:root {
    --color-bg: #F8FAFC; 
    --color-grid: rgba(56, 189, 248, 0.25);
    --color-surface: rgba(255, 255, 255, 0.85);
    --color-text-primary: #0F172A; 
    --color-text-secondary: #475569;
    --color-text-muted: #64748B;
    --color-border: #38BDF8;
    --color-border-hover: #0284C7;
    --color-accent: #0284C7; 

    --space-1: 0.25rem; --space-2: 0.5rem; --space-3: 0.75rem;
    --space-4: 1rem; --space-6: 1.5rem; --space-8: 2rem;
    --space-12: 3rem; --space-16: 4rem; --space-24: 6rem;

    --font-sans: 'Inter', system-ui, sans-serif;
    --font-mono: 'Fira Code', 'Courier New', monospace;
    
    --container-width: 800px;
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --duration-fast: 150ms; --duration-base: 300ms; --duration-slow: 700ms;
    
    --radius-sm: 2px; --radius-md: 4px; --radius-lg: 6px;
}

html.theme-dark {
    --color-bg: #091124; 
    --color-grid: rgba(56, 189, 248, 0.12); 
    --color-surface: rgba(9, 17, 36, 0.65); 
    --color-text-primary: #F8FAFC;
    --color-text-secondary: #94A3B8;
    --color-text-muted: #475569;
    --color-border: rgba(56, 189, 248, 0.4); 
    --color-border-hover: rgba(56, 189, 248, 1);
    --color-accent: #38BDF8; 
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
    font-family: var(--font-sans); 
    background-color: var(--color-bg);
    color: var(--color-text-primary); line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    transition: background-color var(--duration-base) var(--ease-out), color var(--duration-base) var(--ease-out);
    overflow-x: clip;
    
    background-image: 
        linear-gradient(var(--color-grid) 1px, transparent 1px),
        linear-gradient(90deg, var(--color-grid) 1px, transparent 1px);
    background-size: 32px 32px;
    background-position: center top;
    background-attachment: fixed;
}

::selection { background-color: var(--color-accent); color: #000; }
.mono-text { font-family: var(--font-mono); text-transform: uppercase; }

/* ── Scroll Progress Bar ── */
.scroll-progress-bar {
    position: fixed; top: 0; left: 0; height: 3px;
    background-color: var(--color-accent);
    box-shadow: 0 0 10px var(--color-accent);
    z-index: 100; width: 0%;
    transition: width 0.1s ease-out;
}

/* ── Skip Link (Accessibility) ── */
.skip-link {
    position: absolute; top: -40px; left: 0;
    background: var(--color-accent); color: #000;
    padding: var(--space-2) var(--space-4); z-index: 90;
    font-family: var(--font-mono);
}
.skip-link:focus { top: 0; }

/* ── Layout ── */
.main-container { max-width: var(--container-width); margin: 0 auto; padding: 0 var(--space-6); }
.section { margin-bottom: var(--space-16); }

/* ── Navbar ── */
.navbar-wrapper {
    position: fixed; top: var(--space-4); left: 0; width: 100%;
    display: flex; justify-content: center; z-index: 50; pointer-events: none;
    padding: 0 var(--space-6);
}
.navbar {
    pointer-events: auto; 
    display: flex; flex-direction: row; align-items: center; justify-content: space-between; 
    background: var(--color-surface);
    backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--color-border); 
    border-radius: var(--radius-md); 
    padding: var(--space-2) var(--space-4); 
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    width: 100%; 
    max-width: var(--container-width);
}

.logo-wrapper { display: flex; flex-direction: row; align-items: center; gap: var(--space-3); flex-shrink: 0; }
.nav-logo-image {
    width: 24px; height: 24px; border-radius: 2px;
    object-fit: cover; filter: grayscale(100%) sepia(100%) hue-rotate(180deg);
    border: 1px solid var(--color-accent);
}
.logo-wrapper:hover .nav-logo-image { filter: none; border-color: transparent; }
.logo-text { font-family: var(--font-mono); font-weight: 600; font-size: 0.875rem; letter-spacing: 0.05em; color: var(--color-accent); }

