/* ============================================
   CONFIGURATION & CSS CUSTOM PROPERTIES
   ============================================ */
:root {
    --color-bg-primary: #07070b;
    --color-bg-secondary: #0d0c14;
    --color-bg-tertiary: #141226;
    --color-bg-elevated: #1a1733;
    --color-accent: #a78bfa;
    --color-accent-muted: rgba(167, 139, 250, 0.16);
    --color-text-primary: #f5f3ff;
    --color-text-secondary: rgba(245, 243, 255, 0.72);
    --color-text-muted: rgba(245, 243, 255, 0.48);
    --color-border: rgba(255, 255, 255, 0.10);
    --color-border-subtle: rgba(255, 255, 255, 0.06);
    --color-border-accent: rgba(167, 139, 250, 0.35);

    /* Typography */
    --font-display: 'Syne', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-body: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.9375rem;
    --font-size-base: 1.0625rem;
    --font-size-lg: 1.1875rem;
    --font-size-xl: 1.375rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 3rem;
    --font-size-5xl: 4rem;
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;

    /* Spacing */
    --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-20: 5rem;
    --space-24: 6rem;
    --space-32: 8rem;

    /* Animation */
    --duration-fast: 150ms;
    --duration-normal: 300ms;
    --ease-out: cubic-bezier(0.33, 1, 0.68, 1);

    /* Z-Index */
    --z-header: 100;

    /* Layout */
    --header-height: 72px;

    /* Shape & Elevation */
    --radius-sm: 10px;
    --radius-md: 14px;
    --radius-lg: 18px;
    --shadow-elevated: 0 18px 50px rgba(0, 0, 0, 0.45);
}

@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }

    html {
        scroll-behavior: auto;
    }
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    line-height: 1.75;
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    letter-spacing: 0.01em;
    position: relative;
    padding-top: var(--header-height);
}

::selection {
    background: var(--color-accent);
    color: var(--color-bg-primary);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

h1,
h2,
h3,
h4 {
    font-family: var(--font-display);
    font-weight: var(--font-weight-medium);
    line-height: 1.2;
    letter-spacing: -0.03em;
    overflow: visible;
}

/* ============================================
   LAYOUT
   ============================================ */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 var(--space-6);
}

@media (min-width: 1200px) {
    .container {
        padding: 0 var(--space-12);
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 var(--space-4);
    }
}

section {
    padding: var(--space-32) 0;
    scroll-margin-top: calc(var(--header-height) + var(--space-8));
}

@media (max-width: 768px) {
    section {
        padding: var(--space-20) 0;
    }
}

/* ============================================
   HEADER & NAVIGATION
   ============================================ */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-header);
    background: rgba(7, 7, 11, 0.72);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border-subtle);
}

.scroll-progress {
    position: absolute;
    left: 0;
    right: 0;
    top: 0;
    height: 2px;
    background: rgba(255, 255, 255, 0.03);
    overflow: hidden;
}

.scroll-progress__bar {
    height: 100%;
    width: 100%;
    transform: scaleX(0);
    transform-origin: left center;
    background: linear-gradient(90deg, var(--color-accent), rgba(34, 211, 238, 0.55));
    will-change: transform;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-4) 0;
    min-height: var(--header-height);
}

.logo {
    font-family: var(--font-display);
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-primary);
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: var(--space-8);
}

.nav-links a {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-normal);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    transition: color var(--duration-normal) var(--ease-out);
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--color-text-primary);
}

@media (max-width: 640px) {
    .nav-links {
        gap: var(--space-4);
    }

    .nav-links a {
        font-size: var(--font-size-xs);
    }
}

/* Skip Link */
.skip-to-main {
    position: absolute;
    top: -100px;
    left: var(--space-4);
    background: var(--color-text-primary);
    color: var(--color-bg-primary);
    padding: var(--space-2) var(--space-4);
    font-size: var(--font-size-sm);
    z-index: 1000;
}

.skip-to-main:focus {
    top: var(--space-4);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
    min-height: calc(100vh - var(--header-height));
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: var(--space-16);
    position: relative;
}

@media (max-width: 768px) {
    .hero {
        padding-top: var(--space-12);
    }
}

.hero-bg {
    position: absolute;
    inset: 0;
    overflow: hidden;
    pointer-events: none;
}

.constellation-canvas {
    position: absolute;
    inset: 0;
    opacity: 0;
    transition: opacity 0.5s ease;
}

.hero:hover .constellation-canvas {
    opacity: 1;
}

@media (hover: none) {
    .constellation-canvas {
        display: none;
    }
}

.hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--color-border-subtle);
}

@media (prefers-reduced-motion: reduce) {
    .aurora__layer {
        animation: none;
    }
}

