/* base variables & configuration */
:root {
    /* Color Palette - Dark Navy Theme (Default) */
    --bg-color: #0A1128; /* Deep rich navy */
    --bg-color-alt: #0D1635; /* Slightly lighter navy for cards/sections */
    --text-color: #F8FAFC; /* White with slight blue tint */
    --text-muted: #94A3B8; /* Soft blue-gray for secondary text */
    --primary-color: #38BDF8; /* Soft bright blue accent */
    --primary-color-hover: #0EA5E9;
    --border-color: rgba(255, 255, 255, 0.1);
    --card-bg: rgba(255, 255, 255, 0.03);
    --card-hover-bg: rgba(255, 255, 255, 0.05);
    
    /* Typography */
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
    
    /* Spacing & Sizes */
    --container-width: 1200px;
    --section-padding: 100px 0;
    --nav-height: 80px;
    --border-radius: 16px;
    --transition-speed: 0.3s;
}

/* Light mode overrides */
[data-theme="light"] {
    --bg-color: #F8FAFC; /* Soft off-white */
    --bg-color-alt: #FFFFFF;
    --text-color: #0F172A; /* Dark slate */
    --text-muted: #475569;
    --primary-color: #0284C7; /* Deeper blue for contrast on light setup */
    --primary-color-hover: #0369A1;
    --border-color: rgba(0, 0, 0, 0.1);
    --card-bg: #FFFFFF;
    --card-hover-bg: #F1F5F9;
}

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

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-body);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 24px;
}

section {
    padding: var(--section-padding);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: 1.2;
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 3rem;
    text-align: center;
    position: relative;
    padding-bottom: 15px;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background-color: var(--primary-color);
    border-radius: 2px;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-speed);
}

ul {
    list-style: none;
}

/* Navbar */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--nav-height);
    background-color: rgba(10, 17, 40, 0.85); /* Default transparent navy */
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 1000;
    border-bottom: 1px solid transparent;
    transition: all var(--transition-speed);
}

[data-theme="light"] .header {
    background-color: rgba(248, 250, 252, 0.85);
}

.header.scrolled {
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    font-family: var(--font-heading);
    font-size: 1.7rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.logo span {
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    gap: 2.5rem;
}

.nav-link {
    font-size: 0.95rem;
    font-weight: 500;
    position: relative;
    color: var(--text-color);
    opacity: 0.8;
    transition: opacity var(--transition-speed);
}

.nav-link:hover {
    opacity: 1;
}

.nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -6px;
    left: 0;
    background-color: var(--primary-color);
    transition: width var(--transition-speed);
}

.nav-link:hover::after, .nav-link.active::after {
    width: 100%;
}

.nav-link.active {
    opacity: 1;
    color: var(--primary-color);
}

.nav-link.active::after {
    background-color: var(--primary-color);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.lang-toggle {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 6px 14px;
    border-radius: 20px;
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-speed);
}
.lang-toggle:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color var(--transition-speed);
    width: 36px;
    height: 36px;
    border-radius: 50%;
}

.theme-toggle:hover {
    color: var(--primary-color);
    background-color: var(--card-bg);
}

/* Hamburger for mobile */
.hamburger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    gap: 6px;
    z-index: 1001;
}

.hamburger .bar {
    width: 28px;
    height: 2px;
    background-color: var(--text-color);
    transition: all var(--transition-speed);
    border-radius: 2px;
}

/* Footer */
.footer {
    padding: 40px 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-color-alt);
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 14px 32px;
    border-radius: 30px;
    font-family: var(--font-body);
    font-weight: 500;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-speed);
    text-align: center;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    border: 2px solid var(--primary-color);
}

.btn-primary:hover {
    background-color: transparent;
    color: var(--primary-color);
}

.btn-secondary {
    background-color: transparent;
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* Responsive */
@media (max-width: 992px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 0;
        flex-direction: column;
        background-color: var(--bg-color);
        width: 100%;
        height: 100vh;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        justify-content: center;
        gap: 2rem;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-link {
        font-size: 1.5rem;
    }

    .hamburger {
        display: flex;
    }

    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
}

/* ----------------------------------- */
/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: var(--nav-height);
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-greeting {
    font-size: 1.2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-family: var(--font-heading);
    letter-spacing: 1px;
}

.hero-title {
    font-size: 4.5rem;
    line-height: 1.1;
    margin-bottom: 1.5rem;
}

.hero-title .highlight {
    color: var(--primary-color);
}

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

.hero-subtitles .subtitle {
    font-size: 1.4rem;
    color: var(--text-color);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.hero-subtitles .subtitle.secondary {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.hero-image-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.hero-image-wrapper::before {
    content: '';
    position: absolute;
    width: 450px;
    height: 450px;
    background: radial-gradient(circle, var(--primary-color) 0%, transparent 60%);
    opacity: 0.15;
    z-index: 0;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    border-radius: 50%;
}

.hero-image-placeholder {
    width: 380px;
    height: 380px;
    border-radius: 40px;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    overflow: hidden;
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
    transform: rotate(3deg);
    transition: transform var(--transition-speed);
}

