/* ==========================================================================
   Design tokens
   ========================================================================== */
:root {
    --color-bg: #0b0f14;
    --color-bg-alt: #0f151c;
    --color-surface: #151c25;
    --color-surface-hover: #1b2430;
    --color-border: #263140;
    --color-text: #e8edf3;
    --color-text-muted: #9aacc0;
    --color-accent: #2dd4bf;
    --color-accent-hover: #5eead4;
    --color-accent-contrast: #04241f;

    --space-1: 0.5rem;
    --space-2: 1rem;
    --space-3: 1.5rem;
    --space-4: 2.5rem;
    --space-5: 4rem;

    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;

    --shadow-card: 0 8px 24px rgba(0, 0, 0, 0.35);
    --shadow-card-hover: 0 12px 32px rgba(0, 0, 0, 0.45);

    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --max-width: 1100px;
}

/* ==========================================================================
   Base
   ========================================================================== */
* {
    box-sizing: border-box;
}

body {
    font-family: var(--font-sans);
    margin: 0;
    padding: 0;
    color: var(--color-text);
    background: radial-gradient(circle at top, var(--color-bg-alt) 0%, var(--color-bg) 60%);
    line-height: 1.6;
}

h1, h2, h3 {
    color: var(--color-text);
    line-height: 1.25;
}

h2 {
    font-size: 1.75rem;
    margin-bottom: var(--space-2);
}

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

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

section {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--space-4) var(--space-2);
}

/* ==========================================================================
   Header / nav
   ========================================================================== */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: rgba(11, 15, 20, 0.9);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--color-border);
    margin: 0;
    padding: 0;
}

nav {
    max-width: var(--max-width);
    margin: 0 auto;
    overflow: hidden;
}

nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
}

nav ul li a {
    display: block;
    color: var(--color-text);
    text-align: center;
    padding: 16px 18px;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}

nav ul li a:hover,
nav ul li a.active {
    color: var(--color-accent);
}

/* ==========================================================================
   Hero / introduction
   ========================================================================== */
#introduction {
    text-align: center;
    padding-top: var(--space-5);
    padding-bottom: var(--space-5);
}

#introduction p {
    max-width: 720px;
    margin: var(--space-2) auto var(--space-3);
    color: var(--color-text-muted);
}

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

.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn:hover {
    transform: translateY(-2px);
}

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

.btn-primary:hover {
    color: var(--color-accent-contrast);
    box-shadow: var(--shadow-card-hover);
}

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

.btn-secondary:hover {
    color: var(--color-text);
    background-color: var(--color-surface-hover);
}

/* ==========================================================================
   Slideshow (Projects)
   ========================================================================== */
.slideshow-container {
    max-width: 1000px;
    position: relative;
    margin: auto;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-card);
}

.mySlides {
    display: none;
    transition: opacity 0.5s ease;
    width: 100%;
    aspect-ratio: 16 / 9;
}

.mySlides img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.prev, .next {
    font-size: 24px;
    color: white;
    background-color: rgba(0, 0, 0, 0.5);
    padding: 8px;
    border-radius: 50%;
    cursor: pointer;
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    user-select: none;
}

.prev:hover, .next:hover {
    background-color: rgba(0, 0, 0, 0.8);
    box-shadow: 0 0 8px rgba(255, 255, 255, 0.7);
}

.prev {
    left: 10px;
}

.next {
    right: 10px;
}

.numbertext {
    color: #f2f2f2;
    font-size: 12px;
    padding: 8px 12px;
    position: absolute;
    top: 0;
}

.text-box {
    text-align: center;
    padding: var(--space-2);
    background-color: var(--color-surface);
}

.slide-text {
    color: var(--color-text-muted);
    border: none;
    padding: 0;
    text-align: center;
    display: block;
    margin: 0 0 var(--space-1);
}

.project-button {
    background-color: var(--color-accent);
    border: none;
    color: var(--color-accent-contrast);
    padding: 10px 20px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 15px;
    font-weight: 600;
    border-radius: var(--radius-sm);
    margin: 4px;
    cursor: pointer;
    transition: transform 0.15s ease;
}

.project-button:hover {
    transform: translateY(-2px);
    color: var(--color-accent-contrast);
}

.dot {
    cursor: pointer;
    height: 10px;
    width: 10px;
    margin: 0 4px;
    background-color: var(--color-border);
    border-radius: 50%;
    display: inline-block;
    transition: background-color 0.3s ease;
}

.dot.active,
.dot:hover {
    background-color: var(--color-accent);
}

.video-container {
    width: 100%;
    position: relative;
    padding-top: 56.25%;
    overflow: hidden;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* ==========================================================================
   GitHub live projects
   ========================================================================== */
.repo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: var(--space-2);
    margin-top: var(--space-3);
}

.repo-card {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-2);
    box-shadow: var(--shadow-card);
    transition: transform 0.15s ease, box-shadow 0.15s ease;
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.repo-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-card-hover);
}

