/* ==========================================================================
   Base Design Tokens & Custom Variables (Light Mode Default)
   ========================================================================== */
:root {
    /* Fonts */
    --font-primary: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Theme Colors (Light Mode) */
    --color-bg-primary: #f8fafc;     /* Clean slate-white */
    --color-bg-secondary: #ffffff;   /* Pure white */
    --color-bg-card: #ffffff;        /* Card background */
    --color-border: #e2e8f0;         /* Soft borders */
    
    --color-text-primary: #0f172a;   /* Deep Navy */
    --color-text-secondary: #475569; /* Slate Gray */
    --color-text-muted: #64748b;     /* Muted Gray */
    
    --color-brand-primary: #2563eb;  /* Clean Royal Blue */
    --color-brand-hover: #1d4ed8;    /* Darker Blue */
    --color-brand-light: #eff6ff;    /* Soft Blue Tint */
    
    --color-accent: #0284c7;         /* Sky Blue */
    --color-accent-hover: #0369a1;
    
    /* Layout Tokens */
    --header-height: 80px;
    --border-radius: 12px;
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.02);
}

/* ==========================================================================
   Dark Theme Configuration
   ========================================================================== */
body.dark-mode {
    --color-bg-primary: #0b0f19;     /* Midnight Navy */
    --color-bg-secondary: #111827;   /* Slate Black */
    --color-bg-card: #1e293b;        /* Dark Slate Blue */
    --color-border: #334155;         /* Muted Slate borders */
    
    --color-text-primary: #f8fafc;   /* Soft White */
    --color-text-secondary: #94a3b8; /* Cool Gray */
    --color-text-muted: #64748b;     /* Dim Gray */
    
    --color-brand-primary: #3b82f6;  /* Vibrant Blue */
    --color-brand-hover: #60a5fa;    /* Light sky blue hover */
    --color-brand-light: #1e3a8a;    /* Deep navy tint */
    
    --color-accent: #38bdf8;         /* Cyan Accent */
    --color-accent-hover: #7dd3fc;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
}

/* ==========================================================================
   Reset & Global Styles
   ========================================================================== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

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

/* Base Accessibility Focus */
*:focus-visible {
    outline: 3px solid var(--color-brand-primary);
    outline-offset: 3px;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Typography elements */
h1, h2, h3, h4 {
    font-weight: 700;
    line-height: 1.25;
    color: var(--color-text-primary);
}

p {
    color: var(--color-text-secondary);
}

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

/* ==========================================================================
   Common Layout Components (Buttons, Sections, Grid)
   ========================================================================== */
section {
    padding: 100px 0 80px 0;
}

.section-title {
    font-size: 2.25rem;
    position: relative;
    margin-bottom: 48px;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 60px;
    height: 4px;
    background-color: var(--color-brand-primary);
    border-radius: 2px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 500;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color var(--transition-fast), transform var(--transition-fast), border-color var(--transition-fast);
    border: none;
}

.btn-primary {
    background-color: var(--color-brand-primary);
    color: #ffffff;
}

.btn-primary:hover {
    background-color: var(--color-brand-hover);
    transform: translateY(-2px);
}

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

.btn-outline:hover {
    border-color: var(--color-brand-primary);
    background-color: var(--color-brand-light);
    color: var(--color-brand-primary);
    transform: translateY(-2px);
}

/* Icons Utilities */
.text-blue { color: #2563eb; }
.text-green { color: #16a34a; }
.text-orange { color: #ea580c; }
.text-cyan { color: #0284c7; }
.text-yellow { color: #d97706; }
.text-black { color: #1f2937; }

/* ==========================================================================
   Header and Navigation Styling
   ========================================================================== */
#main-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    z-index: 1000;
    display: flex;
    align-items: center;
    border-bottom: 1px solid var(--color-border);
    transition: background-color var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

/* Scroll status header changes */
#main-header.scrolled {
    background-color: rgba(var(--color-bg-secondary-rgb, 255, 255, 255), 0.85);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    height: 70px;
}
body.dark-mode #main-header.scrolled {
    background-color: rgba(11, 15, 25, 0.85);
}
body:not(.dark-mode) #main-header.scrolled {
    background-color: rgba(255, 255, 255, 0.85);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}
.logo-accent {
    color: var(--color-brand-primary);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-link {
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    position: relative;
    padding: 8px 0;
}

