:root {
    --primary-color: #20c997; /* Vibrant Teal/Mint */
    --secondary-color: #343a40; /* Dark Slate Gray */
    --accent-color: #ff8c00; /* Dark Orange */
    --light-bg: #ffffff;
    --alt-light-bg: #f8f9fa; /* Slightly off-white for alternating sections */
    --text-color: #212529; /* Darker text */
    --muted-text-color: #6c757d;
    --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    --card-hover-shadow: 0 15px 35px rgba(0, 0, 0, 0.12);
    --border-radius: 8px;
    --transition-speed: 0.3s;
    --font-primary: 'Poppins', sans-serif;
    --font-secondary: 'Roboto Slab', serif;
}

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

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

body {
    font-family: var(--font-primary);
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--light-bg);
    overflow-x: hidden; /* Prevent horizontal scroll from animations */
}

.container {
    max-width: 1140px;
    margin: 0 auto;
    padding: 0 20px;
}

/* --- Header & Navigation --- */
#main-header {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.05);
    transition: background-color var(--transition-speed) ease;
}

#main-header.scrolled {
    background-color: rgba(255, 255, 255, 0.98);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

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

nav .logo {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--secondary-color);
    text-decoration: none;
    font-family: var(--font-secondary);
}

nav ul {
    list-style: none;
    display: flex;
    align-items: center;
}

nav ul li {
    margin-left: 25px;
}

nav ul li a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 500;
    padding: 8px 12px;
    border-radius: var(--border-radius);
    transition: color var(--transition-speed) ease, background-color var(--transition-speed) ease;
    position: relative;
}
nav ul li a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary-color);
    transition: width var(--transition-speed) ease;
}

nav ul li a:hover, nav ul li a.active {
    color: var(--primary-color);
}
nav ul li a:hover::after, nav ul li a.active::after {
    width: 70%;
}


nav .nav-resume-btn {
    background-color: var(--primary-color);
    color: white;
    padding: 10px 20px;
    border-radius: 50px; /* Pill shape */
    transition: background-color var(--transition-speed) ease, transform var(--transition-speed) ease;
}
nav .nav-resume-btn:hover {
    background-color: #1baa80; /* Darker primary */
    transform: translateY(-2px);
    color: white !important; /* Ensure text color remains white */
}
nav .nav-resume-btn:hover::after {
    width: 0; /* No underline for button */
}


.menu-toggle {
    display: none;
    cursor: pointer;
    z-index: 1001; /* Above nav ul for mobile */
}

.hamburger {
    width: 25px;
    height: 20px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.hamburger span {
    display: block;
    height: 3px;
    width: 100%;
    background: var(--secondary-color);
    border-radius: 10px;
    transition: all var(--transition-speed) ease-in-out;
}
.menu-toggle.open .hamburger span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}
.menu-toggle.open .hamburger span:nth-child(2) {
    opacity: 0;
}
.menu-toggle.open .hamburger span:nth-child(3) {
    transform: translateY(-9px) rotate(-45deg);
}


/* --- Hero Section --- */
#hero {
    background: url('https://images.unsplash.com/photo-1498050108023-c5249f4df085?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1744&q=80') no-repeat center center/cover;
    /* Consider a more abstract tech background if preferred */
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    position: relative;
    padding-top: 80px; /* Header height */
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, rgba(32, 201, 151, 0.7), rgba(52, 58, 64, 0.8));
    /* primary to secondary gradient */
}

.hero-content {
    position: relative;
    z-index: 1;
    color: white;
}

#hero h1 {
    font-size: 3.5rem;
    font-family: var(--font-secondary);
    margin-bottom: 0.8rem;
    font-weight: 700;
    letter-spacing: 1px;
}

#hero .subtitle {
    font-size: 1.6rem;
    font-family: var(--font-primary);
    margin-bottom: 0.8rem;
    font-weight: 400;
    opacity: 0.9;
}
#hero .location {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    font-style: italic;
    opacity: 0.8;
}

.cta-button {
    display: inline-flex; /* For aligning text and arrow */
    align-items: center;
    background-color: var(--accent-color);
    color: white;
    padding: 14px 30px;
    text-decoration: none;
    border-radius: 50px; /* Pill shape */
    font-size: 1.1rem;
    font-weight: 600;
    transition: background-color var(--transition-speed) ease, transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
.cta-button .arrow {
    margin-left: 8px;
    transition: transform var(--transition-speed) ease;
}
.cta-button:hover {
    background-color: #e67e00; /* Darker accent */
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.15);
}
.cta-button:hover .arrow {
    transform: translateX(5px);
}

