:root {
    --primary-color: #3a6ea5;
    --secondary-color: #f5f5f5;
    --background-color: #121212;
    --text-color: #e0e1dd;
    --card-background: #1e1e1e;
    --font-family: 'Poppins', sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(30, 30, 30, 0.85);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
    z-index: 1000;
    transition: top 0.3s;
}

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

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

.navbar nav ul {
    display: flex;
    list-style: none;
}

.navbar nav ul li {
    margin-left: 2rem;
}

.navbar nav ul li a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.navbar nav ul li a:hover,
.navbar nav ul li a.active {
    color: var(--primary-color);
}

/* Hamburger Menu */
.hamburger {
    display: none;
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
}

/* Hero Section */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: linear-gradient(rgba(18, 18, 18, 0.7), rgba(18, 18, 18, 0.7)), url('./assets/img/hero.jpg') no-repeat center center/cover;
}

.hero h1 {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.hero .subtitle {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    color: var(--secondary-color);
}

.hero .btn {
    display: inline-block;
    padding: 0.8rem 2rem;
    background-color: var(--primary-color);
    color: #fff;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    transition: background-color 0.3s ease;
}

.hero .btn:hover {
    background-color: #2c5282;
}

/* General Section Styling */
section {
    padding: 6rem 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.section-subtitle {
    text-align: center;
    font-size: 1.2rem;
    margin-bottom: 4rem;
    color: var(--secondary-color);
}

/* About Section */
.about p {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    font-size: 1.1rem;
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 2rem;
    text-align: center;
}

.skill-card {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 10px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.skill-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(58, 110, 165, 0.2);
}

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

.skill-card span {
    font-weight: 500;
    margin-top: 0.5rem;
}

/* BTS SIO Section */
.options-container {
    display: flex;
    gap: 2rem;
    margin-top: 3rem;
}

.option-card {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 10px;
    flex: 1;
}

.option-card summary {
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    list-style: none;
}

.option-card summary::-webkit-details-marker {
    display: none;
}

.option-card p {
    margin-top: 1rem;
}

/* Projects Section */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.project-card {
    background-color: var(--card-background);
    border-radius: 10px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.project-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(58, 110, 165, 0.2);
}

.project-card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.project-info {
    padding: 1.5rem;
}

.project-info h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.project-info span {
    font-style: italic;
    color: var(--primary-color);
}

/* Experience Section */
.experience-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    max-width: 800px;
    margin: 0 auto;
}

.experience-card {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 10px;
}

.experience-card h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

/* Contact Section */
.contact {
    background-color: var(--card-background);
    padding: 4rem 0;
    text-align: center;
}

.contact-info {
    margin: 2rem 0;
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.contact-info a, .contact-info span {
    font-size: 1.1rem;
    text-decoration: none;
    color: var(--text-color);
    transition: color 0.3s ease;
}

.contact-info a:hover {
    color: var(--primary-color);
}

.contact-info i {
    margin-right: 0.5rem;
}

.email-contact {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    position: relative;
}

.copy-email-btn {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    font-size: 1rem;
    padding: 0.2rem;
}

.copy-email-btn:hover {
    color: var(--primary-color);
}

.social-links a {
    font-size: 2rem;
    margin: 0 1rem;
    color: var(--text-color);
    transition: color 0.3s ease;
}

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

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background-color: var(--primary-color);
    color: #fff;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s, background-color 0.3s;
    z-index: 1000;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background-color: #2c5282;
}

/* Reveal on Scroll Animation */
.reveal-on-scroll {
    opacity: 0;
    transform: translateY(50px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.reveal-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 768px) {
    .navbar .container {
        flex-direction: row;
        justify-content: space-between;
    }

    .navbar nav {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: rgba(30, 30, 30, 0.95);
        flex-direction: column;
        align-items: center;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.5s ease-out;
    }

    .navbar nav.active {
        max-height: 500px; /* Adjust as needed */
    }

    .navbar nav ul {
        flex-direction: column;
        width: 100%;
        padding: 1rem 0;
    }

    .navbar nav ul li {
        margin: 1rem 0;
        text-align: center;
    }

    .hamburger {
        display: block;
    }

    .hero h1 {
        font-size: 3rem;
    }

    .options-container {
        flex-direction: column;
    }
}