.nav-link:hover, .nav-link.active {
    color: var(--color-brand-primary);
}

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

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

.header-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

/* Theme Toggle Button */
.theme-btn {
    background: transparent;
    border: 1px solid var(--color-border);
    color: var(--color-text-primary);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.theme-btn:hover {
    background-color: var(--color-brand-light);
    border-color: var(--color-brand-primary);
    color: var(--color-brand-primary);
}

/* Mobile Toggle Hamburger */
.mobile-toggle-btn {
    display: none;
    background: transparent;
    border: none;
    color: var(--color-text-primary);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 4px;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: radial-gradient(circle at 10% 20%, var(--color-brand-light) 0%, transparent 40%);
}

.hero-container {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 48px;
    align-items: center;
}

.hero-content {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.hero-greeting {
    font-family: var(--font-mono);
    color: var(--color-brand-primary);
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 12px;
    display: block;
}

.hero-name {
    font-size: 3.5rem;
    letter-spacing: -1px;
    margin-bottom: 8px;
}

.hero-title {
    font-size: 2rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    margin-bottom: 24px;
    display: flex;
    align-items: center;
}

.text-accent {
    color: var(--color-brand-primary);
    font-weight: 600;
}

.typewriter-cursor {
    color: var(--color-brand-primary);
    animation: blink 0.75s step-end infinite;
    font-weight: 300;
}

@keyframes blink {
    from, to { color: transparent }
    50% { color: var(--color-brand-primary); }
}

.hero-lead {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    margin-bottom: 36px;
    max-width: 600px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

/* Dev Profile Code Card Card */
.hero-visual {
    display: flex;
    justify-content: flex-end;
}

.profile-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 420px;
    overflow: hidden;
    font-family: var(--font-mono);
}

.code-header {
    background-color: var(--color-bg-secondary);
    padding: 12px 16px;
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    gap: 8px;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    display: inline-block;
}
.dot.red { background-color: #ef4444; }
.dot.yellow { background-color: #f59e0b; }
.dot.green { background-color: #10b981; }

.card-title {
    color: var(--color-text-muted);
    font-size: 0.8rem;
    margin-left: auto;
}

.code-body {
    padding: 24px;
    font-size: 0.9rem;
    white-space: pre-wrap;
    background-color: var(--color-bg-card);
}

.code-body .key { color: var(--color-brand-primary); }
.code-body .val { color: var(--color-accent); }

/* ==========================================================================
   About & Education Section
   ========================================================================== */
.about-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 64px;
    align-items: start;
}

.about-text p {
    font-size: 1.1rem;
    margin-bottom: 20px;
}

.education-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: 32px;
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
}

.card-header-icon {
    font-size: 2rem;
    color: var(--color-brand-primary);
    margin-bottom: 16px;
}

.education-card h3 {
    font-size: 1.5rem;
    margin-bottom: 24px;
}

.education-details {
    border-left: 2px solid var(--color-border);
    padding-left: 20px;
    position: relative;
}

.education-details::before {
    content: '';
    position: absolute;
    left: -6px;
    top: 6px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: var(--color-brand-primary);
}

.university-name {
    font-size: 1.15rem;
    margin-bottom: 4px;
}

.degree-title {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    margin-bottom: 20px;
}

.edu-meta-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.edu-meta-item {
    display: flex;
    flex-direction: column;
}

.meta-label {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.meta-value {
    font-weight: 600;
    font-size: 1rem;
}

.highlight-gpa {
    color: var(--color-brand-primary);
}

/* ==========================================================================
   Skills Section
   ========================================================================== */
.skills-section {
    background-color: var(--color-bg-secondary);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
}

.skills-category-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: 32px;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.skills-category-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.category-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 16px;
}

.category-header i {
    font-size: 1.5rem;
    color: var(--color-brand-primary);
}

.category-header h3 {
    font-size: 1.25rem;
}

.skills-list {
    list-style: none;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.skills-list li {
    display: flex;
    align-items: center;
}

.skill-name {
    font-weight: 500;
    color: var(--color-text-secondary);
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.95rem;
}

.skill-name i {
    font-size: 1.1rem;
    width: 20px;
    text-align: center;
}

/* ==========================================================================
   Projects Section
   ========================================================================== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.project-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.project-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-brand-primary);
}

.project-info {
    padding: 32px;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.project-tag {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-brand-primary);
    background-color: var(--color-brand-light);
    padding: 4px 10px;
    border-radius: 20px;
}

.project-icon {
    font-size: 1.25rem;
    color: var(--color-text-muted);
}

.project-title {
    font-size: 1.35rem;
    margin-bottom: 12px;
}

.project-desc {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    margin-bottom: 24px;
    flex-grow: 1;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 24px;
}

