/* =========================================
   VOM Lab - Common Styles
   Base styles shared across all pages
   ========================================= */

/* =========================================
   1. CSS Variables & Reset
   ========================================= */
:root {
    --bg-color: #FFFFFF;
    --text-primary: #0A1931;
    --text-secondary: #546e7a;
    --accent-color: #007AFF;
    --light-bg: #F9FAFB;
    --border-color: #eaeaea;
    --section-spacing: 120px;
    
    /* Additional colors for components */
    --tag-bg: #e3f2fd;
    --tag-text: #007AFF;
    --tag-journal-bg: #e8f5e9;
    --tag-journal-text: #2e7d32;
    --active-bg: #e3f2fd;
    --keyword-bg: #f1f3f5;
}

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

html {
    scroll-behavior: smooth;
    /* 스크롤바 공간을 항상 확보하여 페이지 전환 시 레이아웃 밀림 방지 */
    scrollbar-gutter: stable;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    font-weight: 400;
}

a { 
    text-decoration: none; 
    color: var(--text-primary); 
    transition: color 0.2s ease; 
}

a:hover { 
    color: var(--accent-color); 
}

ul { 
    list-style: none; 
}

img {
    max-width: 100%;
    height: auto;
}

/* =========================================
   2. Layout & Common Utilities
   ========================================= */
.container { 
    width: 90%; 
    max-width: 1200px; 
    margin: 0 auto; 
}

.container-narrow {
    width: 90%;
    max-width: 1000px;
    margin: 0 auto;
}

section { 
    padding: var(--section-spacing) 0; 
}

.section-header { 
    margin-bottom: 30px; 
}

.section-title { 
    font-size: 2rem; 
    font-weight: 700; 
    margin-bottom: 16px; 
}

.section-label {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 40px;
    border-left: 4px solid var(--accent-color);
    padding-left: 16px;
}

/* =========================================
   3. Buttons
   ========================================= */
.btn-primary {
    display: inline-block; 
    padding: 16px 32px; 
    background-color: var(--accent-color);
    color: white !important; 
    font-weight: 600; 
    border-radius: 4px;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.btn-primary:hover { 
    background-color: #0062cc; 
    transform: translateY(-2px); 
}

/* =========================================
   4. Header / Navigation
   ========================================= */
header {
    height: 80px;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: sticky; 
    top: 0; 
    z-index: 1000;
    display: flex; 
    align-items: center;
}

header .container { 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
}

.logo { 
    font-size: 1.6rem; 
    font-weight: 800; 
    color: var(--text-primary); 
    white-space: nowrap;
    text-decoration: none;
}

.logo span { 
    color: var(--accent-color); 
}

.nav-links { 
    display: flex; 
    gap: 40px; 
}

.nav-links a {
    font-size: 0.9rem; 
    font-weight: 600; 
    text-transform: uppercase; 
    letter-spacing: 0.5px;
    color: var(--text-primary);
    text-decoration: none;
}

.nav-links a:hover,
.nav-links a.active { 
    color: var(--accent-color); 
}

/* Mobile Menu Button (hidden by default) */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
    z-index: 1001;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: all 0.3s ease;
}

/* Hamburger to X animation */
.mobile-menu-btn.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* =========================================
   5. Footer
   ========================================= */
footer {
    padding: 60px 0; 
    background-color: #fff; 
    text-align: center;
    color: var(--text-secondary); 
    font-size: 0.9rem; 
    border-top: 1px solid var(--border-color);
}

footer p {
    line-height: 1.8;
}

/* =========================================
   6. Page Header (for sub-pages)
   ========================================= */
.page-header {
    padding: 80px 0 60px;
    text-align: center;
}

.page-title { 
    font-size: 2.5rem; 
    font-weight: 700; 
    margin-bottom: 10px; 
}

.page-desc { 
    color: var(--text-secondary); 
    font-size: 1rem;
    max-width: 600px;
    margin: 0 auto;
}

/* =========================================
   7. Common Component Styles
   ========================================= */

/* Tags / Badges */
.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 600;
}

.badge-primary {
    background-color: var(--tag-bg);
    color: var(--tag-text);
}

.badge-success {
    background-color: var(--tag-journal-bg);
    color: var(--tag-journal-text);
}

.badge-gray {
    background-color: #f1f3f5;
    color: #495057;
}

.badge-active {
    background-color: var(--active-bg);
    color: var(--accent-color);
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
}

/* Keyword Tags */
.keyword {
    background-color: var(--keyword-bg);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    color: #495057;
}

.keyword-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

/* Cards */
.card {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.05);
    border-color: transparent;
}

/* Light background section */
.bg-light {
    background-color: var(--light-bg);
}

/* =========================================
   8. Responsive Media Queries
   ========================================= */

/* Tablet (Max 900px) */
@media (max-width: 900px) {
    :root {
        --section-spacing: 80px;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .page-title {
        font-size: 2rem;
    }
}

/* Tablet & Mobile Menu (Max 1020px) */
@media (max-width: 1020px) {
    .nav-links { 
        display: none;
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(10px);
        -webkit-backdrop-filter: blur(10px);
        flex-direction: column;
        padding: 20px 0;
        gap: 0;
        border-bottom: 1px solid var(--border-color);
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    }
    
    .nav-links.mobile-open {
        display: flex;
    }
    
    .nav-links a {
        padding: 15px 30px;
        border-bottom: 1px solid var(--border-color);
        width: 100%;
        text-align: center;
    }
    
    .nav-links a:last-child {
        border-bottom: none;
    }
    
    .nav-links a:hover,
    .nav-links a.active {
        background-color: var(--light-bg);
    }
    
    .mobile-menu-btn {
        display: flex;
    }
}

/* Mobile (Max 768px) */
@media (max-width: 768px) {
    :root {
        --section-spacing: 60px;
    }
    
    .container {
        width: 92%;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .page-header {
        padding: 60px 0 40px;
    }
    
    .page-title {
        font-size: 1.75rem;
    }
    
    footer {
        padding: 40px 0;
    }
}

/* Small Mobile (Max 480px) */
@media (max-width: 480px) {
    .logo {
        font-size: 1.4rem;
    }
    
    .page-title {
        font-size: 1.5rem;
    }
}