.hero-image-placeholder:hover {
    transform: rotate(0deg) translateY(-10px);
}

.hero-image-placeholder img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* ----------------------------------- */
/* About Section */
.about {
    background-color: var(--card-bg);
    margin: 0 24px;
    border-radius: var(--border-radius);
    position: relative;
    border: 1px solid var(--border-color);
}

.about-text {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.15rem;
    color: var(--text-muted);
    text-align: center;
}

.about-text p {
    margin-bottom: 1.5rem;
    line-height: 1.8;
}

.about-text p:last-child {
    margin-bottom: 0;
}

/* Adjustments for responsiveness */
@media (max-width: 992px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .hero-image-wrapper {
        margin-top: 3rem;
    }
    
    .hero-title {
        font-size: 3.5rem;
    }
    
    .hero-image-placeholder {
        width: 300px;
        height: 300px;
    }
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 2.8rem;
    }
    .hero-subtitles .subtitle {
        font-size: 1.2rem;
    }
    .about {
        margin: 0;
        border-radius: 0;
        border-left: none;
        border-right: none;
    }
}

/* ----------------------------------- */
/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
}

.skill-category {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 2.5rem;
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}

.skill-category:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.category-title {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    text-align: center;
}

.skill-list {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
}

.skill-item {
    background-color: rgba(56, 189, 248, 0.1);
    color: var(--text-color);
    padding: 10px 20px;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 500;
    border: 1px solid rgba(56, 189, 248, 0.2);
    transition: all var(--transition-speed);
}

[data-theme="light"] .skill-item {
    background-color: rgba(2, 132, 199, 0.05);
    border: 1px solid rgba(2, 132, 199, 0.2);
}

.skill-item:hover {
    background-color: var(--primary-color);
    color: #fff;
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

/* ----------------------------------- */
/* Education Section */
.education-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 3rem;
    display: flex;
    align-items: center;
    gap: 3rem;
    max-width: 800px;
    margin: 0 auto;
    transition: transform var(--transition-speed);
}

.education-card:hover {
    transform: translateY(-5px);
    border-color: rgba(56, 189, 248, 0.3);
}

.edu-icon {
    width: 100px;
    height: 100px;
    background-color: rgba(56, 189, 248, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    flex-shrink: 0;
}

.edu-details h3 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.edu-program {
    font-size: 1.25rem;
    color: var(--text-color);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.edu-status {
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 1rem;
}

.edu-location {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-muted);
}

@media (max-width: 768px) {
    .skills-grid {
        grid-template-columns: 1fr;
    }
    .education-card {
        flex-direction: column;
        text-align: center;
        gap: 1.5rem;
        padding: 2rem;
    }
    .edu-location {
        justify-content: center;
    }
}

/* ----------------------------------- */
/* Projects Section */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.project-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 2.5rem 2rem;
    text-align: center;
    transition: transform var(--transition-speed), border-color var(--transition-speed);
}

.project-card:hover {
    transform: translateY(-10px);
    border-color: var(--primary-color);
}

.project-icon {
    width: 65px;
    height: 65px;
    margin: 0 auto 1.5rem;
    color: var(--primary-color);
    background-color: rgba(56, 189, 248, 0.1);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-title {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.project-desc {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* ----------------------------------- */
/* Interests Section */
.interests-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    justify-content: center;
    max-width: 900px;
    margin: 0 auto;
}

.interest-item {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 15px 30px;
    border-radius: 30px;
    font-size: 1.1rem;
    font-family: var(--font-heading);
    font-weight: 500;
    color: var(--text-color);
    transition: all var(--transition-speed);
    display: flex;
    align-items: center;
    cursor: default;
}

.interest-item:hover {
    color: var(--primary-color);
    border-color: var(--primary-color);
    box-shadow: 0 5px 15px rgba(56, 189, 248, 0.15);
    background-color: rgba(56, 189, 248, 0.05);
}

/* ----------------------------------- */
/* Resume Section */
.resume-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 4rem;
    max-width: 700px;
    margin: 0 auto;
}

.resume-card p {
    font-size: 1.15rem;
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.text-center {
    text-align: center;
}

/* ----------------------------------- */
/* Contact Section */
.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 3.5rem;
}

.contact-info h3 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.contact-info p {
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.contact-links {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.contact-links li a {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--text-color);
    font-size: 1.1rem;
    transition: color var(--transition-speed);
}

.contact-links li a svg {
    color: var(--primary-color);
}

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

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    width: 100%;
}

.form-control {
    width: 100%;
    background-color: rgba(0, 0, 0, 0.15);
    border: 1px solid var(--border-color);
    padding: 16px 20px;
    border-radius: 12px;
    color: var(--text-color);
    font-family: var(--font-body);
    font-size: 1rem;
    transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
}

[data-theme="light"] .form-control {
    background-color: #fff;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.2);
}

textarea.form-control {
    resize: vertical;
}

@media (max-width: 992px) {
    .contact-wrapper {
        grid-template-columns: 1fr;
        padding: 2rem;
    }
}

/* ----------------------------------- */
/* Animations */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}