.project-tech span {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--color-text-muted);
    background-color: var(--color-bg-primary);
    padding: 3px 8px;
    border-radius: 4px;
    border: 1px solid var(--color-border);
}

.project-links {
    display: flex;
    gap: 16px;
}

.project-links a {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-brand-primary);
}

.project-links a:hover {
    color: var(--color-brand-hover);
}

/* ==========================================================================
   Contact Section
   ========================================================================== */
.contact-section {
    background-color: var(--color-bg-secondary);
}

.contact-layout {
    max-width: 700px;
    margin: 0 auto;
}

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

.contact-info h3 {
    font-size: 1.5rem;
    margin-bottom: 12px;
}

.contact-subtext {
    font-size: 1.05rem;
    margin-bottom: 40px;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.contact-links-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

.contact-item-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: 24px;
    display: flex;
    align-items: center;
    gap: 20px;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.contact-item-card:hover {
    transform: translateY(-3px);
    border-color: var(--color-brand-primary);
    box-shadow: var(--shadow-md);
}

.icon-wrap {
    width: 48px;
    height: 48px;
    background-color: var(--color-brand-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    color: var(--color-brand-primary);
    flex-shrink: 0;
    transition: transform var(--transition-fast);
}

.contact-item-card:hover .icon-wrap {
    transform: scale(1.1);
}

.item-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
}

.item-label {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 2px;
}

.item-val {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--color-text-primary);
    word-break: break-all;
}

/* ==========================================================================
   Footer
   ========================================================================== */
footer {
    background-color: var(--color-bg-primary);
    padding: 40px 0;
    border-top: 1px solid var(--color-border);
}

.footer-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

footer p {
    font-size: 0.95rem;
    color: var(--color-text-muted);
}

.footer-socials {
    display: flex;
    gap: 20px;
}

.footer-socials a {
    color: var(--color-text-muted);
    font-size: 1.2rem;
}

.footer-socials a:hover {
    color: var(--color-brand-primary);
}

/* ==========================================================================
   Scroll-Reveal Animations (Intersection Observer)
   ========================================================================== */
.reveal-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity var(--transition-slow), transform var(--transition-slow);
}

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

/* Reveal Delays */
.delay-1 { transition-delay: 0.15s; }
.delay-2 { transition-delay: 0.3s; }
.delay-3 { transition-delay: 0.45s; }

/* ==========================================================================
   Back To Top Button
   ========================================================================== */
.back-to-top-btn {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: var(--color-brand-primary);
    color: #ffffff;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-normal), visibility var(--transition-normal), background-color var(--transition-fast), transform var(--transition-fast);
    z-index: 99;
}

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

.back-to-top-btn:hover {
    background-color: var(--color-brand-hover);
    transform: translateY(-3px);
}

/* ==========================================================================
   Responsive Design & Media Queries
   ========================================================================== */

/* Up to Tablet / Mobile Screen Layouts */
@media (max-width: 992px) {
    section {
        padding: 80px 0 60px 0;
    }

    .hero-container {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }

    .hero-content {
        align-items: center;
    }

    .hero-name {
        font-size: 2.75rem;
    }

    .hero-title {
        font-size: 1.6rem;
    }

    .hero-visual {
        justify-content: center;
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .education-card {
        max-width: 500px;
        margin: 0 auto;
        width: 100%;
    }
}

/* Navbar breakpoint for mobile */
@media (max-width: 768px) {
    /* Mobile header toggling styles */
    .mobile-toggle-btn {
        display: block;
        z-index: 1001;
    }

    #navbar {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background-color: var(--color-bg-secondary);
        border-left: 1px solid var(--color-border);
        padding: 100px 32px 40px 32px;
        box-shadow: var(--shadow-lg);
        transition: right var(--transition-normal);
        z-index: 999;
    }

    #navbar.open {
        right: 0;
    }

    .nav-links {
        flex-direction: column;
        gap: 24px;
    }

    .nav-link {
        font-size: 1.1rem;
        display: block;
    }
    
    .contact-links-grid {
        grid-template-columns: 1fr;
    }

    .footer-container {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-name {
        font-size: 2.25rem;
    }

    .hero-title {
        font-size: 1.35rem;
    }

    .hero-actions {
        width: 100%;
        flex-direction: column;
    }

    .hero-actions .btn {
        width: 100%;
        justify-content: center;
    }

    .skills-list {
        grid-template-columns: 1fr;
    }
}