/* ================================
   Design Tokens & Resets
   ================================ */
:root {
    /* Colors */
    --clr-bg: #f5f7fa;
    --clr-foreground: #ffffff;
    --clr-primary: #3b82f6;
    --clr-secondary: #2563eb;
    --clr-accent: #6366f1;
    --clr-text: #1f2937;
    --clr-muted: #6b7280;

    /* Typography */
    --fs-xs: 0.75rem;
    --fs-sm: 0.875rem;
    --fs-base: 1rem;
    --fs-lg: 1.125rem;
    --fs-xl: 1.5rem;
    --fs-2xl: 2rem;
    --fs-3xl: 2.5rem;

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 2rem;
    --space-lg: 4rem;

    /* Effects */
    --radius: 0.75rem;
    --shadow-light: 0 4px 12px rgba(0, 0, 0, 0.05);
    --shadow-medium: 0 8px 24px rgba(0, 0, 0, 0.1);
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    background: var(--clr-bg);
    color: var(--clr-text);
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
}

/* ================================
     Global Utility Classes
     ================================ */
.section-title {
    font-size: var(--fs-2xl);
    margin-bottom: var(--space-md);
    font-weight: 600;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 4rem;
    height: 0.25rem;
    background: var(--clr-primary);
    border-radius: var(--radius);
    margin-top: var(--space-sm);
}

.btn {
    border-radius: var(--radius);
    font-weight: 500;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-light);
}

/* ================================
     Glassmorphism Navbar
     ================================ */
.glass-nav {
    background: rgb(0 78 255 / 33%);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: var(--shadow-medium);
    padding: var(--space-sm) 0;
}

.glass-nav .navbar-brand {
    letter-spacing: 1px;
}

.navbar-nav .nav-link {
    color: var(--clr-foreground);
    font-weight: 500;
    margin-left: var(--space-md);
}

.navbar-nav .nav-link:hover {
    color: var(--clr-secondary);
}

/* ================================
     Hero Section
     ================================ */
.hero-section {
    height: 90vh;
    background-size: cover;
    background-position: center;
    position: relative;
    display: flex;
    align-items: center;
}

.hero-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(180deg, rgb(0 78 255 / 33%), rgb(0 78 255 / 43%));
}

.hero-section .container {
    position: relative;
    z-index: 1;
}

.hero-section h1 {
    font-size: var(--fs-3xl);
    font-weight: 700;
}

.hero-section p {
    font-size: var(--fs-lg);
    margin-bottom: var(--space-md);
}

/* ================================
     Section Styles & Separators
     ================================ */
section {
    padding: var(--space-lg) 0;
    position: relative;
}

section:nth-of-type(even) {
    background: var(--clr-foreground);
}

section:nth-of-type(odd) {
    background: var(--clr-bg);
}

/* Decorative bottom wave */
section::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 4rem;
    background: inherit;
    clip-path: polygon(0 100%, 100% 0, 100% 100%);
    z-index: 1;
}

/* ================================
     Articles & Technique Items
     ================================ */
.technique-item {
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(8px);
    border-radius: var(--radius);
    box-shadow: var(--shadow-light);
    padding: var(--space-md);
    transition: transform 0.3s, box-shadow 0.3s;
}

.technique-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-medium);
}

.technique-item h3 {
    margin-bottom: var(--space-sm);
    font-size: var(--fs-xl);
    color: var(--clr-secondary);
}

.technique-item p,
.technique-item ul,
.technique-item ol {
    margin-bottom: var(--space-sm);
}

/* ================================
     Application Cards
     ================================ */
.app-card {
    background: var(--clr-foreground);
    border-radius: var(--radius);
    box-shadow: var(--shadow-light);
    transition: transform 0.3s;
}

.app-card:hover {
    transform: translateY(-3px);
}

.app-card h3 {
    color: var(--clr-primary);
    margin-bottom: var(--space-sm);
}

/* ================================
     Facts & Methods
     ================================ */
.fact-item {
    background: var(--clr-foreground);
    border-left: 4px solid var(--clr-primary);
    padding: var(--space-md);
    border-radius: var(--radius);
    box-shadow: var(--shadow-light);
    transition: background 0.3s;
}

.fact-item:hover {
    background: rgba(59, 130, 246, 0.05);
}

.fact-item h4 {
    margin-bottom: var(--space-sm);
    color: var(--clr-secondary);
}

/* ================================
     Checklist & Lists
     ================================ */
.list-check {
    list-style: none;
    padding-left: 0;
}

.list-check li {
    position: relative;
    padding-left: var(--space-lg);
    margin-bottom: var(--space-sm);
}

.list-check li::before {
    content: '✔';
    position: absolute;
    left: 0;
    top: 0;
    color: var(--clr-primary);
}

/* ================================
     Developments Timeline
     ================================ */
.development-list {
    list-style: none;
    position: relative;
    padding-left: var(--space-md);
}

.development-list::before {
    content: '';
    position: absolute;
    left: 1rem;
    top: 0.5rem;
    bottom: 0;
    width: 2px;
    background: var(--clr-accent);
}

.development-list li {
    position: relative;
    margin-bottom: var(--space-md);
    padding-left: var(--space-md);
}

.development-list li::before {
    content: '';
    position: absolute;
    left: -0.45rem;
    top: 0.25rem;
    width: 0.75rem;
    height: 0.75rem;
    background: var(--clr-primary);
    border-radius: 50%;
}

/* ================================
     Footer
     ================================ */
footer {
    background-color: #95b5fc;
    color: var(--clr-foreground);
}

footer h5 {
    font-size: var(--fs-lg);
    margin-bottom: var(--space-sm);
}

footer ul {
    padding-left: 0;
    list-style: none;
    margin: 0;
}

footer ul li {
    margin-bottom: 0.5rem;
}

footer a {
    color: black;
    text-decoration: none;
    transition: color 0.3s ease;
}

footer a:hover {
    color: #f5f7fa;
}

@media (max-width: 767.98px) {
    footer .row>div {
        text-align: center !important;
        align-items: center !important;
    }
}


/* ================================
     Smooth Reveal Animations
     ================================ */
@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

[data-reveal] {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeUp 0.6s ease forwards;
    animation-delay: var(--delay, 0s);
}