.nav-right { display: flex; flex-direction: row; align-items: center; gap: var(--space-4); }

.nav-menu { 
    display: flex; flex-direction: row; align-items: center; gap: var(--space-1); 
}
.nav-link {
    font-family: var(--font-mono); font-size: 0.75rem; font-weight: 500; 
    color: var(--color-text-secondary); text-decoration: none; 
    padding: var(--space-1) var(--space-2); border-radius: var(--radius-sm); 
    transition: color var(--duration-fast) var(--ease-out),
                background var(--duration-fast) var(--ease-out),
                border-color var(--duration-fast) var(--ease-out),
                box-shadow var(--duration-fast) var(--ease-out);
    white-space: nowrap;
    border: 1px solid transparent;
}
.nav-link:hover { color: var(--color-accent); background: rgba(56, 189, 248, 0.1); border-color: rgba(56, 189, 248, 0.3); }
.nav-link.active { color: var(--color-accent); background: rgba(56, 189, 248, 0.15); border-color: var(--color-accent); box-shadow: 0 0 10px rgba(56, 189, 248, 0.2); }
.nav-link:active { transform: scale(0.92); }

/* ── Section Highlight Flash ── */
.section-highlight {
    animation: highlightFlash 1.2s ease-out forwards;
}

@keyframes highlightFlash {
    0% { background-color: transparent; }
    30% { background-color: rgba(56, 189, 248, 0.1); box-shadow: 0 0 30px rgba(56, 189, 248, 0.15); border-radius: var(--radius-md); }
    100% { background-color: transparent; }
}

/* ── Theme Toggle ── */
.theme-toggle {
    background: transparent; border: 1px solid var(--color-border);
    color: var(--color-accent); cursor: pointer;
    width: 32px; height: 32px; border-radius: var(--radius-sm);
    display: flex; align-items: center; justify-content: center; flex-shrink: 0;
    transition: all var(--duration-fast) var(--ease-out);
}
.theme-toggle:hover { background-color: var(--color-accent); color: #000; }
html:not(.theme-dark) .sun-icon { display: none; }
html.theme-dark .moon-icon { display: none; }

/* ── Hero ── */
.hero { margin-top: 24vh; margin-bottom: var(--space-24); text-align: left; display: flex; flex-direction: column; align-items: flex-start; }
.hero-badge {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 4px 12px; background: rgba(56, 189, 248, 0.1); 
    border: 1px solid var(--color-border); border-radius: var(--radius-sm); 
    font-size: 0.75rem; color: var(--color-accent); margin-bottom: var(--space-6);
}
.pulse-dot { width: 6px; height: 6px; background: var(--color-accent); border-radius: 0; animation: pulse 2s infinite; }
@keyframes pulse { 0% { opacity: 1; } 50% { opacity: 0.2; } 100% { opacity: 1; } }

.text-accent { color: var(--color-accent); }

.hero-title { font-size: clamp(2rem, 5vw, 3.8rem); font-weight: 700; line-height: 1.15; margin-bottom: var(--space-6); letter-spacing: -0.02em; }
.hero-bio { font-size: 1.125rem; color: var(--color-text-secondary); max-width: 650px; margin-bottom: var(--space-8); line-height: 1.7; border-left: 2px solid var(--color-border); padding-left: var(--space-4); }
.hero-actions { display: flex; gap: var(--space-4); flex-wrap: wrap; }