.hero-content {
    text-align: center;
    max-width: 800px;
    position: relative;
    z-index: 1;
}

.hero-eyebrow {
    font-size: var(--font-size-xs);
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--color-text-muted);
    margin-bottom: var(--space-6);
}

.hero h1 {
    font-size: clamp(2.5rem, 10vw, var(--font-size-5xl));
    margin-bottom: var(--space-6);
    color: var(--color-text-primary);
}

.hero-tagline {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-12);
    max-width: 60ch;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.9;
    text-align: justify;
    hyphens: auto;
}

.hero-actions {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    margin-bottom: var(--space-16);
}

@media (max-width: 480px) {
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
}

.btn {
    padding: var(--space-3) var(--space-8);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-normal);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    transition: all var(--duration-normal) var(--ease-out);
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    border-radius: 9999px;
}

.btn-primary {
    background: var(--color-text-primary);
    color: var(--color-bg-primary);
}

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

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

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

.social-links {
    display: flex;
    gap: var(--space-6);
    justify-content: center;
}

.social-link {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-muted);
    transition: color var(--duration-normal) var(--ease-out);
}

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

.social-link:focus-visible {
    border-radius: 8px;
}

.social-link svg {
    width: 28px;
    height: 28px;
}

.social-link svg[class~="lucide"] {
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
}

.social-link svg:not([class]) {
    fill: currentColor;
    stroke: none;
}

/* ============================================
   SECTION HEADERS
   ============================================ */
.section-header {
    margin-bottom: var(--space-16);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

@media (max-width: 768px) {
    .section-header {
        margin-bottom: var(--space-12);
    }
}

.section-header h2 {
    font-size: var(--font-size-3xl);
    color: var(--color-text-primary);
    margin-bottom: var(--space-4);
}

.section-header .divider {
    width: 40px;
    height: 1px;
    background: var(--color-accent);
}

#about .section-header,
#experience .section-header {
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

/* ============================================
   ABOUT SECTION
   ============================================ */
.about-content {
    max-width: 700px;
    margin: 0 auto;
}

#projects .container,
#experience .container {
    max-width: 1140px;
}

.about-bio p {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    line-height: 1.9;
    margin-bottom: var(--space-8);
    text-align: justify;
    hyphens: auto;
}

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

.interests {
    margin-top: var(--space-8);
    padding-top: var(--space-8);
    border-top: 1px solid var(--color-border-subtle);
    text-align: center;
}

.interests-label {
    font-size: var(--font-size-xs);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-6);
}

.interests-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    justify-content: center;
}

.interest-tag {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    letter-spacing: 0.05em;
}

.interest-tag::before {
    content: '#';
    opacity: 0.5;
}

/* ============================================
   PROJECTS SECTION
   ============================================ */
.filter-container {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    margin-bottom: var(--space-12);
    justify-content: center;
}

.filter-btn {
    padding: var(--space-2) var(--space-4);
    font-size: var(--font-size-xs);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--color-text-muted);
    background: transparent;
    border: 1px solid transparent;
    transition: all var(--duration-normal) var(--ease-out);
    border-radius: 9999px;
}

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

.filter-btn.active {
    color: var(--color-text-primary);
    border-color: var(--color-border);
    background: rgba(255, 255, 255, 0.04);
    transform: translateY(-1px);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-6);
    justify-items: stretch;
    align-items: stretch;
}

@media (max-width: 400px) {
    .projects-grid {
        grid-template-columns: 1fr;
    }
}

.project-card {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border-subtle);
    padding: var(--space-8);
    display: flex;
    flex-direction: column;
    height: 100%;
    min-height: 360px;
    border-radius: var(--radius-lg);
    position: relative;
    overflow: visible;
    transition:
        border-color var(--duration-normal) var(--ease-out),
        transform var(--duration-normal) var(--ease-out),
        box-shadow var(--duration-normal) var(--ease-out);
}

.project-card::before {
    content: '';
    position: absolute;
    inset: -1px;
    background:
        radial-gradient(520px circle at 15% 0%, rgba(167, 139, 250, 0.20), transparent 55%),
        radial-gradient(520px circle at 85% 0%, rgba(34, 211, 238, 0.10), transparent 60%);
    opacity: 0.0;
    transition: opacity var(--duration-normal) var(--ease-out);
    pointer-events: none;
    border-radius: var(--radius-lg);
    z-index: 0;
}

.project-card:hover {
    border-color: var(--color-border-accent);
    box-shadow: var(--shadow-elevated);
    transform: translateY(-2px);
}

