:root {
    --bg-color: #f4f4f4;
    --text-color: #0d0d0d;
    --text-muted: #555555;
    --line-color: rgba(0, 0, 0, 0.15);
    --font-main: 'Inter', Helvetica, sans-serif;
    --nav-bg: rgba(244, 244, 244, 0.82);
    --nav-text: #0d0d0d;
}

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

body {
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

#case-study-content {
    padding-top: 96px;
}

/* DESIGN LANGUAGE: STRUCTURAL LINES */
.section-line-bottom {
    border-bottom: 1px solid var(--line-color);
}

.section-line-top {
    border-top: 1px solid var(--line-color);
}

.border-right {
    border-right: 1px solid var(--line-color);
}

.grid-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
}

.grid-3-cols {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
}

.experience-gap-grid {
    display: grid;
    grid-template-columns: 1fr 2fr 2fr;
    gap: 3rem;
}

.impact-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
}

.case-flow-container {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    align-items: center;
}

.flow-arrow {
    color: var(--text-muted);
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Nav */
.nav {
    position: absolute;
    top: 24px;
    left: 50%;
    transform: translateX(-50%);
    width: 96%;
    max-width: 1600px;
    z-index: 50;
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 8px 32px;
    border-radius: 100px;
    background: rgba(255, 255, 255, 0.4);
    border: 1px solid rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(16px);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 48px;
    list-style: none;
    width: 100%;
}

.nav-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 8px 16px;
    border-radius: 100px;
    font-size: 1rem;
    color: var(--text-color);
    opacity: 0.8;
    text-decoration: none;
    transition: all 0.3s ease;
}

.nav-link:hover {
    background: rgba(0, 0, 0, 0.05);
    opacity: 1;
}

.nav-cta {
    background: var(--text-color);
    color: var(--bg-color);
    border: 1px solid transparent;
    margin-left: auto;
    font-weight: 500;
    opacity: 1;
}

.nav-cta:hover {
    background: #000000;
    color: #ffffff;
    transform: scale(1.02);
}

.dropdown { position: relative; }
.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 8px;
    background: var(--bg-color);
    border: 1px solid var(--line-color);
    padding: 8px 0;
    border-radius: 12px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.1);
    opacity: 0;
    visibility: hidden;
    min-width: 180px;
    list-style: none;
    margin-top: 16px;
    transition: all 0.3s ease;
}
.dropdown-menu::before {
    content: '';
    position: absolute;
    top: -24px;
    left: 0;
    right: 0;
    height: 24px;
}
.dropdown-menu li { padding: 8px 24px; }
.dropdown-menu li a {
    color: #555555;
    font-size: 1rem;
    text-decoration: none;
}
.dropdown-menu li a:hover {
    color: #0d0d0d;
}
.dropdown:hover .dropdown-menu { opacity: 1; visibility: visible; }

/* Typography Constraints */
h1, h2, h3, h4, h5, h6 {
    font-weight: 400; /* Prioritize less rigid weights to provide an elegant aesthetic and text focus */
    letter-spacing: -0.02em;
}

.mega-text {
    font-size: clamp(3rem, 6vw, 6.5rem);
    font-weight: 500;
    letter-spacing: -0.04em;
    line-height: 0.95;
    text-transform: uppercase;
}

.display-text {
    font-size: clamp(2rem, 3.5vw, 4rem);
    font-weight: 400;
    letter-spacing: -0.03em;
    line-height: 1.1;
}

.body-large {
    font-size: clamp(1rem, 1.2vw, 1.1rem);
    line-height: 1.5;
    color: rgba(0, 0, 0, 0.9);
    font-weight: 400;
}

.body-standard {
    font-size: 1rem;
    line-height: 1.6;
    color: rgba(0, 0, 0, 0.8);
}

.label-text {
    font-size: 0.85rem;
    margin-bottom: 3rem; /* Increase whitespace below label */
    display: block;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Massive Whitespaces Toned Down */
.px-main { padding-left: 4rem; padding-right: 4rem; }
.py-main { padding-top: 6rem; padding-bottom: 6rem; } /* Reduced from 8rem */
.py-sm { padding-top: 2.5rem; padding-bottom: 2.5rem; }
.px-sm { padding-left: 2rem; padding-right: 2rem; }

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

.flex-col-center {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
}

.image-wrapper {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding: 3rem; /* Push images inwards, maintaining focus on whitespace context */
}

.responsive-img {
    max-width: 100%;
    height: auto;
    display: block;
    object-fit: contain;
}

