/* Global Design System & Variables */
:root {
    /* Fonts */
    --font-primary: 'Inter', sans-serif;
    --font-heading: 'Plus Jakarta Sans', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    /* Spacing Base */
    --spacing-unit: 8px;
    --sidebar-width: 280px;

    /* Theme - Dark Mode (Default) */
    --background: #050811;
    --surface: #0c141d;
    --surface-dim: #070a12;
    --surface-container: #141c26;
    --surface-container-high: #1d2530;
    --surface-container-highest: #262f3a;
    
    --primary: #149DDD;
    --primary-glow: rgba(20, 157, 221, 0.15);
    --primary-container: #004c6e;
    --on-primary: #ffffff;
    
    --on-background: #dbe3f1;
    --on-surface: #dbe3f1;
    --on-surface-variant: #bec8d1;
    --outline: #88929b;
    --outline-variant: rgba(62, 72, 80, 0.4);
    
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 12px;
    --border-radius-full: 9999px;

    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Theme - Light Mode */
body.light-mode {
    --background: #f4f6f9;
    --surface: #ffffff;
    --surface-dim: #eef1f5;
    --surface-container: #f0f3f6;
    --surface-container-high: #e2e6eb;
    --surface-container-highest: #d4d9e0;
    
    --primary: #0070a8;
    --primary-glow: rgba(0, 112, 168, 0.1);
    --primary-container: #cce7ff;
    --on-primary: #ffffff;
    
    --on-background: #0d1520;
    --on-surface: #0d1520;
    --on-surface-variant: #4e5a65;
    --outline: #7a8690;
    --outline-variant: rgba(180, 188, 196, 0.4);
}

/* Reset and Core Styles */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-primary);
    background-color: var(--background);
    color: var(--on-background);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.6;
    display: flex;
    -webkit-font-smoothing: antialiased;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Mouse Atmospheric Ambient Glow Background Effect */
#ambient-glow {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
    background: radial-gradient(circle 800px at var(--mouse-x, 50%) var(--mouse-y, 50%), rgba(20, 157, 221, 0.05), transparent 80%);
    transition: background var(--transition-fast);
}

/* Typography Utilities */
.display-lg {
    font-family: var(--font-heading);
    font-size: 2.75rem;
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -0.02em;
    color: var(--on-surface);
}

.headline-lg {
    font-family: var(--font-heading);
    font-size: 1.85rem;
    font-weight: 700;
    line-height: 1.3;
    color: var(--on-surface);
}

.headline-md {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 600;
    line-height: 1.4;
    color: var(--on-surface);
}

.label-accent {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    color: var(--primary);
    text-transform: uppercase;
    display: block;
    margin-bottom: calc(var(--spacing-unit) * 1.5);
}

.text-gradient {
    background: linear-gradient(135deg, var(--primary) 0%, #a4e1ff 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.highlight {
    color: var(--on-surface);
    font-weight: 600;
}

/* Button & Link Utilities */
.btn-primary {
    background-color: var(--primary);
    color: var(--on-primary);
    border: none;
    padding: 12px 20px;
    font-family: var(--font-primary);
    font-weight: 600;
    font-size: 0.9rem;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.btn-primary:hover {
    filter: brightness(1.15);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--primary-glow);
}

.btn-primary:active {
    transform: translateY(0);
}

.icon-button {
    background: transparent;
    border: none;
    color: var(--on-surface-variant);
    cursor: pointer;
    width: 38px;
    height: 38px;
    border-radius: var(--border-radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.icon-button:hover {
    color: var(--primary);
    background-color: var(--outline-variant);
}

.link-action {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--primary);
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition-fast);
    margin-top: calc(var(--spacing-unit) * 2);
}

.link-action:hover {
    gap: 12px;
}

.link-action span.material-symbols-outlined {
    font-size: 1.1rem;
}

/* General Layout Containers */
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background-color: var(--surface-dim);
    border-right: 1px solid var(--outline-variant);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: calc(var(--spacing-unit) * 4);
    z-index: 100;
    transition: transform var(--transition-normal), background-color var(--transition-normal);
}

