:root {
    --aura-dark-blue: #111827;
    --aura-dark-gray: #1F2937; /* For card backgrounds */
    --aura-neon-blue: #22d3ee;
    --aura-light-gray: #E5E7EB;
    --aura-medium-gray: #9CA3AF;
    --aura-white: #FFFFFF;
    --aura-gradient-start: rgba(30, 58, 138, 0.3);

    /* --- FINAL FONT PALETTE --- */
    --font-display: 'Orbitron', sans-serif;
    --font-heading: 'Exo 2', sans-serif;
    --font-body: 'Overpass', sans-serif;
}

/* --- Scroll Snap --- */
html {
    scroll-snap-type: y mandatory;
}

body, html {
    overflow-x: hidden; /* Prevent horizontal scrollbars */
}

header, section, footer {
    scroll-snap-align: start;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

/* --- Base & Typography --- */
body {
    font-family: var(--font-body);
    padding-top: 56px;
    background-color: var(--aura-dark-blue);
    color: var(--aura-light-gray);
    font-size: 1.1rem;
    line-height: 1.7;
}

p {
    font-family: var(--font-body);
}

h1, .h1, h2, .h2, h3, .h3, h5, .h5, .section-heading {
    font-family: var(--font-heading);
    color: var(--aura-white);
    font-weight: 700;
}

h3, .h3, h5, .h5 {
    color: var(--aura-neon-blue);
    font-weight: 700;
}

h1, .h1 { font-size: calc(1.475rem + 2.7vw); }
h2, .h2, .section-heading { font-size: calc(1.325rem + 0.9vw); }
h3, .h3 { font-size: calc(1.25rem + 0.6vw); }

.masthead h1 {
    font-family: var(--font-display);
    font-size: calc(1.6rem + 4.5vw);
    font-weight: 900;
    text-transform: uppercase;
}

.masthead h1 .text-subtitle-h1 {
    font-size: 0.5em; /* Approximately half the size of the parent h1 */
    font-weight: 700; /* Slightly less bold */
    display: block; /* Ensures it goes to a new line */
    margin-top: 0.2em; /* Small space above it */
    line-height: 1.2; /* Adjust line height for smaller text */
}

.lead {
    font-size: 1.3rem;
    font-weight: 300;
    color: var(--aura-light-gray);
}

.text-detail {
    font-size: 0.9rem;
    color: var(--aura-medium-gray);
    font-weight: 300; /* Lighter weight for detail text */
}

.text-muted {
    color: var(--aura-medium-gray) !important;
}

/* --- Layout & Spacing --- */
section {
    padding-top: 7rem;
    padding-bottom: 7rem;
}

hr.my-4 {
    border-color: var(--aura-neon-blue);
    border-width: 2px;
    opacity: 0.5;
    max-width: 100px;
    margin: 2rem auto;
}

/* --- Masthead --- */
.masthead {
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-image: 
        radial-gradient(ellipse at center, var(--aura-gradient-start) 0%, rgba(17, 24, 39, 0) 70%),
        linear-gradient(to bottom, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.8)), 
        url('https://source.unsplash.com/1600x900/?abstract,future,home');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    color: var(--aura-white);
}

.masthead .lead {
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

/* --- Bootstrap Overrides --- */
.bg-dark {
    background-color: var(--aura-dark-blue) !important;
}

/* --- Navigation --- */
.navbar {
    transition: background-color 0.3s ease-in-out;
}

.navbar-dark .navbar-brand {
    font-family: var(--font-display); /* Use display font for brand */
    color: var(--aura-white);
    font-weight: 700;
    font-size: 1.5rem;
}

.navbar-dark .navbar-brand:hover, .navbar-dark .navbar-brand:focus {
    color: var(--aura-neon-blue);
}

.navbar-dark .navbar-nav .nav-link {
    color: var(--aura-light-gray);
}

.navbar-dark .navbar-nav .nav-link:hover, .navbar-dark .navbar-nav .nav-link:focus {
    color: var(--aura-neon-blue);
}