.repo-card h3 {
    margin: 0;
    font-size: 1.1rem;
}

.repo-card h3 a {
    color: var(--color-text);
    text-decoration: none;
}

.repo-card h3 a:hover {
    color: var(--color-accent);
}

.repo-card p {
    color: var(--color-text-muted);
    margin: 0;
    flex-grow: 1;
    font-size: 0.95rem;
}

.repo-meta {
    display: flex;
    gap: var(--space-2);
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

.repo-fallback {
    color: var(--color-text-muted);
    text-align: center;
}

#github-projects h3 {
    margin-top: var(--space-4);
    font-size: 1rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.github-activity {
    margin-top: var(--space-2);
    overflow-x: auto;
}

.github-activity a {
    display: inline-block;
    min-width: 100%;
}

.github-activity img {
    display: block;
    width: 100%;
    max-width: 100%;
    height: auto;
}

/* ==========================================================================
   About / Experience / Education
   ========================================================================== */
.experience-list {
    list-style: none;
    margin: var(--space-2) 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.experience-item {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-2);
}

.experience-item h4 {
    margin: 0 0 4px;
    color: var(--color-text);
}

.experience-item .experience-dates {
    color: var(--color-accent);
    font-size: 0.85rem;
    font-weight: 600;
    display: block;
    margin-bottom: var(--space-1);
}

.experience-item ul {
    margin: 0;
    padding-left: 1.2rem;
    color: var(--color-text-muted);
}

.experience-item li {
    margin-bottom: 4px;
}

/* ==========================================================================
   Skills marquee
   ========================================================================== */
#skills {
    padding: var(--space-2) 0;
    border-radius: var(--radius-md);
    position: relative;
}

.skills-categories {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.skills-category h3 {
    font-size: 1rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin: 0 0 var(--space-1);
}

.skills-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.icon-fallback {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--color-bg);
    padding: 0 4px;
    white-space: nowrap;
}

.icon-background {
    background-color: #fff;
    border-radius: var(--radius-sm);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px;
    position: relative;
}

.icon-background img {
    max-width: 60px;
    height: auto;
    display: block;
}

.icon-background:hover::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--color-surface);
    color: var(--color-text);
    padding: 5px 8px;
    border-radius: 5px;
    font-size: 12px;
    white-space: nowrap;
    z-index: 1;
}

.icon-background:hover::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.15);
    border-radius: var(--radius-sm);
}

/* ==========================================================================
   Certifications (compact chip grid)
   ========================================================================== */
.certifications-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: var(--space-1) 0 var(--space-3);
}

.cert-chip {
    position: relative;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 999px;
    padding: 6px 14px;
}

.cert-chip a {
    text-decoration: none;
}

.cert-chip-label {
    font-size: 0.85rem;
    color: var(--color-text);
}

.cert-chip a:hover .cert-chip-label {
    color: var(--color-accent);
}

.cert-chip:hover::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--color-surface-hover);
    color: var(--color-text);
    padding: 5px 8px;
    border-radius: 5px;
    font-size: 12px;
    white-space: nowrap;
    z-index: 1;
    margin-bottom: 6px;
    box-shadow: var(--shadow-card);
}

.cert-empty {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* ==========================================================================
   Contact
   ========================================================================== */
#contact form {
    max-width: 560px;
    margin: var(--space-2) auto 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

#contact label {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

#contact input,
#contact textarea {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 10px 12px;
    color: var(--color-text);
    font-family: inherit;
    font-size: 1rem;
}

#contact input:focus,
#contact textarea:focus {
    outline: none;
    border-color: var(--color-accent);
}

#contact textarea {
    min-height: 120px;
    resize: vertical;
}

#contact button {
    align-self: flex-start;
    background-color: var(--color-accent);
    color: var(--color-accent-contrast);
    border: none;
    padding: 12px 28px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: transform 0.15s ease;
}

#contact button:hover {
    transform: translateY(-2px);
}

#formStatus {
    margin-top: var(--space-1);
    font-size: 0.9rem;
}

#formStatus.success {
    color: var(--color-accent);
}

#formStatus.error {
    color: #f87171;
}

/* ==========================================================================
   Footer
   ========================================================================== */
footer {
    text-align: center;
    padding: var(--space-3) var(--space-2);
    color: var(--color-text-muted);
}

.social-media {
    display: flex;
    justify-content: center;
    gap: var(--space-1);
    margin-top: var(--space-2);
}

.social-media a,
.resume-download {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 10px;
    transition: background-color 0.2s ease, transform 0.15s ease;
}

.social-media a img,
.resume-download img {
    display: block;
    width: 26px;
    height: auto;
}

.social-media a:hover,
.resume-download:hover {
    background-color: var(--color-surface-hover);
    transform: translateY(-2px);
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media only screen and (max-width: 600px) {
    nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }

    section {
        padding: var(--space-3) var(--space-2);
    }

    body {
        font-size: 16px;
    }

    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }
}