/* BASE STYLES & VARIABLES */
:root {
    --deep-rail-blue: #18324A;
    --steel-blue: #3F6578;
    --signal-red: #C9574D;
    --signal-amber: #D6A84F;
    --rail-green: #5E8B72;
    --industrial-teal: #3F8582;
    --concrete: #D9D6CF;
    --mist: #EEF1EF;
    --paper: #F7F4EC;
    --white: #FFFFFF;
    --dark-text: #26343B;
    
    --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --font-mono: 'SFMono-Regular', Consolas, "Liberation Mono", Menlo, monospace;
    
    --header-height: 80px;
}

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

body {
    font-family: var(--font-main);
    color: var(--dark-text);
    background-color: var(--paper);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--deep-rail-blue);
}

p {
    margin-bottom: 1.5rem;
}

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

a:hover {
    color: var(--signal-red);
}

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

ul, ol {
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
}

/* TYPOGRAPHY UTILS */
.mono {
    font-family: var(--font-mono);
    font-size: 0.9em;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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

/* LAYOUT */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 60px 0;
}

.section-dark {
    background-color: var(--deep-rail-blue);
    color: var(--white);
}

.section-dark h1, .section-dark h2, .section-dark h3 {
    color: var(--white);
}

.section-alt {
    background-color: var(--mist);
}

/* HEADER & NAVIGATION */
header {
    background-color: var(--deep-rail-blue);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 2px solid var(--steel-blue);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    min-height: var(--header-height);
    flex-wrap: wrap;
    padding: 10px 20px;
}

.brand-link {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    color: var(--white);
    font-weight: bold;
    letter-spacing: 0.05em;
    display: flex;
    align-items: center;
    gap: 10px;
}

.brand-link:hover {
    color: var(--signal-amber);
}

.nav-desktop {
    display: flex;
    gap: 15px;
    align-items: center;
    flex-wrap: wrap;
}

.nav-desktop a {
    color: var(--mist);
    font-size: 0.9rem;
    padding: 5px 10px;
}

.nav-desktop a:hover {
    color: var(--white);
    background-color: var(--steel-blue);
    border-radius: 3px;
}

.cta-button {
    background-color: var(--signal-amber);
    color: var(--deep-rail-blue) !important;
    font-weight: bold;
    padding: 8px 16px !important;
    border-radius: 2px;
}

.cta-button:hover {
    background-color: var(--white);
}

/* BUTTONS */
.btn {
    display: inline-block;
    padding: 12px 24px;
    background-color: var(--steel-blue);
    color: var(--white);
    font-family: var(--font-mono);
    font-weight: bold;
    border: none;
    cursor: pointer;
    text-align: center;
    transition: background 0.2s;
    border-radius: 2px;
}

.btn:hover {
    background-color: var(--deep-rail-blue);
    color: var(--white);
}

.btn-primary {
    background-color: var(--industrial-teal);
}

.btn-primary:hover {
    background-color: var(--deep-rail-blue);
}

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

.btn-outline:hover {
    background-color: var(--white);
    color: var(--deep-rail-blue);
}

/* HERO SECTION */
.hero {
    background-color: var(--deep-rail-blue);
    color: var(--white);
    padding: 100px 0;
    position: relative;
    overflow: hidden;
    border-bottom: 8px solid var(--signal-red);
}

.hero::before {
    content: '';
    position: absolute;
    top: 0; right: 0; bottom: 0; left: 0;
    background-image: 
        linear-gradient(var(--steel-blue) 1px, transparent 1px),
        linear-gradient(90deg, var(--steel-blue) 1px, transparent 1px);
    background-size: 50px 50px;
    opacity: 0.2;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.hero h1 {
    color: var(--white);
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.hero p {
    font-size: 1.2rem;
    color: var(--mist);
    margin-bottom: 2rem;
}

.hero-actions {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

/* SCHEMATIC UI ELEMENTS (RAIL / SIGNAL / STRUCTURE) */
.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 2rem;
}

.tech-panel {
    background-color: var(--white);
    border: 1px solid var(--concrete);
    border-top: 4px solid var(--steel-blue);
    padding: 24px;
    position: relative;
}

.tech-panel.red-top { border-top-color: var(--signal-red); }
.tech-panel.amber-top { border-top-color: var(--signal-amber); }
.tech-panel.green-top { border-top-color: var(--rail-green); }

.panel-label {
    position: absolute;
    top: -12px;
    right: 20px;
    background-color: var(--mist);
    padding: 2px 8px;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--deep-rail-blue);
    border: 1px solid var(--concrete);
}

/* INTERACTIVE DIAGRAMS */
.diagram-container {
    background-color: var(--mist);
    border: 2px solid var(--concrete);
    display: flex;
    flex-direction: column;
    margin-bottom: 2rem;
}

@media(min-width: 768px) {
    .diagram-container {
        flex-direction: row;
    }
}

.diagram-nav {
    background-color: var(--deep-rail-blue);
    flex: 0 0 250px;
    display: flex;
    flex-direction: column;
}

.diagram-nav button {
    background: none;
    border: none;
    border-bottom: 1px solid var(--steel-blue);
    color: var(--mist);
    padding: 15px 20px;
    text-align: left;
    font-family: var(--font-mono);
    cursor: pointer;
    transition: all 0.2s;
}

.diagram-nav button:hover {
    background-color: var(--steel-blue);
    color: var(--white);
}

.diagram-nav button.active {
    background-color: var(--signal-red);
    color: var(--white);
    font-weight: bold;
    border-left: 4px solid var(--white);
}