.main-content {
    margin-left: var(--sidebar-width);
    flex: 1;
    min-height: 100vh;
    padding: calc(var(--spacing-unit) * 6) calc(var(--spacing-unit) * 8);
    position: relative;
    z-index: 2;
    max-width: 1200px;
    width: calc(100% - var(--sidebar-width));
}

.mobile-header {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 64px;
    background-color: rgba(12, 20, 29, 0.85);
    backdrop-filter: blur(16px);
    border-b: 1px solid var(--outline-variant);
    padding: 0 calc(var(--spacing-unit) * 3);
    align-items: center;
    justify-content: space-between;
    z-index: 90;
}

body.light-mode .mobile-header {
    background-color: rgba(255, 255, 255, 0.85);
}

.mobile-header .logo {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
}

/* Sidebar Components */
.sidebar-logo {
    font-family: var(--font-heading);
    font-size: 2.25rem;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: calc(var(--spacing-unit) * 4);
}

.profile-info {
    margin-bottom: calc(var(--spacing-unit) * 4);
    padding-bottom: calc(var(--spacing-unit) * 3);
    border-bottom: 1px solid var(--outline-variant);
}

.profile-name {
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--on-surface);
}

.profile-title {
    font-size: 0.8rem;
    color: var(--on-surface-variant);
    margin-top: 4px;
}

.nav-menu {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 1.5);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 2);
    color: var(--on-surface-variant);
    text-decoration: none;
    font-weight: 500;
    padding: 10px 16px;
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
}

.nav-link:hover {
    color: var(--primary);
    background-color: rgba(20, 157, 221, 0.08);
}

.nav-link.active {
    color: var(--primary);
    background-color: rgba(20, 157, 221, 0.12);
    font-weight: 600;
    border-left: 3px solid var(--primary);
    border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
}

.resume-btn {
    width: 100%;
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.sidebar-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: calc(var(--spacing-unit) * 2);
    border-top: 1px solid var(--outline-variant);
}

.footer-copyright {
    font-size: 0.75rem;
    color: var(--on-surface-variant);
    opacity: 0.8;
}

/* Page Section Styles */
.section {
    display: none;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity var(--transition-normal) ease-out, transform var(--transition-normal) ease-out;
    padding-top: calc(var(--spacing-unit) * 2);
}

.section.active-section {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 6);
    opacity: 1;
    transform: translateY(0);
}

/* Card Component & Decorative Accents */
.card {
    background-color: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-md);
    padding: calc(var(--spacing-unit) * 4);
    position: relative;
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.hero-card {
    padding: calc(var(--spacing-unit) * 6);
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2.5);
}

/* Custom Corner Accents (Stitch Inspired) */
.decor-corner {
    position: absolute;
    width: 16px;
    height: 16px;
    border-color: var(--primary);
    border-style: solid;
    pointer-events: none;
}

.decor-corner.top-left {
    top: -4px;
    left: -4px;
    border-width: 2px 0 0 2px;
}

.decor-corner.bottom-right {
    bottom: -4px;
    right: -4px;
    border-width: 0 2px 2px 0;
}

.hero-subtitle {
    font-size: 1.15rem;
    color: var(--on-surface-variant);
    max-w: 800px;
    line-height: 1.7;
}

.social-links {
    display: flex;
    gap: calc(var(--spacing-unit) * 3);
    margin-top: calc(var(--spacing-unit) * 2);
}

.social-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--on-surface-variant);
    text-decoration: none;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    transition: color var(--transition-fast);
}

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

.social-link span.material-symbols-outlined {
    font-size: 1.25rem;
}

/* Bio Structure */
.bio-container {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2);
}

.bio-text {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2.5);
    color: var(--on-surface-variant);
    font-size: 1.05rem;
    line-height: 1.75;
}

.academic-badge {
    display: flex;
    align-items: stretch;
    background-color: var(--surface-container);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-md);
    overflow: hidden;
    max-width: 500px;
    margin-top: calc(var(--spacing-unit) * 2);
}

.badge-accent {
    width: 6px;
    background-color: var(--primary);
}

.badge-content {
    padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 3);
}

.badge-content h4 {
    color: var(--on-surface);
    font-size: 1rem;
    font-weight: 600;
}

