:root {
    /* Dark Theme */
    --bg-color: #0d1117;
    --surface-color: #161b22;
    --surface-hover: #21262d;
    --text-main: #c9d1d9;
    --text-muted: #8b949e;
    --accent: #58a6ff;
    --accent-hover: #3182ce;
    --border: #30363d;
    --shadow: rgba(0, 0, 0, 0.4);
    
    /* Animation Timings */
    --transition-color: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-transform: 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

[data-theme="light"] {
    /* Light Theme */
    --bg-color: #f6f8fa;
    --surface-color: #ffffff;
    --surface-hover: #f3f4f6;
    --text-main: #24292f;
    --text-muted: #57606a;
    --accent: #0969da;
    --accent-hover: #0550ae;
    --border: #d0d7de;
    --shadow: rgba(0, 0, 0, 0.05);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--accent-hover);
}

/* navigation */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 5%;
    background-color: var(--surface-color);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo a {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links a {
    padding: 0.4rem 0.9rem;
    color: var(--text-main);
    font-weight: 500;
    font-size: 0.95rem;
    border-radius: 6px;
    border: 1px solid transparent;
    background-color: transparent;
    transition: all 0.2s ease;
}

.nav-links a:hover {
    color: var(--text-main);
    background-color: var(--surface-hover);
    border-color: var(--border);
}

.nav-controls {
    display: flex;
    align-items: center;
}

/* theme toggle button */
.theme-toggle {
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-main);
    cursor: pointer;
    padding: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-color);
}

.theme-toggle:hover {
    background-color: var(--surface-hover);
    border-color: var(--text-muted);
}

.theme-toggle svg {
    transition: transform var(--transition-transform);
}

/* spin and scale effect when class is toggled via JS */
.theme-toggle.animating svg {
    transform: rotate(180deg) scale(0.8);
}

/* hero Section */
.hero {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    padding: 8rem 5% 6rem;
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 0.5rem;
    line-height: 1.1;
    letter-spacing: -1px;
    position: relative;
    z-index: 2;
}

.age-badge {
    display: inline-flex;
    align-items: center;
    line-height: 1;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    background-color: var(--surface-hover);
    border: 1px solid var(--border);
    padding: 0.4rem 0.8rem 0.2rem;
    border-radius: 20px;
    margin-bottom: 1.5rem;
    font-family: ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
    letter-spacing: 0.5px;
    
    opacity: 0;
    transform: translateY(-20px);
    transition: opacity 0.3s ease, transform 0.3s ease;
    position: relative;
    z-index: 1;
    pointer-events: none;
}

.hero-content h1:hover + .age-badge,
.age-badge:hover {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 700px;
    margin-inline: auto;
}

/* Buttons */
.cta-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
}

.btn {
    display: inline-block;
    padding: 0.8rem 1.75rem;
    border-radius: 6px;
    font-weight: 600;
    transition: all 0.2s ease;
    text-align: center;
    min-width: 140px;
}

.btn.primary {
    background-color: var(--accent);
    color: #ffffff;
    border: 1px solid transparent;
}

.btn.primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--shadow);
}

.btn.secondary {
    background-color: var(--surface-color);
    border: 1px solid var(--border);
    color: var(--text-main);
}

.btn.secondary:hover {
    background-color: var(--surface-hover);
    border-color: var(--text-muted);
    transform: translateY(-1px);
}

/* Sections */
section {
    padding: 5rem 5%;
    border-top: 1px solid var(--border);
}

section h2 {
    font-size: 2.25rem;
    color: var(--text-main);
    margin-bottom: 3rem;
    text-align: center;
    font-weight: 700;
    letter-spacing: -0.5px;
}

/* About Section */
.about-content {
    max-width: 800px;
    margin: 0 auto;
    color: var(--text-muted);
    font-size: 1.15rem;
    line-height: 1.8;
}

.about-content p {
    margin-bottom: 1.5rem;
}

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

/* Projects Grid */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    max-width: 1100px;
    margin: 0 auto;
}

.project-card {
    background: var(--surface-color);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px var(--shadow);
    border-color: var(--text-muted);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.project-header h3 {
    font-size: 1.5rem;
    color: var(--text-main);
}

.badge {
    font-size: 0.75rem;
    padding: 0.25rem 0.6rem;
    border-radius: 12px;
    background-color: var(--surface-hover);
    border: 1px solid var(--border);
    color: var(--text-muted);
    font-weight: 600;
}

.project-card p {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.tech-stack {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
}

.tech-stack span {
    font-size: 0.8rem;
    font-family: ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
    color: var(--accent);
    background-color: rgba(88, 166, 255, 0.1);
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
}

[data-theme="light"] .tech-stack span {
    background-color: rgba(9, 105, 218, 0.1);
}

.project-links {
    display: flex;
    gap: 1.5rem;
    font-weight: 600;
    font-size: 0.95rem;
}

/* Contact Section */
.contact-section {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact-section p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 5%;
    border-top: 1px solid var(--border);
    background-color: var(--surface-color);
    color: var(--text-muted);
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .navbar {
        flex-wrap: wrap;
        padding: 1rem 5%;
        gap: 0.8rem 0;
    }

    .nav-links {
        order: 3;
        width: 100%;
        justify-content: center;
        flex-wrap: nowrap;
        gap: 0.2rem;
    }

    .nav-links a {
        padding: 0.3rem 0.4rem;
        font-size: 0.85rem;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }
}

/* transition API stuff for theme toggle */
::view-transition-old(root),
::view-transition-new(root) {
    animation: none;
    mix-blend-mode: normal;
}

::view-transition-old(root) {
    z-index: 1;
}

::view-transition-new(root) {
    z-index: 2;
}