/* ── Buttons ── */
.btn {
    padding: var(--space-3) var(--space-6); border-radius: var(--radius-sm);
    font-size: 0.8125rem; font-weight: 600; text-decoration: none;
    transition: all var(--duration-fast) var(--ease-out);
}
.btn-primary { background: rgba(56, 189, 248, 0.1); color: var(--color-accent); border: 1px solid var(--color-accent); box-shadow: inset 0 0 10px rgba(56, 189, 248, 0.1); }
.btn-primary:hover { background: var(--color-accent); color: #000; box-shadow: 0 0 15px var(--color-accent); }
.btn-secondary { background: transparent; color: var(--color-text-primary); border: 1px dashed var(--color-border); }
.btn-secondary:hover { border-style: solid; border-color: var(--color-accent); color: var(--color-accent); }

/* ── Section Title ── */
.section-title {
    font-family: var(--font-mono); font-size: 0.875rem; font-weight: 500; 
    color: var(--color-accent); margin-bottom: var(--space-8); 
    display: inline-block; border-bottom: 1px solid var(--color-border); padding-bottom: 4px;
}

/* ── Bento Grid ── */
.bento-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--space-4); }
.schematic-panel {
    background: var(--color-surface); 
    backdrop-filter: blur(4px); -webkit-backdrop-filter: blur(4px);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md); padding: var(--space-8);
    display: flex; flex-direction: column; 
    position: relative;
    transition: border-color var(--duration-base) var(--ease-out),
                background var(--duration-base) var(--ease-out),
                box-shadow var(--duration-base) var(--ease-out),
                transform var(--duration-base) var(--ease-out);
}
.schematic-panel::before, .schematic-panel::after {
    content: ''; position: absolute; width: 10px; height: 10px; border: 2px solid var(--color-accent); opacity: 0; transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}
.schematic-panel::before { top: 0; left: 0; border-right: none; border-bottom: none; transform: translate(-4px, -4px); }
.schematic-panel::after { bottom: 0; right: 0; border-left: none; border-top: none; transform: translate(4px, 4px); }
.schematic-panel:hover::before { opacity: 1; transform: translate(-2px, -2px); }
.schematic-panel:hover::after { opacity: 1; transform: translate(2px, 2px); }

.schematic-panel:hover { 
    border-color: var(--color-border-hover); 
    background: rgba(56, 189, 248, 0.05);
    box-shadow: 0 8px 30px rgba(56, 189, 248, 0.15);
    transform: translateY(-4px);
}

/* ── Glow Text ── */
.glow-text {
    position: relative;
    display: inline-block;
    animation: textPulse 2.5s infinite alternate;
}
@keyframes textPulse {
    0% { text-shadow: 0 0 2px rgba(56,189,248,0.2); }
    100% { text-shadow: 0 0 10px rgba(56,189,248,0.6), 0 0 20px rgba(56,189,248,0.4); }
}
.bento-large { grid-column: 1 / -1; }

/* ── Bento Content ── */
.bento-meta { font-size: 0.75rem; color: var(--color-text-muted); margin-bottom: var(--space-4); }
.bento-title { font-size: 1.125rem; font-weight: 600; color: var(--color-text-primary); margin-bottom: 4px; }
.bento-subtitle { font-size: 0.875rem; color: var(--color-text-secondary); margin-bottom: var(--space-4); font-weight: 400; }
.bento-desc { font-size: 0.9375rem; color: var(--color-text-secondary); line-height: 1.6; }

/* ── Skills ── */
.skills-wrapper { display: flex; flex-wrap: wrap; gap: var(--space-8); }
.skill-category { flex: 1; min-width: 200px; }
.skill-title { font-size: 0.75rem; color: var(--color-accent); margin-bottom: var(--space-4); opacity: 0.8; }
.skill-list { list-style: none; display: flex; flex-wrap: wrap; gap: var(--space-2); }
.skill-list li {
    font-size: 0.75rem; color: var(--color-text-secondary);
    background-color: transparent; border: 1px solid var(--color-border);
    padding: 4px 8px; border-radius: var(--radius-sm); transition: all var(--duration-fast);
}
.skill-list li:hover { background: var(--color-accent); color: #000; }

