* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Smooth scrolling for page jumps */
html {
    scroll-behavior: smooth;
}

body {
    background-color: #f4f7f6;
    color: #333;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Top Navigation Header */
header {
    background-color: #182848;
    color: #ffffff;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.15);
}

.header-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    max-width: 900px;
    margin: 0 auto;
}

.header-title h1 {
    font-size: 20px;
    margin-bottom: 2px;
}

.header-title p {
    font-size: 12px;
    color: #a0aec0;
}

/* Burger Icon Styling */
.burger-icon {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    width: 28px;
    height: 20px;
    cursor: pointer;
    background: transparent;
    border: none;
    padding: 0;
    z-index: 1001;
}

.burger-icon span {
    width: 100%;
    height: 3px;
    background-color: #ffffff;
    border-radius: 2px;
    transition: all 0.3s ease;
}

/* Burger Animation when active */
.burger-icon.active span:nth-child(1) {
    transform: translateY(8.5px) rotate(45deg);
}

.burger-icon.active span:nth-child(2) {
    opacity: 0;
}

.burger-icon.active span:nth-child(3) {
    transform: translateY(-8.5px) rotate(-45deg);
}

/* Slide-down Nav Drawer */
.nav-menu {
    display: none;
    background-color: #111d35;
    border-top: 1px solid #233554;
    max-width: 900px;
    margin: 0 auto;
}

.nav-menu.open {
    display: block;
}

.nav-menu ul {
    list-style: none;
    padding: 10px 0;
}

.nav-menu li a {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    color: #e2e8f0;
    text-decoration: none;
    font-size: 16px;
    font-weight: 500;
    transition: background 0.2s ease;
}

.nav-menu li a:hover {
    background-color: #1e2d4a;
    color: #ffffff;
}

/* Main App Container */
.app-container {
    max-width: 900px;
    width: 100%;
    margin: 20px auto;
    padding: 0 15px;
    flex: 1;
}

/* 3-Menu Navigation Grid */
.menu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.menu-card {
    background: #ffffff;
    border-radius: 12px;
    padding: 25px 20px;
    text-align: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.menu-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.menu-card.active {
    border-color: #4b6cb7;
    background-color: #f0f4ff;
}

.menu-icon {
    font-size: 40px;
    margin-bottom: 12px;
}

.menu-title {
    font-size: 20px;
    font-weight: bold;
    color: #182848;
    margin-bottom: 6px;
}

.menu-subtitle {
    font-size: 13px;
    color: #666;
}

/* Dynamic Content Body Area */
.content-area {
    background: #ffffff;
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    min-height: 350px;
    scroll-margin-top: 80px;
}

.section-content {
    display: none;
}

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

.section-heading {
    font-size: 20px;
    color: #182848;
    margin-bottom: 10px;
    border-bottom: 2px solid #edf2f7;
    padding-bottom: 8px;
}

/* Styled Links */
.link-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 15px;
}

.url-link {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: #f8f9fa;
    border: 1px solid #e2e8f0;
    padding: 14px 18px;
    border-radius: 8px;
    color: #182848;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s ease;
}

.url-link:hover {
    background-color: #4b6cb7;
    color: #ffffff;
    border-color: #4b6cb7;
    transform: translateX(4px);
}

.url-link::after {
    content: "🔗";
    font-size: 14px;
}

/* Responsive YouTube Video Grid */
.video-grid {
    display: flex;
    flex-direction: column;
    gap: 25px;
    margin-top: 20px;
}

.video-card {
    background: #fafafa;
    border: 1px solid #e2e8f0;
    border-radius: 10px;
    padding: 15px;
}

.video-title {
    font-size: 16px;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 10px;
}

.video-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 Aspect Ratio */
    height: 0;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}
.card {
            background: #ffffff;
            padding: 15px;
            border-radius: 8px;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
            width: 100%;            /* Fills the column width */
            box-sizing: border-box;
            text-align: center;
        }

.card img {
            width: 100%;
            height: auto;
            border-radius: 4px;
            display: block;
        }
.single-column-container {
            display: flex;
            flex-direction: column; /* Stacks items vertically */
            align-items: center;    /* Centers cards horizontally */
            gap: 10px;              /* Space between rows */
            max-width: 800px;       /* Limits the column width */
            margin: 0 auto;         /* Centers the entire container on the page */
        }
/* Footer Styling */
footer {
    background-color: #182848;
    color: #a0aec0;
    text-align: center;
    padding: 20px 10px;
    margin-top: 40px;
    font-size: 14px;
}

footer p {
    margin: 0;
}

footer span {
    color: #ffffff;
    font-weight: 600;
}