.cta-button-secondary {
    display: inline-block;
    background-color: transparent;
    color: var(--primary-color);
    padding: 12px 25px;
    text-decoration: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    border: 2px solid var(--primary-color);
    transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease, transform var(--transition-speed) ease;
    margin-top: 1rem;
}
.cta-button-secondary:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}


/* --- General Section Styling --- */
.content-section {
    padding: 80px 0;
}
.content-section.alt-bg {
    background-color: var(--alt-light-bg);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-family: var(--font-secondary);
    margin-bottom: 60px;
    color: var(--secondary-color);
    position: relative;
    padding-bottom: 15px;
}
.section-title::after {
    content: '';
    display: block;
    width: 70px;
    height: 4px;
    background-color: var(--primary-color);
    margin: 10px auto 0;
    border-radius: 2px;
}

/* --- About Section --- */
#about .about-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr; /* Adjust ratio as needed */
    gap: 50px;
    align-items: center;
}
#about .about-image-container {
    text-align: center;
}
#about .profile-pic {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    border: 5px solid white; /* Frame effect */
}
#about .about-text p {
    margin-bottom: 1.2rem;
    font-size: 1.05rem;
    color: var(--muted-text-color);
}
#about .about-text p strong {
    color: var(--text-color);
    font-weight: 600;
}
#about .elevator-pitch {
    margin-top: 2rem;
    padding: 1.5rem;
    background-color: var(--alt-light-bg);
    border-left: 4px solid var(--primary-color);
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
}
#about .elevator-pitch h3 {
    color: var(--secondary-color);
    font-family: var(--font-primary);
    font-weight: 600;
    margin-bottom: 0.8rem;
}
#about .elevator-pitch ul {
    list-style: none; /* Remove default bullets */
    padding-left: 0;
}
#about .elevator-pitch ul li {
    margin-bottom: 0.5rem;
    color: var(--muted-text-color);
    position: relative;
    padding-left: 20px; /* Space for custom bullet */
}
#about .elevator-pitch ul li::before {
    content: '✓'; /* Checkmark or other icon */
    color: var(--primary-color);
    position: absolute;
    left: 0;
    font-weight: bold;
}


/* --- Experience Section (Timeline) --- */
.experience-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}
.experience-timeline::after { /* The central line */
    content: '';
    position: absolute;
    width: 4px;
    background-color: var(--primary-color);
    opacity: 0.3;
    top: 0;
    bottom: 0;
    left: 50%;
    margin-left: -2px; /* Half of its width */
}
.experience-item {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
    width: 50%;
}
.experience-item .experience-dot { /* The circles on the timeline */
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    right: -8px; /* Adjust to sit on the line */
    background-color: white;
    border: 4px solid var(--primary-color);
    top: 28px; /* Align with heading */
    border-radius: 50%;
    z-index: 1;
}
/* Place items to the left */
.experience-item:nth-child(odd) {
    left: 0;
}
/* Place items to the right */
.experience-item:nth-child(even) {
    left: 50%;
}
/* Fix dot position for right-sided items */
.experience-item:nth-child(even) .experience-dot {
    left: -8px; /* Adjust to sit on the line */
}

.experience-content {
    padding: 20px 30px;
    background-color: white;
    position: relative;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
}
.experience-content:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-hover-shadow);
}
.experience-content h3 {
    color: var(--primary-color);
    font-family: var(--font-primary);
    font-weight: 600;
    margin-bottom: 5px;
    font-size: 1.25rem;
}
.experience-content .company-date {
    font-size: 0.9rem;
    color: var(--muted-text-color);
    margin-bottom: 10px;
    font-style: italic;
}
.experience-content .company-date strong {
    color: var(--secondary-color);
    font-style: normal;
}
.experience-content ul {
    list-style: none;
    padding-left: 0;
}
.experience-content ul li {
    margin-bottom: 8px;
    font-size: 0.95rem;
    color: var(--muted-text-color);
    position: relative;
    padding-left: 20px;
}
.experience-content ul li::before {
    content: '›';
    color: var(--accent-color);
    position: absolute;
    left: 0;
    font-weight: bold;
    font-size: 1.2em;
    top: -2px;
}


/* --- Skills Section --- */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}
.skills-category {
    background-color: var(--light-bg);
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
}
.skills-category:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-hover-shadow);
}
.skills-category h4 {
    font-size: 1.3rem;
    font-family: var(--font-primary);
    font-weight: 600;
    color: var(--secondary-color);
    margin-bottom: 20px;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 8px;
    display: inline-block;
}
.skills-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}
.skill-tag {
    background-color: var(--primary-color);
    color: white;
    padding: 8px 18px;
    border-radius: 20px; /* Pill shape */
    font-size: 0.9rem;
    font-weight: 500;
    transition: background-color var(--transition-speed) ease, transform var(--transition-speed) ease;
}
.skill-tag:hover {
    background-color: #1baa80; /* Darker primary */
    transform: scale(1.05);
}

