/* Auditory Frequency - Acoustic Physics & Tonotopic Bioacoustics */
:root {
    --fa-navy: #0c4a6e;
    --fa-navy-dark: #082f49;
    --fa-navy-light: #0284c7;
    --fa-amber: #d97706;
    --fa-amber-hover: #b45309;
    --fa-amber-soft: #fef3c7;
    --fa-bg: #f8fafc;
    --fa-card-bg: #ffffff;
    --fa-text: #0f172a;
    --fa-muted: #475569;
    --fa-border: #cbd5e1;
    --fa-shadow: 0 4px 20px rgba(12, 74, 110, 0.08);
    --fa-radius: 10px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--fa-bg);
    color: var(--fa-text);
    line-height: 1.7;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    color: var(--fa-navy-dark);
    line-height: 1.3;
    font-weight: 700;
}

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

a:hover {
    color: var(--fa-amber);
}

.fa-container {
    max-width: 1180px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.fa-topbar {
    background-color: var(--fa-navy-dark);
    color: #bae6fd;
    font-size: 13px;
    padding: 6px 0;
}

.fa-topbar-flex {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.fa-header {
    background-color: #ffffff;
    border-bottom: 2px solid var(--fa-border);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.fa-navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
}

.fa-logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.fa-logo-icon {
    width: 42px;
    height: 42px;
    background: linear-gradient(135deg, var(--fa-navy) 0%, var(--fa-amber) 100%);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #ffffff;
}

.fa-logo-title {
    font-size: 22px;
    font-weight: 800;
    color: var(--fa-navy-dark);
    letter-spacing: -0.5px;
}

.fa-logo-subtitle {
    font-size: 11px;
    color: var(--fa-amber);
    text-transform: uppercase;
    letter-spacing: 1.2px;
    font-weight: 600;
    display: block;
}

.fa-nav-menu {
    display: flex;
    list-style: none;
    gap: 22px;
    align-items: center;
}

.fa-nav-link {
    font-size: 15px;
    font-weight: 600;
    color: var(--fa-text);
    padding: 6px 12px;
    border-radius: 6px;
    transition: all 0.2s;
}

.fa-nav-link:hover, .fa-nav-link.active {
    color: var(--fa-navy);
    background-color: #e0f2fe;
}

.fa-nav-cta {
    background: linear-gradient(135deg, var(--fa-navy) 0%, var(--fa-amber) 100%);
    color: #ffffff !important;
    padding: 8px 18px;
    border-radius: 6px;
    font-weight: 600;
    font-size: 14px;
}

/* Hero */
.fa-hero {
    background: linear-gradient(180deg, #e0f2fe 0%, var(--fa-bg) 100%);
    padding: 60px 0 50px;
    border-bottom: 1px solid var(--fa-border);
}

.fa-hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 40px;
    align-items: center;
}

.fa-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: #ffffff;
    border: 1px solid var(--fa-border);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    color: var(--fa-navy);
    font-weight: 600;
    margin-bottom: 18px;
}

.fa-hero h1 {
    font-size: 38px;
    margin-bottom: 20px;
}

.fa-hero-lead {
    font-size: 18px;
    color: var(--fa-muted);
    margin-bottom: 28px;
    line-height: 1.6;
}

.fa-hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.fa-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 6px;
    font-weight: 600;
    font-size: 15px;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
}

.fa-btn-primary {
    background-color: var(--fa-navy);
    color: #ffffff;
}

.fa-btn-primary:hover {
    background-color: var(--fa-navy-light);
    color: #ffffff;
}

.fa-btn-secondary {
    background-color: #ffffff;
    color: var(--fa-navy);
    border: 1px solid var(--fa-border);
}

.fa-btn-secondary:hover {
    background-color: #f1f5f9;
}

.fa-hero-card {
    background-color: #ffffff;
    border-radius: var(--fa-radius);
    padding: 28px;
    border: 1px solid var(--fa-border);
    box-shadow: var(--fa-shadow);
}

.fa-hero-card h3 {
    font-size: 19px;
    margin-bottom: 14px;
    color: var(--fa-navy);
}

.fa-hero-card p {
    font-size: 14px;
    color: var(--fa-muted);
    margin-bottom: 16px;
}

/* Frequency Spectrum Analyzer Component */
.fa-spectrum-box {
    background: #ffffff;
    border-radius: var(--fa-radius);
    border: 1px solid var(--fa-border);
    padding: 32px;
    box-shadow: var(--fa-shadow);
    margin: 40px 0;
}

.fa-spec-header {
    text-align: center;
    margin-bottom: 24px;
}

.fa-spec-header h2 {
    font-size: 26px;
    margin-bottom: 8px;
}

.fa-spec-header p {
    color: var(--fa-muted);
    font-size: 15px;
}

.fa-spec-controls {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 24px;
}

.fa-band-btn {
    padding: 8px 16px;
    border: 1px solid var(--fa-border);
    background: #f8fafc;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    font-size: 14px;
    color: var(--fa-navy);
    transition: all 0.2s;
}

.fa-band-btn:hover, .fa-band-btn.active {
    background-color: var(--fa-navy);
    color: #ffffff;
    border-color: var(--fa-navy);
}

.fa-spec-display {
    background: #f0fdf4;
    border: 1px solid #bbf7d0;
    border-radius: 8px;
    padding: 24px;
}

.fa-spec-display-title {
    font-size: 18px;
    font-weight: 700;
    color: #166534;
    margin-bottom: 10px;
}

.fa-spec-display-text {
    font-size: 15px;
    color: #14532d;
    line-height: 1.6;
}