/* ── Showcase / Project Cards ── */
.showcase-card { padding: var(--space-8); border-left: 3px solid var(--color-accent); }
.project-content { display: flex; flex-direction: column; height: 100%; }
.project-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: var(--space-4); border-bottom: 1px dashed var(--color-border); padding-bottom: 8px; flex-wrap: wrap; gap: var(--space-2); }
.project-year { font-size: 0.75rem; color: var(--color-text-muted); }
.project-tag { font-size: 0.65rem; color: var(--color-accent); background: rgba(56, 189, 248, 0.1); padding: 2px 6px; border: 1px solid var(--color-accent); }
.project-title { font-size: 1.125rem; font-weight: 600; color: var(--color-text-primary); margin-bottom: 4px; }
.project-desc { font-size: 0.9375rem; color: var(--color-text-secondary); line-height: 1.6; }
.project-link { margin-top: auto; padding-top: var(--space-6); display: inline-flex; align-items: center; gap: var(--space-2); color: var(--color-accent); font-size: 0.8125rem; text-decoration: none;}
.project-link svg { transition: transform var(--duration-fast); }
.schematic-panel:hover .project-link svg { transform: translate(4px, -4px); }

/* ── Connect Grid ── */
.connect-grid { display: grid; grid-template-columns: 1fr; gap: var(--space-4); }
@media (min-width: 600px) { .connect-grid { grid-template-columns: repeat(2, 1fr); } }
.connect-link { flex-direction: row; justify-content: space-between; align-items: center; text-decoration: none; color: var(--color-text-primary); padding: var(--space-6); }
.connect-text { font-size: 0.8125rem; letter-spacing: 0.05em; }
.connect-arrow { color: var(--color-accent); transition: transform var(--duration-fast); }
.connect-link:hover .connect-arrow { transform: translate(4px, -4px); }

/* ── Footer ── */
.footer { border-top: 1px dashed var(--color-border); padding: var(--space-8) var(--space-6); margin-top: var(--space-16); text-align: center; max-width: var(--container-width); margin-left: auto; margin-right: auto; }
.footer-copy { font-size: 0.75rem; color: var(--color-text-muted); letter-spacing: 0.05em; }

/* ── Back to Top ── */
.back-to-top {
    position: fixed; bottom: 2rem; right: 2rem; padding: 0.75rem;
    background: rgba(56, 189, 248, 0.1); border: 1px solid var(--color-accent); color: var(--color-accent);
    border-radius: var(--radius-sm); cursor: pointer; z-index: 90;
    display: flex; align-items: center; justify-content: center;
    box-shadow: 0 0 10px rgba(56, 189, 248, 0.1);
    opacity: 0; pointer-events: none; transform: translateY(20px);
    transition: opacity var(--duration-base) var(--ease-out),
                transform var(--duration-base) var(--ease-out),
                background var(--duration-fast) var(--ease-out),
                color var(--duration-fast) var(--ease-out),
                box-shadow var(--duration-fast) var(--ease-out);
}
.back-to-top.is-visible { opacity: 1; pointer-events: auto; transform: translateY(0); }
.back-to-top:hover { background: var(--color-accent); color: #000; box-shadow: 0 0 15px var(--color-accent); transform: translateY(-3px); }

/* ── Scroll Reveal ── */
.js-reveal { opacity: 0; transform: translateY(12px); visibility: hidden; transition: opacity var(--duration-slow) var(--ease-out), transform var(--duration-slow) var(--ease-out); }
.js-reveal.is-visible { opacity: 1; transform: translateY(0); visibility: visible; }

/* ── Staggered Content Arrival Animations ── */
.hero.is-visible .hero-badge,
.hero.is-visible .hero-title,
.hero.is-visible .hero-bio,
.hero.is-visible .hero-actions,
.section.is-visible .bento-item,
.connect-section.is-visible .connect-link {
    animation: content-arrive 650ms var(--ease-out) both;
}