.navbar-dark .navbar-nav .nav-link.active {
    color: var(--aura-neon-blue);
    font-weight: 500;
}

.navbar-toggler {
    border-color: rgba(255, 255, 255, 0.2);
}

.navbar-toggler-icon {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%2834, 211, 238, 0.8%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
}

/* --- Generic Interactive Card --- */
.interactive-card {
    background-color: var(--aura-dark-gray);
    padding: 2.5rem;
    border-radius: 0.5rem;
    border: 1px solid #1F2937;
    height: 100%;
    transition: all 0.3s ease-in-out;
}

.interactive-card:hover {
    transform: translateY(-5px);
    border-color: var(--aura-neon-blue);
    box-shadow: 0 0 25px rgba(34, 211, 238, 0.25);
}

.interactive-card h3 {
    margin-bottom: 1rem;
}

.interactive-card h5 {
    margin-bottom: 1rem;
    font-size: 1.6rem; /* Increased font size */
}

/* Horizontal variation for the problem section */
.interactive-card-horizontal {
    display: flex;
    align-items: flex-start;
    padding: 2rem; /* slightly less padding for horizontal */
}

.interactive-card-icon {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    margin-right: 2rem;
    color: var(--aura-neon-blue);
}

#tech-stack span {
    font-family: var(--font-body);
    display: inline-block;
    padding: 0.6rem 1.2rem;
    border: 1px solid var(--aura-dark-gray);
    background-color: var(--aura-dark-gray);
    border-radius: 0.25rem;
    margin: 0.5rem;
    font-weight: 500;
    color: var(--aura-light-gray);
    transition: all 0.2s ease-in-out;
}

#tech-stack span:hover {
    border-color: var(--aura-neon-blue);
    color: var(--aura-neon-blue);
    transform: translateY(-2px);
}

/* --- Footer --- */
footer {
    /* The background is now handled by the card inside */
}

footer .section-heading {
    margin-bottom: 2rem; /* More space below heading */
}

footer p {
    margin-bottom: 1.5rem; /* More space for paragraphs */
}

footer a {
    color: var(--aura-neon-blue);
    text-decoration: none;
    transition: color 0.2s;
    margin: 0 1.5rem; /* Increased horizontal spacing */
}

footer a:hover {
    color: var(--aura-white);
    text-decoration: underline;
}

/* --- Problem Card (Horizontal) --- */
.card-problem-horizontal {
    display: flex;
    align-items: flex-start;
    background-color: var(--aura-dark-gray);
    padding: 2rem;
    border-radius: 0.5rem;
    border: 1px solid #1f2937;
    transition: all 0.3s ease-in-out;
}
.card-problem-horizontal:hover {
    transform: translateY(-5px);
    border-color: var(--aura-neon-blue);
    box-shadow: 0 0 20px rgba(34, 211, 238, 0.2);
}
.card-problem-icon {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    margin-right: 2rem;
    color: var(--aura-neon-blue);
}
.card-problem-content h3 {
    margin-bottom: 0.5rem;
}

/* --- Timeline for Roadmap --- */
.timeline-container {
    display: flex;
    justify-content: space-between;
    position: relative;
    margin-top: 4rem;
}

.timeline-container::before {
    content: '';
    position: absolute;
    top: 5px; /* Vertically center with the marker */
    left: 0;
    right: 0;
    height: 3px;
    background-color: var(--aura-neon-blue);
    box-shadow: 0 0 10px var(--aura-neon-blue);
    border-radius: 2px;
}

.timeline-phase {
    flex: 1;
    padding: 0 2rem;
    position: relative;
    text-align: center;
}

.timeline-marker {
    position: absolute;
    top: -2px; /* Position on the line */
    left: 50%;
    transform: translateX(-50%);
    width: 15px;
    height: 15px;
    background-color: var(--aura-dark-blue);
    border: 3px solid var(--aura-neon-blue);
    border-radius: 50%;
    z-index: 1;
}

.timeline-content {
    margin-top: 30px; /* Space below the line */
}