.badge-sub {
    font-size: 0.8rem;
    color: var(--on-surface-variant);
    margin-top: 4px;
}

/* Section Header Styles */
.section-header {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-unit);
}

.section-desc {
    color: var(--on-surface-variant);
    font-size: 1.1rem;
    max-w: 700px;
}

/* Skills Cards & Grid */
.skills-category-group {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2);
}

.category-header {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 1.5);
}

.category-header span.material-symbols-outlined {
    color: var(--primary);
    font-size: 1.5rem;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
    gap: calc(var(--spacing-unit) * 2);
}

.skill-card {
    background-color: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-md);
    padding: calc(var(--spacing-unit) * 3);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    aspect-ratio: 1 / 1;
    text-align: center;
    cursor: default;
    transition: border-color var(--transition-fast), background-color var(--transition-fast), transform var(--transition-fast);
}

.skill-card:hover {
    border-color: var(--primary);
    background-color: var(--surface-container);
    transform: translateY(-3px);
}

.skill-icon {
    font-size: 2.5rem;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: calc(var(--spacing-unit) * 1.5);
    transition: transform var(--transition-fast);
}

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

.skill-card:hover .skill-icon {
    transform: scale(1.1);
}

.skill-name {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--on-surface);
}

/* Projects Filters & Grid */
.project-filters {
    display: flex;
    flex-wrap: wrap;
    gap: calc(var(--spacing-unit) * 1.5);
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.filter-btn {
    background-color: var(--surface-container);
    border: 1px solid var(--outline-variant);
    color: var(--on-surface-variant);
    padding: 8px 18px;
    font-family: var(--font-primary);
    font-weight: 500;
    font-size: 0.85rem;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.filter-btn.active {
    background-color: var(--primary);
    border-color: var(--primary);
    color: var(--on-primary);
    font-weight: 600;
    box-shadow: 0 4px 10px var(--primary-glow);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: calc(var(--spacing-unit) * 3);
}

.project-card {
    background-color: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-md);
    padding: calc(var(--spacing-unit) * 4);
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2);
    transition: border-color var(--transition-fast), transform var(--transition-fast), background-color var(--transition-fast);
    animation: fadeScale var(--transition-normal) ease-out forwards;
}

.project-card:hover {
    border-color: var(--primary);
    transform: translateY(-4px);
    background-color: var(--surface-container-high);
}

.project-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.project-year {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--primary);
    font-weight: 600;
}

.project-badge {
    font-size: 0.75rem;
    font-weight: 600;
    background-color: var(--surface-container);
    padding: 3px 8px;
    border-radius: var(--border-radius-sm);
    color: var(--on-surface-variant);
}

.project-badge.text-primary-glow {
    color: var(--primary);
    background-color: var(--primary-glow);
}

.project-title {
    font-size: 1.15rem;
    font-weight: 700;
}

.project-desc {
    font-size: 0.9rem;
    color: var(--on-surface-variant);
    line-height: 1.5;
}

.project-highlights {
    list-style-type: none;
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--on-surface-variant);
    padding-left: 0;
    margin-top: calc(var(--spacing-unit) * 0.5);
    flex-grow: 1;
}

.project-highlights li {
    position: relative;
    padding-left: 16px;
}

.project-highlights li::before {
    content: "•";
    color: var(--primary);
    font-weight: bold;
    position: absolute;
    left: 4px;
}

.project-tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: calc(var(--spacing-unit) * 1.5);
    padding-top: calc(var(--spacing-unit) * 1.5);
    border-top: 1px solid var(--outline-variant);
}

.project-tech-tags span {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--on-surface-variant);
    background-color: var(--surface-container-high);
    padding: 3px 8px;
    border-radius: var(--border-radius-sm);
}

/* User Manual Styles (SWOT style cards) */
.swot-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: calc(var(--spacing-unit) * 3);
}

.swot-card {
    background-color: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-md);
    padding: calc(var(--spacing-unit) * 3.5);
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2);
    transition: all var(--transition-fast);
}

.swot-card:hover {
    border-color: rgba(20, 157, 221, 0.4);
    background-color: var(--surface-container);
}

