/* 
 * 
 * : + 
 * : , , 
 */

/* ============================================
   (CSS Variables)
   ============================================ */
:root {
    
    --primary-blue: #11457E;
    --light-blue: #1a5ba8;
    --bg-blue: #e8f0f9;
    --dark-blue: #0d3560;
    
    
    --white: #FFFFFF;
    --text-dark: #333333;
    --text-gray: #64748B;
    --border-gray: #DEE2E6;
    --bg-light: #F8F9FA;
    
    
    --warning-yellow: #FFF3CD;
    --warning-border: #FFC107;
    --success-green: #D4EDDA;
    --success-border: #28A745;
    
    
    --container-width: 1200px;
    --content-width: 900px;
    --sidebar-width: 280px;
    
    
    --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-heading: "Segoe UI", Arial, sans-serif;
}

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

body {
    font-family: var(--font-main);
    font-size: 16px;
    line-height: 1.8;
    color: var(--text-dark);
    background: var(--white);
}

/* ============================================
   
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    color: var(--dark-blue);
    font-weight: 600;
    margin-top: 1.5em;
    margin-bottom: 0.75em;
    line-height: 1.3;
}

h1 {
    font-size: 2.5em;
    color: var(--primary-blue);
    border-bottom: 3px solid var(--primary-blue);
    padding-bottom: 15px;
    margin-bottom: 30px;
}

h2 {
    font-size: 2em;
    border-bottom: 2px solid var(--border-gray);
    padding-bottom: 10px;
    margin-top: 50px;
}

h3 {
    font-size: 1.5em;
    color: var(--primary-blue);
}

h4 {
    font-size: 1.25em;
    color: var(--text-dark);
}

p {
    margin-bottom: 1.2em;
}

strong {
    font-weight: 600;
    color: var(--primary-blue);
}

a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--light-blue);
    text-decoration: underline;
}

/* ============================================
   LAYOUT - 
   ============================================ */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 20px;
}

.content-wrapper {
    display: grid;
    grid-template-columns: 1fr var(--sidebar-width);
    gap: 40px;
    margin-top: 30px;
}

.main-content {
    min-width: 0; 
}

/* ============================================
   HEADER ()
   ============================================ */
header {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--light-blue) 100%);
    color: var(--white);
    padding: 30px 0;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

header .logo {
    font-size: 1.8em;
    font-weight: 700;
}


.main-menu {
    background: var(--bg-light);
    border-bottom: 2px solid var(--border-gray);
    padding: 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.main-menu ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 10px;
    padding: 0;
    margin: 0;
}

.main-menu li {
    margin: 0;
}

.main-menu a {
    display: block;
    padding: 15px 20px;
    color: var(--primary-blue);
    font-weight: 500;
    transition: all 0.3s ease;
}

.main-menu a:hover {
    background: var(--primary-blue);
    color: var(--white);
    text-decoration: none;
}

/* ============================================
   BREADCRUMBS ()
   ============================================ */
.breadcrumbs {
    padding: 15px 0;
    font-size: 14px;
    color: var(--text-gray);
}

.breadcrumbs a {
    color: var(--text-gray);
}

.breadcrumbs a:hover {
    color: var(--primary-blue);
}

.breadcrumbs span {
    color: var(--text-dark);
}

/* ============================================
   TABLE OF CONTENTS ()
   ============================================ */
.table-of-contents {
    background: var(--bg-light);
    border: 2px solid var(--border-gray);
    border-radius: 8px;
    padding: 25px;
    margin: 30px 0;
}

.table-of-contents h2 {
    margin-top: 0;
    border: none;
    padding: 0;
    font-size: 1.5em;
}

.table-of-contents ul {
    list-style: none;
    padding-left: 0;
}

.table-of-contents ul ul {
    padding-left: 20px;
    margin-top: 8px;
}

.table-of-contents li {
    margin-bottom: 8px;
}

.table-of-contents a {
    font-size: 16px;
}

/* ============================================
   
   ============================================ */
.tip-box, .warning-box, .success-box, .info-box {
    padding: 20px;
    margin: 25px 0;
    border-radius: 6px;
    border-left: 5px solid;
}


.tip-box {
    background: var(--bg-blue);
    border-left-color: var(--primary-blue);
}


.warning-box {
    background: var(--warning-yellow);
    border-left-color: var(--warning-border);
}


.success-box {
    background: var(--success-green);
    border-left-color: var(--success-border);
}


.info-box {
    background: var(--bg-light);
    border-left-color: var(--text-gray);
}

/* ============================================
   CTA ()
   ============================================ */
.cta-inline, .cta-main {
    background: linear-gradient(135deg, var(--primary-blue), var(--light-blue));
    color: var(--white);
    padding: 30px;
    margin: 40px 0;
    border-radius: 8px;
    text-align: center;
}

.cta-main {
    padding: 40px;
    box-shadow: 0 4px 20px rgba(0, 86, 179, 0.2);
}

.cta-inline h3, .cta-main h2, .cta-main h3 {
    color: var(--white);
    margin-top: 0;
    border: none;
    padding: 0;
}

.btn-primary, .btn-secondary {
    display: inline-block;
    padding: 15px 35px;
    margin: 10px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 6px;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
}

.btn-primary {
    background: var(--white);
    color: var(--primary-blue);
}

.btn-primary:hover {
    background: var(--bg-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

.btn-secondary {
    background: transparent;
    color: var(--white);
    border: 2px solid var(--white);
}