/* Grid & Cards */
.fa-section {
    padding: 50px 0;
}

.fa-section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 40px;
}

.fa-section-header h2 {
    font-size: 30px;
    margin-bottom: 12px;
}

.fa-section-header p {
    color: var(--fa-muted);
    font-size: 16px;
}

.fa-grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.fa-card {
    background-color: #ffffff;
    border-radius: var(--fa-radius);
    overflow: hidden;
    border: 1px solid var(--fa-border);
    box-shadow: 0 2px 12px rgba(12, 74, 110, 0.04);
    display: flex;
    flex-direction: column;
    transition: transform 0.2s, box-shadow 0.2s;
}

.fa-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 24px rgba(12, 74, 110, 0.08);
}

.fa-card-body {
    padding: 24px;
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.fa-tag {
    display: inline-block;
    padding: 4px 10px;
    background-color: #e0f2fe;
    color: var(--fa-navy);
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    border-radius: 4px;
    margin-bottom: 12px;
}

.fa-card h3 {
    font-size: 18px;
    margin-bottom: 12px;
    line-height: 1.4;
}

.fa-card p {
    font-size: 14px;
    color: var(--fa-muted);
    margin-bottom: 20px;
    flex-grow: 1;
    line-height: 1.6;
}

.fa-card-footer {
    padding-top: 14px;
    border-top: 1px solid #f1f5f9;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    color: var(--fa-muted);
}

/* Article Detail */
.fa-article-wrap {
    padding: 45px 0 60px;
}

.fa-article-grid {
    display: grid;
    grid-template-columns: 2.2fr 1fr;
    gap: 40px;
}

.fa-article-body {
    background-color: #ffffff;
    border-radius: var(--fa-radius);
    padding: 40px;
    border: 1px solid var(--fa-border);
    box-shadow: 0 2px 14px rgba(12, 74, 110, 0.03);
}

.fa-article-meta {
    display: flex;
    gap: 14px;
    align-items: center;
    font-size: 13px;
    color: var(--fa-muted);
    margin-bottom: 20px;
    border-bottom: 1px solid var(--fa-border);
    padding-bottom: 14px;
}

.fa-article-body h1 {
    font-size: 32px;
    margin-bottom: 24px;
}

.fa-article-body h2 {
    font-size: 22px;
    margin: 32px 0 16px;
    color: var(--fa-navy);
    border-left: 4px solid var(--fa-amber);
    padding-left: 12px;
}

.fa-article-body p {
    margin-bottom: 18px;
    color: #334155;
    line-height: 1.8;
}

.fa-article-body ul, .fa-article-body ol {
    margin: 18px 0 22px 24px;
    color: #334155;
}

.fa-article-body li {
    margin-bottom: 10px;
}

.fa-callout {
    background: #fefce8;
    border-left: 4px solid var(--fa-amber);
    padding: 20px 24px;
    border-radius: 0 8px 8px 0;
    margin: 28px 0;
    color: #854d0e;
    font-size: 15px;
}

/* Sidebar */
.fa-sidebar {
    display: flex;
    flex-direction: column;
    gap: 28px;
}

.fa-widget {
    background-color: #ffffff;
    border-radius: var(--fa-radius);
    padding: 24px;
    border: 1px solid var(--fa-border);
}

.fa-widget h3 {
    font-size: 18px;
    margin-bottom: 16px;
    color: var(--fa-navy);
    border-bottom: 2px solid var(--fa-border);
    padding-bottom: 8px;
}

.fa-data-list {
    list-style: none;
}

.fa-data-list li {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px dashed var(--fa-border);
    font-size: 14px;
}

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

.fa-data-list span {
    color: var(--fa-muted);
}

.fa-data-list strong {
    color: var(--fa-navy-dark);
}

.fa-sidebar-links {
    list-style: none;
}

.fa-sidebar-links li {
    padding: 8px 0;
    border-bottom: 1px solid #f8fafc;
}

.fa-sidebar-links a {
    color: var(--fa-navy);
    font-size: 14px;
    font-weight: 500;
}

.fa-sidebar-links a:hover {
    color: var(--fa-amber);
}

/* Footer */
.fa-footer {
    background-color: #051b2c;
    color: #cbd5e1;
    padding: 55px 0 25px;
    margin-top: 60px;
    border-top: 4px solid var(--fa-amber);
}

.fa-footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
    gap: 36px;
    margin-bottom: 40px;
}

.fa-footer h4 {
    color: #ffffff;
    font-size: 17px;
    margin-bottom: 16px;
}

.fa-footer p {
    font-size: 14px;
    color: #94a3b8;
    line-height: 1.6;
    margin-bottom: 14px;
}

.fa-footer-links {
    list-style: none;
}

.fa-footer-links li {
    margin-bottom: 10px;
}

.fa-footer-links a {
    color: #94a3b8;
    font-size: 14px;
}

.fa-footer-links a:hover {
    color: #fef3c7;
}

.fa-footer-entity {
    background-color: #0b2a42;
    border: 1px solid #164e63;
    border-radius: 8px;
    padding: 16px;
    font-size: 13px;
    color: #cbd5e1;
}

.fa-footer-entity strong {
    color: #fef3c7;
    display: block;
    margin-bottom: 6px;
}

.fa-footer-bottom {
    border-top: 1px solid #0f3d5e;
    padding-top: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    color: #94a3b8;
    flex-wrap: wrap;
    gap: 12px;
}

@media (max-width: 992px) {
    .fa-hero-grid, .fa-article-grid {
        grid-template-columns: 1fr;
    }
    .fa-grid-3, .fa-footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    .fa-grid-3, .fa-footer-grid {
        grid-template-columns: 1fr;
    }
    .fa-nav-menu {
        display: none;
    }
}