:root {
    /* Light Mode Variables */
    --bg-color: #f4f4f5;
    --text-color: #18181b;
    --text-secondary: #52525b;
    --card-bg: #ffffff;
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-btn: #71717a;
    --secondary-btn-hover: #52525b;
    --border-color: #e4e4e7;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --nav-bg: rgba(255, 255, 255, 0.8);
}

[data-theme="dark"] {
    /* Dark Mode Variables */
    --bg-color: #09090b;
    --text-color: #f4f4f5;
    --text-secondary: #a1a1aa;
    --card-bg: #18181b;
    --primary-color: #3b82f6;
    --primary-hover: #60a5fa;
    --secondary-btn: #52525b;
    --secondary-btn-hover: #71717a;
    --border-color: #27272a;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.18);
    --nav-bg: rgba(9, 9, 11, 0.8);
}

/* RESET & BASICS */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

/* NAVIGATION */
nav {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: var(--nav-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
}

.nav-content {
    width: 90%;
    max-width: 1100px;
    margin: auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 20px;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--primary-color);
}

/* THEME TOGGLE */
#theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 5px;
    transition: transform 0.3s, color 0.3s;
}

#theme-toggle:hover {
    color: var(--primary-color);
    transform: rotate(15deg);
}

/* HERO SECTION */
#hero {
    padding: 6rem 1rem;
    text-align: center;
    background-color: var(--bg-color);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.profile-container {
    margin-bottom: 2rem;
}

.profile-pic {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid var(--primary-color);
    box-shadow: var(--shadow);
}

#hero h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.subtitle {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 1.5rem;
    opacity: 1; /* Override old opacity */
}

.bio {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 2.5rem;
    line-height: 1.8;
}

.hero-actions {
    margin-bottom: 2.5rem;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.social-links a {
    color: var(--text-secondary);
    font-size: 1.5rem;
    transition: color 0.3s, transform 0.3s;
}

.social-links a:hover {
    color: var(--primary-color);
    transform: translateY(-3px);
}

/* LAYOUT CONTAINER */
.container {
    width: 90%;
    max-width: 1100px;
    margin: auto;
    padding: 2rem 0;
}

section { margin-bottom: 3rem; }
h2 { 
    border-bottom: 3px solid var(--primary-color);
    display: inline-block; 
    padding-bottom: 5px; 
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

/* SKILLS GRID */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 20px;
}

.skill-card {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
    border: 1px solid var(--border-color);
}

.skill-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

.skill-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.skill-card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin: 0;
    color: var(--text-color);
}

/* PROJECT CARDS */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.project-card {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    border: 1px solid var(--border-color);
}

.project-card:hover { 
    transform: translateY(-5px); 
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}
.project-card h3 { margin-top: 0; color: var(--text-color); }

.tech-stack { margin: 15px 0; }
.tag-small {
    background: var(--bg-color);
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    margin-right: 5px;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

/* BUTTONS */
.card-links { margin-top: auto; }
.btn {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    border-radius: 4px;
    font-size: 0.9rem;
    margin-right: 10px;
    transition: background 0.3s;
}
.btn:hover { background: var(--primary-hover); }
.btn.secondary { background: var(--secondary-btn); }
.btn.secondary:hover { background: var(--secondary-btn-hover); }

/* SPLIT SECTION (For Education & Experience) */
.split-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}
/* Mobile responsiveness */
@media (max-width: 768px) {
    .split-section { grid-template-columns: 1fr; }
}

/* TIMELINE STYLE */
.timeline-item {
    border-left: 3px solid var(--border-color);
    padding-left: 20px;
    margin-bottom: 20px;
    position: relative;
}
/* Blue dot on timeline */
.timeline-item::before {
    content: '';
    position: absolute;
    left: -9px;
    top: 5px;
    width: 15px;
    height: 15px;
    background: var(--primary-color);
    border-radius: 50%;
    border: 3px solid var(--card-bg);
}
.timeline-item h3 { margin: 0 0 5px 0; font-size: 1.1rem; color: var(--text-color); }
.timeline-item .date { color: var(--primary-color); font-size: 0.85rem; margin-bottom: 5px; font-weight: bold; }
.timeline-item p { margin: 0; color: var(--text-secondary); }

/* FOOTER */
footer { 
    text-align: center; 
    padding: 2rem; 
    color: var(--text-secondary);
    font-size: 0.9rem; 
    border-top: 1px solid var(--border-color);
    margin-top: 2rem;
}