/* --- 1. GLOBAL VARIABLES & RESET --- */
:root {
    --bg-body: #f8f9fa;       /* Off-white background for main page */
    --bg-dark: #0b1221;       /* Deep Navy for high-contrast sections */
    --text-main: #111111;     /* Nearly black for primary text */
    --text-muted: #555555;    /* Grey for secondary text */
    --text-light: #e0e0e0;    /* Light grey for text on dark backgrounds */
    
    --accent-blue: #0056b3;   /* Academic/Corporate Blue */
    --accent-cyan: #00e5ff;   /* Electric Cyan for tech highlights */
    
    --card-white: #ffffff;
    --header-height: 80px;

    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: var(--font-body);
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
    padding-top: var(--header-height); /* Prevent header from covering content */
}

a { text-decoration: none; color: inherit; transition: all 0.3s ease; }
ul { list-style: none; }

/* --- 2. TYPOGRAPHY --- */
h1, h2, h3, h4 { font-family: var(--font-heading); font-weight: 700; line-height: 1.2; }

h1 { font-size: 3.5rem; letter-spacing: -1.5px; color: var(--text-main); }
h2 { font-size: 2.5rem; margin-bottom: 1.5rem; color: var(--text-main); }
h3 { font-size: 1.5rem; margin-bottom: 1rem; }

.text-accent { color: var(--accent-blue); }
.text-cyan { color: var(--accent-cyan); }

/* --- 3. LAYOUT UTILITIES --- */
.container { 
    max-width: 1200px; 
    margin: 0 auto; 
    padding: 0 20px; 
}

.section { padding: 100px 0; }

.grid-2 { 
    display: grid; 
    grid-template-columns: 1fr 1fr; 
    gap: 60px; 
    align-items: center; 
}

.grid-3 { 
    display: grid; 
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); 
    gap: 30px; 
}

/* --- 4. HEADER & LOGO --- */
.site-header {
    position: fixed;
    top: 0; left: 0; width: 100%;
    height: var(--header-height);
    background: rgba(248, 249, 250, 0.9); /* Translucent off-white */
    backdrop-filter: blur(10px);          /* Glass effect */
    border-bottom: 1px solid rgba(0,0,0,0.05);
    z-index: 1000;
    display: flex; align-items: center;
}

.logo-group {
    display: flex; align-items: center; gap: 12px;
}

/* CSS Monogram Logo */
.logo-mark {
    width: 42px; height: 42px;
    background: var(--text-main);
    color: white;
    font-family: var(--font-heading);
    font-weight: 800; font-size: 1.2rem;
    display: flex; align-items: center; justify-content: center;
    border-radius: 8px;
    position: relative;
    overflow: hidden;
}
.logo-mark::after {
    content: ''; position: absolute; bottom: 0; right: 0;
    width: 14px; height: 14px;
    background: var(--accent-blue);
    border-top-left-radius: 100%;
}

.logo-text { 
    font-family: var(--font-heading); 
    font-size: 1.4rem; 
    font-weight: 800; 
    letter-spacing: -0.5px; 
}

/* Navigation */
.nav-menu { display: flex; gap: 30px; align-items: center; }
.nav-link { font-weight: 600; font-size: 0.95rem; color: var(--text-muted); }
.nav-link:hover { color: var(--accent-blue); }

/* --- 5. BUTTONS --- */
.btn { 
    display: inline-flex; align-items: center; gap: 10px;
    padding: 12px 28px; border-radius: 50px; 
    font-weight: 600; font-size: 0.95rem; 
    cursor: pointer;
}
.btn-primary { 
    background: var(--text-main); color: white; border: 2px solid var(--text-main); 
}
.btn-primary:hover { 
    background: var(--accent-blue); border-color: var(--accent-blue); 
    transform: translateY(-2px); 
}
.btn-outline { 
    background: transparent; color: var(--text-main); border: 2px solid var(--text-main); 
}
.btn-outline:hover { 
    background: var(--text-main); color: white; 
}

/* --- 6. HERO SECTION --- */
.hero {
    min-height: 85vh;
    display: flex; align-items: center;
    background: radial-gradient(circle at top right, rgba(0, 229, 255, 0.08), transparent 50%);
}

.hero-role { 
    font-size: 1.25rem; color: var(--text-muted); 
    margin: 20px 0 40px; font-weight: 400; max-width: 600px; 
}

.hero-img-wrap { 
    position: relative; z-index: 1; 
}
.hero-img-wrap::before {
    content: ''; position: absolute; top: 20px; right: -20px;
    width: 100%; height: 100%; 
    border: 3px solid var(--accent-blue); 
    border-radius: 12px; z-index: -1;
}
.hero-img { 
    width: 100%; max-width: 480px; 
    border-radius: 12px; 
    box-shadow: 0 25px 50px rgba(0,0,0,0.1); 
}

/* --- 7. CAPABILITIES SECTION (Dark Theme) --- */
#capabilities {
    background-color: var(--bg-dark);
    color: white;
}

#capabilities h2 { color: white; }
#capabilities p { color: var(--text-light); }

/* Value Cards (Left Col) */
.value-card {
    background: rgba(255,255,255,0.03);
    border: 1px solid rgba(255,255,255,0.1);
    padding: 30px; margin-bottom: 20px;
    border-radius: 12px;
    border-left: 4px solid var(--accent-blue);
}
.value-card h4 { color: white; font-size: 1.2rem; margin-bottom: 10px; }
.value-card p { font-size: 0.95rem; margin: 0; opacity: 0.9; }

/* Skill Tags (Right Col) */
.skill-group { margin-bottom: 35px; }
.skill-title { 
    color: var(--accent-cyan); 
    font-size: 0.9rem; text-transform: uppercase; letter-spacing: 1px; font-weight: 700;
    margin-bottom: 15px; display: block;
}
.skill-tags { display: flex; flex-wrap: wrap; gap: 10px; }
.tag {
    background: rgba(255,255,255,0.08);
    color: white;
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 0.9rem; font-weight: 500;
    border: 1px solid rgba(255,255,255,0.1);
    display: flex; align-items: center; gap: 8px;
}
.tag i { color: var(--accent-cyan); }

/* --- 8. RESEARCH CARDS --- */
.paper-card {
    background: var(--card-white);
    padding: 40px; border-radius: 12px;
    border: 1px solid #eeeeee;
    border-top: 5px solid var(--accent-blue);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.paper-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.08);
}
.paper-type { 
    font-size: 0.75rem; font-weight: 800; color: var(--accent-blue); 
    text-transform: uppercase; letter-spacing: 1px; 
}
.paper-title { font-size: 1.4rem; margin: 15px 0; color: var(--text-main); }
.paper-conf { 
    margin-top: 20px; padding-top: 20px; border-top: 1px solid #f0f0f0; 
    font-size: 0.9rem; color: var(--text-muted); display: flex; align-items: center; gap: 8px; 
}

/* --- 9. FOOTER --- */
footer {
    background: #050a10; color: white; padding: 60px 0; border-top: 1px solid #1a1a1a;
}
.footer-socials a {
    color: #888; font-size: 1.5rem; margin-right: 20px;
}
.footer-socials a:hover { color: var(--accent-cyan); }

/* --- 10. RESPONSIVE --- */
@media (max-width: 900px) {
    .grid-2 { grid-template-columns: 1fr; gap: 40px; }
    .hero { padding: 60px 0; text-align: center; }
    .hero-img-wrap { margin: 40px auto 0; }
    .site-header .container { justify-content: space-between; }
    .nav-menu { display: none; /* Collapsed for simplicity on small screens */ }
}