:root {
    --primary-color: #2c3e50;
    --secondary-color: #e74c3c;
    --sidebar-bg: #1a252f;
    --sidebar-hover: #34495e;
    --bg-color: #f0f2f5;
    --card-bg: #ffffff;
    --text-color: #333;
    --text-muted: #666;
    --sidebar-width: 260px;
    --header-height: 120px;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    min-height: 100vh;
}

.app-container {
    display: flex;
    width: 100%;
}

/* Sidebar Styling */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--sidebar-bg);
    color: white;
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    z-index: 100;
    transition: transform 0.3s ease;
}

.sidebar-header {
    padding: 2rem 1.5rem;
    text-align: center;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.sidebar-header h2 {
    margin: 0;
    font-size: 1.5rem;
    letter-spacing: 1px;
    color: var(--secondary-color);
}

.sidebar-nav {
    flex-grow: 1;
    padding: 1rem 0;
}

.sidebar-nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.sidebar-nav li {
    padding: 1rem 1.5rem;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    font-size: 1.1rem;
    opacity: 0.8;
}

.sidebar-nav li i {
    margin-right: 12px;
    width: 20px;
    text-align: center;
}

.sidebar-nav li:hover {
    background-color: var(--sidebar-hover);
    opacity: 1;
}

.sidebar-nav li.active {
    background-color: var(--secondary-color);
    opacity: 1;
    font-weight: bold;
}

.sidebar-footer {
    padding: 1.5rem;
    font-size: 0.85rem;
    text-align: center;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.sidebar-footer a {
    color: rgba(255,255,255,0.6);
    text-decoration: none;
}

/* Content Area Styling */
.content-area {
    margin-left: var(--sidebar-width);
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.top-header {
    background-color: white;
    padding: 2rem 3rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.top-header h1 {
    margin: 0;
    color: var(--primary-color);
    font-size: 2rem;
}

.top-header p {
    margin: 0.5rem 0 0;
    color: var(--text-muted);
}

#main-view {
    padding: 2rem 3rem;
    flex-grow: 1;
}

.view-section {
    display: none;
    animation: fadeIn 0.4s ease;
}

.view-section.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.6rem;
}

/* Specific Component Styling */
.trend-list {
    background: white;
    padding: 1.5rem 2rem 1.5rem 3.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

.trend-list li {
    padding: 1rem 0;
    border-bottom: 1px solid #eee;
    font-size: 1.2rem;
}

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

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.trend-article {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    position: relative;
}

.article-badge {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    background: var(--bg-color);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: bold;
    color: var(--secondary-color);
}

.trend-article h3 {
    margin-top: 0;
    color: var(--primary-color);
}

.read-more {
    background: none;
    border: 1px solid var(--secondary-color);
    color: var(--secondary-color);
    padding: 8px 16px;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
    margin-top: 1rem;
    transition: all 0.2s;
}

.read-more:hover {
    background: var(--secondary-color);
    color: white;
}

.image-placeholder {
    width: 100%;
    height: 300px;
    background: linear-gradient(135deg, #2c3e50, #e74c3c);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
    font-weight: bold;
    margin-top: 2rem;
}

/* Footer */
.main-footer {
    padding: 2rem 3rem;
    background: #f8f9fa;
    text-align: center;
    border-top: 1px solid #ddd;
}

/* Contact Form Styling */
.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    margin-top: 1.5rem;
    max-width: 600px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-weight: bold;
    color: var(--primary-color);
}

.form-group input, 
.form-group select, 
.form-group textarea {
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-family: inherit;
    font-size: 1rem;
}

.form-group input:focus, 
.form-group textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 2px rgba(231, 76, 60, 0.1);
}

.submit-btn {
    background-color: var(--secondary-color);
    color: white;
    padding: 1rem;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.2s;
    align-self: flex-start;
    min-width: 150px;
}

.submit-btn:hover {
    background-color: #c0392b;
}

/* Mobile Responsiveness */
@media (max-width: 900px) {
    .sidebar {
        transform: translateX(-100%);
    }
    
    .content-area {
        margin-left: 0;
    }
    
    .top-header, #main-view {
        padding: 1.5rem;
    }
}