@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@300;400;500;600;700&family=Inter:wght@300;400;500;600&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRAD@20..48,100..700,0..1,-50..200');

:root {
    /* Color Palette */
    --clr-surface: #05132a;
    --clr-surface-container-lowest: #010e24;
    --clr-surface-container-low: #0d1c32;
    --clr-surface-container: #122037;
    --clr-surface-container-high: #1d2a42;
    --clr-surface-container-highest: #28354d;
    
    --clr-primary: #b2c5ff;
    --clr-primary-container: #2962d7;
    --clr-on-primary-container: #e4e9ff;
    
    --clr-secondary: #ffb59c;
    
    --clr-on-surface: #d7e3ff;
    --clr-on-surface-variant: #c3c6d6;
    
    --clr-outline: #8d909f;
    --clr-outline-variant: #434654;

    /* Typography */
    --font-display: 'Space Grotesk', sans-serif;
    --font-functional: 'Inter', sans-serif;

    /* Metrics & Spacing */
    --radius-sm: 0.125rem;
    --radius-md: 0.375rem;
    --radius-full: 9999px;
    
    --transition-fast: 0.2s ease-out;
    --transition-slow: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

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

body {
    background-color: var(--clr-surface);
    color: var(--clr-on-surface);
    font-family: var(--font-functional);
    overflow: hidden; /* Fixed Viewport Philosophy */
}

/* Material Symbols Override */
.material-symbols-outlined {
    font-size: 24px;
    font-variation-settings: 'FILL' 0, 'wght' 400, 'GRAD' 0, 'opsz' 24;
}

/* Typography Classes */
.display-lg {
    font-family: var(--font-display);
    font-size: clamp(3rem, 6vw, 5rem);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.headline-md {
    font-family: var(--font-display);
    font-size: clamp(2rem, 3vw, 2.5rem);
    font-weight: 700;
}

.title-sm {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
}

.body-lg {
    font-family: var(--font-functional);
    font-size: 1.125rem;
    line-height: 1.6;
    color: var(--clr-on-surface-variant);
}

.label-md {
    font-family: var(--font-functional);
    font-size: 0.625rem; /* 10px */
    text-transform: uppercase;
    letter-spacing: 0.3em;
    font-weight: 600;
    color: var(--clr-outline);
}

.editorial-gap {
    letter-spacing: 0.05em;
}

/* Layout & Canvas */
.canvas-container {
    height: 100vh;
    width: 100vw;
    overflow-y: auto;
    scroll-snap-type: y mandatory;
    scrollbar-width: none; /* Firefox */
}

.canvas-container::-webkit-scrollbar {
    display: none; /* Chrome/Safari */
}

.snap-section {
    min-height: 100vh;
    scroll-snap-align: start;
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: relative;
    padding: 2rem 6vw;
}

/* Background & Atmosphere */
.atmosphere-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: radial-gradient(circle at 50% 50%, var(--clr-surface-container-low) 0%, var(--clr-surface) 100%);
}

.data-flow-svg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0.15;
    pointer-events: none;
    transition: transform 0.1s ease-out; /* For JS parallax */
}

/* Components */
/* Top Nav (Glassmorphism) */
.nav-bar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 50;
    background: rgba(5, 19, 42, 0.6);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05); /* Ghost border */
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

.nav-brand {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.05em;
    color: var(--clr-primary);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    font-family: var(--font-display);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    font-size: 0.625rem;
    font-weight: 700;
    color: rgba(178, 197, 255, 0.7);
    text-decoration: none;
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
    color: var(--clr-primary);
    background: rgba(255, 255, 255, 0.05);
}

.nav-link.active {
    border-bottom: 2px solid var(--clr-secondary);
    border-radius: 0;
}

/* Cards */
.glass-card {
    background: rgba(18, 32, 55, 0.6);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(67, 70, 84, 0.15); /* Ghost Border */
    border-radius: var(--radius-md);
    padding: 2rem;
    position: relative;
    overflow: hidden;
    transition: var(--transition-slow);
}