.btn-secondary:hover {
    background: var(--white);
    color: var(--primary-blue);
}

/* ============================================
   
   ============================================ */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 25px 0;
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

th {
    background: var(--bg-blue);
    color: var(--primary-blue);
    padding: 15px;
    text-align: left;
    font-weight: 600;
    border-bottom: 2px solid var(--primary-blue);
}

td {
    padding: 12px 15px;
    border-bottom: 1px solid var(--border-gray);
}

tr:hover {
    background: var(--bg-light);
}

/* ============================================
   
   ============================================ */
ul, ol {
    margin: 15px 0 15px 30px;
}

li {
    margin-bottom: 10px;
    line-height: 1.8;
}

/* ============================================
   
   ============================================ */
.image-container {
    text-align: center;
    margin: 30px 0;
}

.image-container img {
    max-width: 100%;
    height: auto;
    border: 1px solid var(--border-gray);
    border-radius: 6px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.image-caption {
    margin-top: 10px;
    font-size: 14px;
    font-style: italic;
    color: var(--text-gray);
}

/* ============================================
   
   ============================================ */
.related-articles {
    background: var(--bg-light);
    padding: 30px;
    margin: 50px 0;
    border-radius: 8px;
}

.related-articles h3 {
    color: var(--primary-blue);
    margin-top: 0;
}

.article-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.article-card {
    background: var(--white);
    border: 1px solid var(--border-gray);
    border-radius: 6px;
    padding: 20px;
    transition: all 0.3s ease;
}

.article-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0, 86, 179, 0.15);
    border-color: var(--primary-blue);
}

.article-card h4 {
    margin-top: 0;
    font-size: 1.1em;
}

.article-card p {
    font-size: 14px;
    color: var(--text-gray);
}

/* ============================================
   SIDEBAR ()
   ============================================ */
.sidebar {
    position: sticky;
    top: 80px;
    height: fit-content;
}

.widget {
    background: var(--bg-light);
    padding: 20px;
    margin-bottom: 25px;
    border-radius: 8px;
    border: 1px solid var(--border-gray);
}

.widget h3 {
    margin-top: 0;
    font-size: 1.2em;
    color: var(--primary-blue);
}

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

.widget li {
    margin-bottom: 10px;
}

.widget a {
    color: var(--text-dark);
    font-size: 14px;
}

.widget a:hover {
    color: var(--primary-blue);
}


.widget-cta form input,
.widget-cta form button {
    width: 100%;
    padding: 10px;
    margin-bottom: 10px;
    border: 1px solid var(--border-gray);
    border-radius: 4px;
    font-size: 14px;
}

.widget-cta form button {
    background: var(--primary-blue);
    color: var(--white);
    border: none;
    cursor: pointer;
    font-weight: 600;
}

.widget-cta form button:hover {
    background: var(--light-blue);
}

/* ============================================
   FOOTER ()
   ============================================ */
footer {
    background: var(--bg-light);
    border-top: 2px solid var(--border-gray);
    padding: 40px 0 20px 0;
    margin-top: 80px;
    text-align: center;
    color: var(--text-gray);
}

/* ============================================
   (Mobile)
   ============================================ */
@media (max-width: 1024px) {
    .content-wrapper {
        grid-template-columns: 1fr;
    }
    
    .sidebar {
        position: static;
        margin-top: 40px;
    }
}

@media (max-width: 768px) {
    :root {
        --container-width: 100%;
    }
    
    body {
        font-size: 15px;
    }
    
    h1 {
        font-size: 2em;
    }
    
    h2 {
        font-size: 1.6em;
    }
    
    h3 {
        font-size: 1.3em;
    }
    
    .main-menu ul {
        flex-direction: column;
        gap: 0;
    }
    
    .main-menu a {
        padding: 12px 20px;
        border-bottom: 1px solid var(--border-gray);
    }
    
    .article-grid {
        grid-template-columns: 1fr;
    }
    
    
    .table-responsive {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    h1 {
        font-size: 1.75em;
    }
    
    .cta-inline, .cta-main {
        padding: 20px;
    }
    
    .btn-primary, .btn-secondary {
        display: block;
        width: 100%;
        margin: 10px 0;
    }
}

/* ============================================
   UTILITY 
   ============================================ */
.text-center {
    text-align: center;
}

.mt-40 {
    margin-top: 40px;
}

.mb-40 {
    margin-bottom: 40px;
}


.internal-link {
    background: var(--bg-blue);
    padding: 15px;
    margin: 20px 0;
    border-left: 4px solid var(--primary-blue);
    border-radius: 4px;
}

.internal-link::before {
    content: "📖 ";
}


.case-study {
    background: var(--success-green);
    padding: 20px;
    margin: 25px 0;
    border-left: 4px solid var(--success-border);
    border-radius: 6px;
}

.case-study h4 {
    margin-top: 0;
    color: #155724;
}


.analogy-box {
    background: var(--bg-blue);
    padding: 20px;
    margin: 20px 0;
    border-radius: 6px;
    border-left: 4px solid var(--light-blue);
}

.analogy-box::before {
    content: "💡 ";
    font-size: 1.5em;
}

/* ============================================
   
   ============================================ */
@media print {
    .main-menu, .sidebar, .cta-inline, .cta-main, .related-articles {
        display: none;
    }
    
    body {
        font-size: 12pt;
        color: #000;
        background: #fff;
    }
    
    h1, h2, h3 {
        color: #000;
        page-break-after: avoid;
    }
    
    a {
        color: #000;
        text-decoration: underline;
    }
}