.project-card:hover::before {
    opacity: 1;
}

.project-card>* {
    position: relative;
    z-index: 1;
}

.project-number {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    margin-bottom: var(--space-4);
    font-family: var(--font-body);
    letter-spacing: 0.1em;
}

.project-title {
    font-family: var(--font-display);
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--space-3);
    color: var(--color-text-primary);
    letter-spacing: -0.02em;
}

.project-description {
    font-size: var(--font-size-base);
    color: var(--color-text-muted);
    margin-bottom: var(--space-6);
    flex-grow: 1;
    line-height: 1.7;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    margin-bottom: var(--space-6);
}

.tag {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    letter-spacing: 0.05em;
}

.tag::before {
    content: '#';
    opacity: 0.5;
}

.project-links {
    display: flex;
    gap: var(--space-4);
    padding-top: var(--space-6);
    border-top: 1px solid var(--color-border-subtle);
}

.project-link {
    font-size: var(--font-size-sm);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--color-text-muted);
    transition: color var(--duration-normal) var(--ease-out);
}

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

/* ============================================
   EXPERIENCE SECTION
   ============================================ */
.experience-timeline {
    max-width: 700px;
    margin: 0 auto;
}

.experience-item {
    padding-bottom: var(--space-12);
    margin-bottom: var(--space-12);
    border-bottom: 1px solid var(--color-border-subtle);
}

.experience-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.experience-header {
    margin-bottom: var(--space-4);
}

.experience-role {
    font-family: var(--font-display);
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-primary);
    margin-bottom: var(--space-1);
    letter-spacing: -0.02em;
}

.experience-meta {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    flex-wrap: wrap;
}

.experience-company {
    color: var(--color-text-secondary);
    font-size: var(--font-size-base);
}

.experience-divider {
    width: 1px;
    height: 12px;
    background: var(--color-border);
}

.experience-dates {
    font-size: var(--font-size-base);
    color: var(--color-text-muted);
}

.experience-highlights {
    list-style: none;
    margin-top: var(--space-6);
}

.experience-highlights li {
    padding: var(--space-2) 0;
    color: var(--color-text-muted);
    font-size: var(--font-size-base);
    padding-left: var(--space-6);
    position: relative;
    line-height: 1.7;
}

.experience-highlights li::before {
    content: '\2014';
    position: absolute;
    left: 0;
    color: var(--color-border);
}

/* ============================================
   FOOTER
   ============================================ */
footer {
    border-top: 1px solid var(--color-border-subtle);
    padding: var(--space-12) 0;
    margin-top: var(--space-16);
}

.footer-content {
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
}

.footer-text {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.back-to-top {
    position: fixed;
    bottom: var(--space-8);
    right: var(--space-8);
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-muted);
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border-subtle);
    border-radius: 12px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(8px);
    transition: opacity var(--duration-normal) var(--ease-out),
                visibility var(--duration-normal) var(--ease-out),
                transform var(--duration-normal) var(--ease-out),
                border-color var(--duration-normal) var(--ease-out),
                color var(--duration-normal) var(--ease-out),
                box-shadow var(--duration-normal) var(--ease-out);
    z-index: 90;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    border-color: var(--color-accent);
    color: var(--color-text-primary);
    box-shadow: 0 10px 30px rgba(167, 139, 250, 0.25);
}

@media (max-width: 480px) {
    section {
        padding: var(--space-16) 0;
    }
}

/* ============================================
   FOCUS STATES
   ============================================ */
:focus-visible {
    outline: 1px solid var(--color-accent);
    outline-offset: 2px;
}

@media (prefers-contrast: more) {
    :root {
        --color-text-secondary: rgba(245, 243, 255, 0.85);
        --color-text-muted: rgba(245, 243, 255, 0.65);
    }
}

/* ============================================
   SCROLL ANIMATIONS
   ============================================ */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

.fade-in-stagger>* {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease-out, transform 0.5s ease-out;
}

.fade-in-stagger.visible>*:nth-child(1) {
    transition-delay: 0.1s;
}

.fade-in-stagger.visible>*:nth-child(2) {
    transition-delay: 0.2s;
}

.fade-in-stagger.visible>*:nth-child(3) {
    transition-delay: 0.3s;
}

.fade-in-stagger.visible>*:nth-child(4) {
    transition-delay: 0.4s;
}

.fade-in-stagger.visible>*:nth-child(5) {
    transition-delay: 0.5s;
}

.fade-in-stagger.visible>*:nth-child(6) {
    transition-delay: 0.6s;
}

.fade-in-stagger.visible>* {
    opacity: 1;
    transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {

    .fade-in,
    .fade-in-stagger>* {
        opacity: 1 !important;
        transform: none !important;
        transition: none !important;
    }
}