.swot-header {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 1.5);
}

.text-emoji {
    font-size: 1.5rem;
}

.swot-text {
    font-size: 0.9rem;
    color: var(--on-surface-variant);
    line-height: 1.6;
}

/* Quotes block and certifications */
.quote-certifications-row {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: calc(var(--spacing-unit) * 4);
    margin-top: calc(var(--spacing-unit) * 2);
}

.quotes-block {
    background-color: var(--surface-container-high);
    border-left: 4px solid var(--primary);
    border-radius: 0 var(--border-radius-md) var(--border-radius-md) 0;
    padding: calc(var(--spacing-unit) * 4);
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.quote-mark {
    position: absolute;
    top: 10px;
    right: 24px;
    font-family: Georgia, serif;
    font-size: 5rem;
    color: var(--primary);
    opacity: 0.08;
    line-height: 1;
}

.quote-content {
    font-size: 1.15rem;
    font-style: italic;
    color: var(--on-surface);
    line-height: 1.6;
    margin-bottom: calc(var(--spacing-unit) * 1.5);
}

.quote-author {
    font-weight: 700;
    color: var(--primary);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.certifications-block {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2.5);
}

.cert-item {
    display: flex;
    gap: calc(var(--spacing-unit) * 2);
    align-items: center;
    background-color: var(--surface);
    border: 1px solid var(--outline-variant);
    padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 3);
    border-radius: var(--border-radius-md);
}

.cert-indicator {
    width: 8px;
    height: 8px;
    background-color: var(--primary);
    border-radius: var(--border-radius-full);
}

.cert-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--on-surface);
}

.cert-issuer {
    font-size: 0.75rem;
    color: var(--on-surface-variant);
    margin-top: 2px;
}

/* Contact Page Grid & Communication Channels */
.grid-2 {
    display: grid;
    grid-template-columns: 1.1fr 1fr;
    gap: calc(var(--spacing-unit) * 8);
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 4);
}

.text-link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

.text-link:hover {
    text-decoration: underline;
}

.contact-channels {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 3);
    margin-top: calc(var(--spacing-unit) * 2);
}

.channel {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 2);
    background-color: var(--surface);
    border: 1px solid var(--outline-variant);
    padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 3);
    border-radius: var(--border-radius-md);
}

.channel span.material-symbols-outlined {
    color: var(--primary);
    font-size: 1.4rem;
}

.channel label {
    display: block;
    font-size: 0.7rem;
    color: var(--on-surface-variant);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.channel span:not(.material-symbols-outlined), .channel a {
    font-size: 0.95rem;
    color: var(--on-surface);
    font-weight: 600;
    text-decoration: none;
}

.contact-icons {
    display: flex;
    gap: calc(var(--spacing-unit) * 2);
    margin-top: calc(var(--spacing-unit) * 2);
}

.contact-icons a {
    width: 46px;
    height: 46px;
    border-radius: var(--border-radius-md);
    border: 1px solid var(--outline-variant);
    background-color: var(--surface);
    color: var(--on-surface-variant);
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    transition: all var(--transition-fast);
}

.contact-icons a:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-2px);
}

/* Contact Card Centering Styles */
.contact-card-container {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    margin: 0 auto;
    max-width: 600px;
}

.contact-card {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 3.5);
    padding: calc(var(--spacing-unit) * 6) !important;
}

/* Animations */
@keyframes fadeScale {
    from {
        opacity: 0;
        transform: scale(0.97);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* Responsive Breakpoints */
@media (max-width: 1023px) {
    body {
        flex-direction: column;
    }
    
    .sidebar {
        transform: translateX(-100%);
        height: 100vh;
        top: 64px;
        box-shadow: 10px 0 30px rgba(0, 0, 0, 0.15);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
        width: 100%;
        padding: calc(var(--spacing-unit) * 4);
        padding-top: 96px;
    }
    
    .mobile-header {
        display: flex;
    }
}

@media (max-width: 768px) {
    .display-lg {
        font-size: 2.25rem;
    }
    
    .quote-certifications-row {
        grid-template-columns: 1fr;
    }
    
    .grid-2 {
        grid-template-columns: 1fr;
        gap: calc(var(--spacing-unit) * 6);
    }
}