    position: absolute;
    left: 0;
    color: #0c5460;
    font-size: 1.2rem;
}

.highlight-box {
    background-color: #d4edda;
    border-left-color: #155724;
}

.highlight-box h3 {
    color: #155724;
}

.highlight-box ul li:before {
    color: #155724;
}

/* Intro Section */
.intro-section {
    margin-bottom: 30px;
    font-size: 1.05rem;
    line-height: 1.8;
}

/* Sections */
section {
    margin-bottom: 40px;
}

section h2 {
    font-size: 1.8rem;
    font-weight: 700;
    color: #1a1a1a;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.section-number {
    color: #0066cc;
}

section h3 {
    font-size: 1.3rem;
    font-weight: 700;
    color: #1a1a1a;
    margin-top: 25px;
    margin-bottom: 15px;
}

section p {
    margin-bottom: 15px;
    line-height: 1.8;
}

section ul {
    margin-bottom: 20px;
    padding-left: 0;
    list-style: none;
}

section ul li {
    margin-bottom: 12px;
    padding-left: 25px;
    position: relative;
    line-height: 1.7;
}

section ul li:before {
    content: "●";
    position: absolute;
    left: 0;
    color: #0066cc;
    font-size: 1.2rem;
}

/* Tip Box */
.tip-box {
    background-color: #fff3cd;
    border-left: 4px solid #856404;
    padding: 15px 20px;
    margin: 20px 0;
    border-radius: 4px;
}

.tip-box p {
    margin: 0;
    color: #856404;
}

/* Disclaimer */
.disclaimer {
    font-size: 0.9rem;
    color: #666;
    font-style: italic;
    margin-top: 30px;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .content-wrapper {
        flex-direction: column;
    }

    .sidebar {
        position: static;
        flex: 1;
        width: 100%;
        max-width: 100%;
    }

    .main-content {
        padding: 30px;
    }
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .hero-image {
        height: 250px;
    }

    .main-content {
        padding: 20px;
    }

    section h2 {
        font-size: 1.5rem;
    }

    .meta-info {
        flex-wrap: wrap;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.6rem;
    }

    .container {
        padding: 10px;
    }

    .main-content {
        padding: 15px;
    }
}