.hero.is-visible .hero-title { animation-delay: 100ms; }
.hero.is-visible .hero-bio { animation-delay: 200ms; }
.hero.is-visible .hero-actions { animation-delay: 300ms; }
.section.is-visible .bento-item:nth-child(2),
.connect-section.is-visible .connect-link:nth-child(2) { animation-delay: 90ms; }
.section.is-visible .bento-item:nth-child(3),
.connect-section.is-visible .connect-link:nth-child(3) { animation-delay: 180ms; }
.section.is-visible .bento-item:nth-child(4),
.connect-section.is-visible .connect-link:nth-child(4) { animation-delay: 270ms; }

@keyframes content-arrive {
    from { opacity: 0; translate: 0 16px; }
    to { opacity: 1; translate: 0 0; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    .js-reveal { opacity: 1; transform: none; visibility: visible; }
}

/* ── Project Gallery Images (shared by project pages) ── */
.project-gallery-img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    border: 1px dashed var(--color-border);
    margin-top: var(--space-4);
    transition: border-color var(--duration-base) ease,
                border-style var(--duration-base) ease,
                box-shadow var(--duration-base) ease;
}
.project-gallery-img:hover {
    border-style: solid;
    border-color: var(--color-accent);
    box-shadow: 0 0 15px rgba(56, 189, 248, 0.2);
}

/* ══════════════════════════════════════════
   RESPONSIVE: TABLET (481px – 768px)
   ══════════════════════════════════════════ */
@media (max-width: 768px) {
    .hero { margin-top: 18vh; }
    .hero-title { font-size: clamp(1.75rem, 5vw, 2.5rem); }
    .hero-bio { font-size: 1rem; }
    .navbar-wrapper { padding: 0 var(--space-4); }
}

/* ══════════════════════════════════════════
   RESPONSIVE: MOBILE (≤ 640px)
   ══════════════════════════════════════════ */
@media (max-width: 640px) {
    .logo-text { display: none; }
    .navbar-wrapper { top: var(--space-2); padding: 0 var(--space-3); }
    .navbar {
        flex-wrap: wrap;
        gap: var(--space-2);
        padding: var(--space-2) var(--space-3);
    }
    .nav-right { flex: 1 1 100%; gap: var(--space-2); }
    .nav-menu {
        flex: 1;
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: var(--space-1);
    }
    .nav-link {
        min-height: 36px;
        display: flex;
        align-items: center;
        justify-content: center;
        padding: var(--space-1) 2px;
        font-size: 0.65rem;
        text-align: center;
        white-space: normal;
    }
    .theme-toggle { width: 36px; height: 36px; }

    .hero { margin-top: 28vw; margin-bottom: var(--space-16); }
    .hero-title { font-size: clamp(1.5rem, 7vw, 2.2rem); }
    .hero-bio { font-size: 0.95rem; }

    .bento-grid { grid-template-columns: minmax(0, 1fr); }
    .schematic-panel { padding: var(--space-6); }
    
    .schematic-panel:hover { transform: none; }
    .schematic-panel:hover::before,
    .schematic-panel:hover::after { opacity: 0; }
    
    .back-to-top { bottom: 1rem; right: 1rem; }
    
    .footer { padding: var(--space-6) var(--space-4); }
}

/* ══════════════════════════════════════════
   RESPONSIVE: VERY SMALL (≤ 360px)
   ══════════════════════════════════════════ */
@media (max-width: 360px) {
    .main-container { padding: 0 var(--space-4); }
    .nav-link { font-size: 0.6rem; }
    .hero-actions { flex-direction: column; }
    .btn { width: 100%; text-align: center; }
    .connect-grid { grid-template-columns: 1fr; }
}

/* ══════════════════════════════════════════
   RESPONSIVE: LANDSCAPE PHONES
   ══════════════════════════════════════════ */
@media (max-height: 500px) and (orientation: landscape) {
    .hero { margin-top: 15vh; margin-bottom: var(--space-12); }
}
}