.diagram-content {
    padding: 30px;
    flex-grow: 1;
    background-color: var(--white);
}

.diagram-pane {
    display: none;
}

.diagram-pane.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* SYSTEM CONNECTION MAP */
.flow-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    margin: 2rem 0;
}

.flow-node {
    background-color: var(--steel-blue);
    color: var(--white);
    padding: 15px 30px;
    font-family: var(--font-mono);
    font-weight: bold;
    border-radius: 4px;
    cursor: pointer;
    width: 250px;
    text-align: center;
    border: 2px solid transparent;
    transition: all 0.2s;
}

.flow-node:hover, .flow-node.active {
    background-color: var(--deep-rail-blue);
    border-color: var(--signal-amber);
}

.flow-arrow {
    color: var(--signal-red);
    font-size: 1.5rem;
}

.flow-details {
    background-color: var(--mist);
    padding: 20px;
    border-left: 4px solid var(--signal-amber);
    width: 100%;
    max-width: 600px;
    display: none;
}

.flow-details.active {
    display: block;
}

/* INFRASTRUCTURE CHECKLIST */
.checklist-container {
    background-color: var(--white);
    border: 1px solid var(--concrete);
    padding: 2rem;
}

.check-item {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--mist);
}

.check-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.check-item input[type="checkbox"] {
    width: 20px;
    height: 20px;
    margin-top: 4px;
    accent-color: var(--industrial-teal);
}

.check-item label {
    font-weight: 600;
    display: block;
    cursor: pointer;
}

.check-item p {
    margin-bottom: 0;
    font-size: 0.9rem;
    color: #555;
}

/* GLOSSARY */
.glossary-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

@media(min-width: 768px) {
    .glossary-list {
        grid-template-columns: 1fr 1fr;
    }
}

.glossary-term {
    background: var(--white);
    padding: 20px;
    border-left: 4px solid var(--steel-blue);
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.glossary-term dt {
    font-family: var(--font-mono);
    font-weight: bold;
    color: var(--deep-rail-blue);
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.glossary-term dd {
    margin-left: 0;
    color: var(--dark-text);
}

/* FORMS */
.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    font-family: var(--font-mono);
    font-size: 0.9rem;
}

input[type="text"],
input[type="email"],
select,
textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--concrete);
    background-color: var(--paper);
    font-family: var(--font-main);
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--steel-blue);
    background-color: var(--white);
}

.form-error {
    color: var(--signal-red);
    font-size: 0.8rem;
    margin-top: 5px;
    display: none;
}

/* FOOTER */
footer {
    background-color: var(--deep-rail-blue);
    color: var(--white);
    padding: 60px 0 20px;
    border-top: 4px solid var(--industrial-teal);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    color: var(--mist);
    font-family: var(--font-mono);
    margin-bottom: 20px;
}

.footer-col ul {
    list-style: none;
    padding: 0;
}

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

.footer-col a {
    color: var(--white);
}

.footer-col a:hover {
    color: var(--signal-amber);
}

.footer-bottom {
    border-top: 1px solid var(--steel-blue);
    padding-top: 20px;
    text-align: center;
    font-size: 0.85rem;
    color: var(--mist);
}

.editorial-note {
    margin-top: 15px;
    font-style: italic;
    color: var(--concrete);
}

/* COOKIE BANNER */
#cookie-banner {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: var(--paper);
    border-top: 4px solid var(--signal-amber);
    padding: 20px;
    box-shadow: 0 -4px 10px rgba(0,0,0,0.1);
    z-index: 9999;
    display: none;
}

#cookie-banner.visible {
    display: block;
}

.cookie-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

@media(min-width: 768px) {
    .cookie-content {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }
}

.cookie-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.cookie-actions button {
    padding: 8px 16px;
    border: none;
    cursor: pointer;
    font-family: var(--font-mono);
    font-weight: bold;
}

#btn-accept-cookies { background-color: var(--deep-rail-blue); color: var(--white); }
#btn-reject-cookies { background-color: var(--concrete); color: var(--dark-text); }
#btn-manage-cookies { background-color: transparent; border: 1px solid var(--steel-blue); color: var(--steel-blue); }

/* RESPONSIVE UTILS */
@media (max-width: 1200px) {
    .nav-desktop {
        gap: 10px;
    }
}

@media (max-width: 768px) {
    .nav-desktop {
        flex-direction: column;
        align-items: flex-start;
        width: 100%;
        margin-top: 15px;
        border-top: 1px solid var(--steel-blue);
        padding-top: 15px;
    }
    .header-inner {
        flex-direction: column;
        align-items: flex-start;
    }
    .hero h1 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    body {
        overflow-x: hidden;
    }
    .hero-actions {
        flex-direction: column;
        width: 100%;
    }
    .hero-actions .btn {
        width: 100%;
    }
    .tech-grid {
        grid-template-columns: 1fr;
    }
}

.image-wrapper {
    margin-bottom: 2rem;
    border: 4px solid var(--white);
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.image-wrapper img {
    width: 100%;
    height: auto;
    object-fit: cover;
}

/* History Timeline */
.timeline {
    border-left: 4px solid var(--steel-blue);
    padding-left: 20px;
    margin-left: 20px;
}
.timeline-item {
    position: relative;
    margin-bottom: 30px;
}
.timeline-item::before {
    content: '';
    position: absolute;
    left: -30px;
    top: 5px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--signal-amber);
    border: 2px solid var(--white);
}
.timeline-date {
    font-family: var(--font-mono);
    font-weight: bold;
    color: var(--industrial-teal);
    margin-bottom: 5px;
}