.glass-card[data-active="true"] {
    background: var(--clr-surface-container-high);
    border-color: rgba(178, 197, 255, 0.15);
}

.glass-card .active-node {
    position: absolute;
    top: 1rem;
    right: 1rem;
    width: 4px;
    height: 4px;
    background-color: var(--clr-secondary);
}

.glass-card:hover {
    background: var(--clr-surface-container-highest);
    transform: translateY(-2px);
    box-shadow: 0 10px 40px rgba(178, 197, 255, 0.06);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-family: var(--font-display);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    padding: 1rem 2rem;
    border: none;
    transition: var(--transition-fast);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--clr-primary) 0%, var(--clr-primary-container) 100%);
    color: var(--clr-on-primary-container);
    border-radius: var(--radius-sm);
}

.btn-primary:hover {
    filter: brightness(1.1);
    box-shadow: 0 0 20px rgba(41, 98, 215, 0.4);
}

.btn-secondary {
    background: transparent;
    color: var(--clr-primary);
    border: 1px solid rgba(67, 70, 84, 0.2); /* outline-variant 20% */
    border-radius: var(--radius-sm);
}

.btn-secondary:hover {
    background: var(--clr-surface-container-highest); /* shift to surface bright approximation */
}

/* Input Fields */
.input-group {
    position: relative;
    margin-bottom: 2rem;
}

.input-field {
    width: 100%;
    background: transparent;
    border: none;
    border-bottom: 1px solid rgba(141, 144, 159, 0.3); /* outline 30% */
    color: var(--clr-on-surface);
    font-family: var(--font-functional);
    font-size: 1rem;
    padding: 0.75rem 0;
    transition: var(--transition-fast);
}

.input-field:focus {
    outline: none;
    border-bottom-color: var(--clr-primary);
    background: rgba(178, 197, 255, 0.05); /* surface_tint glow */
}

.input-label {
    display: block;
    margin-bottom: 0.5rem;
    transition: var(--transition-fast);
}

.input-field:focus + .input-label,
.input-group:focus-within .input-label {
    color: var(--clr-primary);
}

/* Grid & Utilities */
.grid-3-col {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.text-primary-gradient {
    color: transparent;
    background-clip: text;
    -webkit-background-clip: text;
    background-image: linear-gradient(to right, var(--clr-primary), var(--clr-primary-container));
}

.text-secondary {
    color: var(--clr-secondary);
}

.hero-image-container {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 33%;
    height: 66%;
    overflow: hidden;
    border-top-left-radius: 1.5rem;
    border-bottom-left-radius: 1.5rem;
    border-left: 1px solid rgba(67, 70, 84, 0.2);
    border-top: 1px solid rgba(67, 70, 84, 0.2);
    border-bottom: 1px solid rgba(67, 70, 84, 0.2);
    background-color: var(--clr-surface-container-low);
    display: none;
}

@media (min-width: 1024px) {
    .hero-image-container {
        display: block;
    }
}

.hero-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    mix-blend-mode: screen;
    opacity: 0.6;
}

/* Flex utils */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.items-center { align-items: center; }
.gap-2 { gap: 0.5rem; }
.gap-4 { gap: 1rem; }
.gap-8 { gap: 2rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-4 { margin-bottom: 1rem; }
.mb-8 { margin-bottom: 2rem; }
.max-w-m { max-width: 600px; }
.max-w-l { max-width: 900px; }

/* Desktop overrides */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .display-lg { font-size: 2.5rem; }
    .snap-section { padding: 4rem 2rem; }
}

/* Footer */
.footer {
    border-top: 1px solid rgba(255,255,255,0.05); /* Ghost border */
    background: var(--clr-surface-container-low);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 2rem 4rem;
    scroll-snap-align: end;
}
.footer-links a {
    color: var(--clr-outline);
    text-decoration: none;
    margin-left: 1.5rem;
    font-size: 0.875rem;
    transition: var(--transition-fast);
}
.footer-links a:hover {
    color: var(--clr-primary);
}