/* Main Stylesheet: Desktop-first layout */

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

body {
    font-family: var(--font-sans);
    color: var(--kbr-dark-gray);
    background-color: var(--kbr-white);
    line-height: 1.6;
    font-size: 18px;
}

/* Header: Dark background, centered title only */
.header {
    background-color: var(--kbr-black);
    color: var(--kbr-white);
    padding: 0 30px;
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
}

.header-title {
    font-size: 20px;
    font-family: var(--font-heading);
    font-weight: 500;
    text-align: center;
}

.hamburger-btn {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    gap: 5px;
}

.hamburger-btn span {
    width: 25px;
    height: 3px;
    background-color: var(--kbr-white);
    transition: var(--transition-normal);
    border-radius: 2px;
}

/* Main container: Flex layout with sidebar + content */
.main-container {
    display: flex;
    min-height: calc(100vh - var(--header-height));
}

/* Sidebar: Sticky navigation (desktop only) */
.sidebar {
    width: var(--sidebar-width);
    background-color: #E5E3D7;
    border-right: 1px solid #E5E3D7;
    padding: 30px 0;
    position: sticky;
    top: var(--header-height);
    overflow-y: auto;
    max-height: calc(100vh - var(--header-height));
}

.nav-list {
    list-style: none;
}

.nav-section {
    padding: 0 20px 20px 20px;
    border-bottom: 1px solid #E5E3D7;
}

.section-title {
    display: block;
    font-size: 16px;
    font-family: var(--font-heading);
    font-weight: 500;
    color: var(--kbr-dark-green);
    text-transform: uppercase;
    margin-bottom: 10px;
    letter-spacing: 0.5px;
}

.nav-subsection {
    list-style: none;
}

.nav-subsection li {
    margin-bottom: 8px;
}

.nav-link {
    text-decoration: none;
    color: var(--kbr-dark-gray);
    font-size: 15px;
    display: block;
    padding: 8px 10px;
    border-radius: 4px;
    transition: var(--transition-fast);
}

.nav-link:hover {
    background-color: var(--kbr-light-gray);
    color: var(--kbr-dark-green);
}

.nav-link.active {
    background-color: #595959;
    color: var(--kbr-white);
    font-weight: 600;
}

/* Content area: Main content with iframe container */
.content-area {
    flex: 1;
    padding: 40px;
    overflow-y: auto;
    background-color: #D6D3C6;
}

.page-content {
    max-width: 1200px;
    margin: 0 auto;
}

/* Page heading styles */
.page-content h1 {
    font-size: 40px;
    font-family: var(--font-heading);
    color: var(--kbr-dark-green);
    margin-bottom: 20px;
    font-weight: 500;
}

.page-content h2 {
    font-size: 23px;
    font-family: var(--font-heading);
    color: var(--kbr-dark-green);
    margin-top: 30px;
    margin-bottom: 15px;
    font-weight: 500;
}

.page-content h3 {
    display: none;
}

/* Body text styling */
.page-content p {
    font-size: 18px;
    line-height: 1.8;
    margin-bottom: 15px;
    color: var(--kbr-dark-gray);
}

/* Chart container with iframe */
.chart-container {
    margin: 40px 0;
    border-radius: 4px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.chart-container iframe {
    width: 100%;
    height: 600px;
    border: none;
    display: block;
}

/* Chart description below iframe */
.chart-description {
    padding: 20px;
    background-color: #E5E3D7;
}

.chart-description h3 {
    font-size: 23px;
    font-family: var(--font-heading);
    color: var(--kbr-dark-green);
    margin-bottom: 12px;
    font-weight: 500;
}

.chart-description p {
    font-size: 18px;
    line-height: 1.7;
    color: var(--kbr-dark-gray);
}

/* Page banner: image-ready with color fallback */
.page-banner {
    width: calc(100vw - var(--sidebar-width));
    position: relative;
    left: 50%;
    transform: translateX(-50%);
    margin-top: -40px;
    margin-bottom: 40px;
    overflow: hidden;
    line-height: 0;
}

.page-banner img {
    width: 100%;
    height: auto;
    display: block;
}

/* Footer: Dark background matching header */
.footer {
    background-color: var(--kbr-black);
    color: var(--kbr-white);
    padding: 30px;
    text-align: center;
    font-size: 14px;
    line-height: 1.8;
}

.footer p {
    color: var(--kbr-white);
    margin: 5px 0;
}

.footer small {
    opacity: 0.8;
}