.max-w-lg { max-width: 600px; }
.mx-auto { margin-left: auto; margin-right: auto; }
.mb-main { margin-bottom: 3rem; }
.mb-sm { margin-bottom: 1rem; }
.text-center { text-align: center; }

/* Vertical Stepper Refined */
.stepper-container {
    position: relative;
    padding-left: 4rem; /* More breathing room */
    display: flex;
    flex-direction: column;
    gap: 4rem;
    margin-top: 2rem;
    margin-bottom: 2rem;
}

.stepper-container::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 1px;
    background-color: var(--line-color);
}

.step-item {
    position: relative;
    width: 100%;
}

.step-node {
    position: absolute;
    left: calc(-4rem - 4px);
    top: 2.5rem; 
    width: 8px;
    height: 8px;
    background-color: var(--bg-color);
    border: 1px solid var(--text-color); /* Emphasized node */
}

.step-card {
    border: none; /* Removing border to follow clean hierarchy */
    padding: 0;
    background-color: transparent;
}

.step-card h3 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

/* Comparison Grid */
.comparison-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.corp-col {
    border-right: 1px solid var(--line-color);
    padding-right: 2rem;
}

.step-tags {
    margin-top: 1rem;
    font-size: 0.7rem;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

/* Spheres (Problem & Solution) */
.spheres-container {
    position: relative; 
    height: 580px; 
    width: 100%; 
    max-width: 600px; 
    margin-top: 2rem;
}
.sphere-problem {
    width: 320px; 
    height: 320px; 
    background-color: #060b19; 
    border-radius: 50%; 
    color: #fff; 
    padding: 3.5rem; 
    display: flex; 
    flex-direction: column; 
    justify-content: center; 
    position: absolute; 
    top: 0; 
    left: 0; 
    z-index: 2; 
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
}
.sphere-solution {
    width: 360px; 
    height: 360px; 
    border-radius: 50%; 
    padding: 4rem; 
    display: flex; 
    flex-direction: column; 
    justify-content: center; 
    position: absolute; 
    top: 200px; 
    left: 220px; 
    z-index: 3; 
    background: linear-gradient(135deg, rgba(255,255,255,0.95) 0%, rgba(240,240,240,0.6) 100%); 
    backdrop-filter: blur(24px); 
    -webkit-backdrop-filter: blur(24px); 
    border: 1px solid rgba(255,255,255,0.8); 
    box-shadow: 0 30px 60px rgba(0,0,0,0.08);
}

/* Mobile Menu Toggle button */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    padding: 8px;
}

@media (max-width: 768px) {
    .grid-container, .grid-3-cols, .experience-gap-grid, .impact-grid {
        grid-template-columns: 1fr;
    }
    
    .case-flow-container {
        flex-direction: column;
        align-items: center;
    }
    
    .flow-arrow {
        transform: rotate(90deg);
        margin: 0.5rem 0;
    }
    
    .border-right {
        border-right: none;
        border-bottom: 1px solid var(--line-color);
    }
    .px-main { padding-left: 1.5rem; padding-right: 1.5rem; }
    .py-main { padding-top: 4rem; padding-bottom: 4rem; }
    .image-wrapper { padding: 1.5rem; }

    /* Comparison Grid Mobile */
    .comparison-grid {
        grid-template-columns: 1fr;
    }
    .corp-col {
        border-right: none;
        border-bottom: 1px solid var(--line-color);
        padding-right: 0;
        padding-bottom: 2rem;
    }

    /* Mobile Menu */
    .mobile-menu-toggle {
        display: block;
        margin-right: auto;
    }
    .nav-inner {
        justify-content: flex-end;
    }
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: rgba(255, 255, 255, 0.95);
        flex-direction: column;
        padding: 24px;
        gap: 24px;
        border-radius: 12px;
        box-shadow: 0 8px 32px rgba(0,0,0,0.1);
        margin-top: 16px;
    }
    .nav-links.is-open {
        display: flex;
    }
    .nav-cta {
        margin-left: 0;
        width: 100%;
    }

    /* Spheres Container Mobile */
    .spheres-container {
        height: auto;
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 2rem;
        margin-top: 0;
    }
    .sphere-problem, .sphere-solution {
        position: relative;
        top: 0;
        left: 0;
        width: 100%;
        max-width: 320px;
        height: auto;
        aspect-ratio: 1 / 1;
        padding: 2.5rem;
    }
    .sphere-solution {
        margin-top: -3rem; /* keep them overlapping slightly on mobile */
    }

    /* Behavioral Insight Mobile */
    .insight-card {
        padding: 2rem !important;
        gap: 2rem !important;
    }
    .insight-text {
        flex: 1 1 100% !important;
        min-width: 0;
    }
}