/* --- Courses Section --- */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}
.course-item {
    background-color: white;
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    text-align: center;
    transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
}
.course-item:hover {
    transform: translateY(-8px);
    box-shadow: var(--card-hover-shadow);
}
.course-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}
.course-item h3 {
    color: var(--secondary-color);
    font-family: var(--font-primary);
    font-weight: 600;
    margin-bottom: 10px;
    font-size: 1.25rem;
}
.course-item p {
    font-size: 0.95rem;
    color: var(--muted-text-color);
}

/* --- Footer --- */
#main-footer {
    background-color: var(--secondary-color);
    color: #adb5bd; /* Lighter grey for footer text */
    text-align: center;
    padding: 40px 20px;
    font-size: 0.9rem;
}
#main-footer p {
    margin-bottom: 8px;
}
#main-footer a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color var(--transition-speed) ease;
}
#main-footer a:hover {
    color: #1baa80; /* Darker primary */
    text-decoration: underline;
}

/* --- Scroll Animation Classes --- */
.animate-on-scroll {
    opacity: 0;
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
    transition-delay: var(--delay, 0s); /* Custom delay per element */
}
.animate-on-scroll.is-visible {
    opacity: 1;
    transform: none !important; /* Override initial transform */
}
.fade-in { transform: translateY(20px); }
.fade-in-up { transform: translateY(50px); }
.fade-in-left { transform: translateX(-50px); }
.fade-in-right { transform: translateX(50px); }
.slide-in-left { transform: translateX(-100px); } /* For timeline */
.slide-in-right { transform: translateX(100px); } /* For timeline */


/* --- Responsive Design --- */
@media (max-width: 992px) {
    #hero h1 { font-size: 3rem; }
    #hero .subtitle { font-size: 1.4rem; }
    .section-title { font-size: 2.2rem; }
    #about .about-grid { grid-template-columns: 1fr; }
    #about .about-image-container { margin-bottom: 30px; max-width: 300px; margin-left:auto; margin-right:auto; }
}

@media (max-width: 768px) {
    html { font-size: 15px; }
    #main-header { padding: 0.8rem 0; }
    nav ul {
        display: none;
        flex-direction: column;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: white;
        padding-top: 80px; /* Space for logo/close button */
        text-align: center;
        transform: translateX(100%);
        transition: transform var(--transition-speed) ease-in-out;
    }
    nav ul.active {
        display: flex;
        transform: translateX(0);
    }
    nav ul li {
        margin: 20px 0;
    }
    nav ul li a {
        font-size: 1.2rem;
        color: var(--secondary-color); /* Ensure visibility on white bg */
    }
    nav .nav-resume-btn {
        margin-top: 20px;
        padding: 12px 25px;
    }
    .menu-toggle {
        display: block; /* Show hamburger */
    }

    #hero { min-height: 80vh; }
    #hero h1 { font-size: 2.5rem; }
    #hero .subtitle { font-size: 1.2rem; }

    /* Timeline adjustments for mobile */
    .experience-timeline::after {
        left: 31px; /* Move line to the left */
    }
    .experience-item {
        width: 100%;
        padding-left: 70px; /* Space for dot and line */
        padding-right: 15px;
    }
    .experience-item:nth-child(odd), .experience-item:nth-child(even) {
        left: 0;
    }
    .experience-item .experience-dot {
        left: 23px; /* Align dot with the line */
        right: auto;
    }
    /* Make sure right-sided item content doesn't get cut off */
     .experience-item:nth-child(even) .experience-content {
        /* No specific change needed if padding is correct */
    }
    .slide-in-left, .slide-in-right { transform: translateY(50px); } /* Change animation for mobile timeline */

}

@media (max-width: 576px) {
    #hero h1 { font-size: 2rem; }
    #hero .subtitle { font-size: 1rem; }
    .cta-button { padding: 12px 25px; font-size: 1rem; }
    .section-title { font-size: 1.8rem; margin-bottom: 40px; }
    .content-section { padding: 60px 0; }
    #about .about-grid { gap: 30px; }
    .skills-grid { grid-template-columns: 1fr; } /* Stack skills categories */
    .courses-grid { grid-template-columns: 1fr; } /* Stack courses */
}