/* =========================================================
   Kim Ngan Le Huynh - Personal Portfolio & Technical Journal
   Design System: Midnight Slate, Neon Cyan & Violet Accents
   ========================================================= */

:root {
    --bg-main: #0b0f19;
    --bg-card: #151c2c;
    --bg-card-hover: #1e293b;
    --border-color: rgba(255, 255, 255, 0.08);
    --border-highlight: rgba(6, 182, 212, 0.4);
    
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --text-dim: #64748b;
    
    --accent-cyan: #06b6d4;
    --accent-violet: #8b5cf6;
    --accent-gold: #f59e0b;
    --accent-gradient: linear-gradient(135deg, #06b6d4 0%, #8b5cf6 100%);
    --card-glow: 0 10px 30px -10px rgba(6, 182, 212, 0.15);

    --font-heading: 'Space Grotesk', sans-serif;
    --font-body: 'Plus Jakarta Sans', sans-serif;
    --font-code: 'Fira Code', monospace;
}

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

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

body {
    background-color: var(--bg-main);
    color: var(--text-main);
    font-family: var(--font-body);
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* NAVBAR */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(11, 15, 25, 0.85);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 76px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.nav-brand {
    font-family: var(--font-heading);
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--text-main);
    text-decoration: none;
    display: flex;
    align-items: center;
}

.brand-dot {
    color: var(--accent-cyan);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-link {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s ease;
}

.nav-link:hover {
    color: var(--accent-cyan);
}

.btn-contact {
    padding: 8px 18px;
    background: rgba(6, 182, 212, 0.1);
    border: 1px solid var(--border-highlight);
    border-radius: 50px;
    color: var(--accent-cyan);
}

.btn-contact:hover {
    background: var(--accent-cyan);
    color: #000;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
}

.nav-toggle .bar {
    display: block;
    width: 24px;
    height: 2px;
    margin: 5px 0;
    background-color: var(--text-main);
    transition: 0.3s;
}

/* BUTTONS */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.95rem;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.25s ease;
}

.btn-primary {
    background: var(--accent-gradient);
    color: #fff;
    box-shadow: 0 4px 20px rgba(6, 182, 212, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(6, 182, 212, 0.45);
}

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

.btn-secondary:hover {
    border-color: var(--accent-violet);
    color: var(--accent-violet);
}

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

.btn-outline:hover {
    border-color: var(--accent-cyan);
    color: var(--accent-cyan);
}

.btn-text {
    color: var(--text-muted);
}

.btn-text:hover {
    color: var(--text-main);
}

/* HERO SECTION */
.hero-section {
    position: relative;
    padding: 160px 0 100px;
    overflow: hidden;
}

.hero-bg-glow {
    position: absolute;
    top: -150px;
    left: 50%;
    transform: translateX(-50%);
    width: 700px;
    height: 700px;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.12) 0%, rgba(139, 92, 246, 0.06) 50%, transparent 70%);
    pointer-events: none;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: rgba(6, 182, 212, 0.08);
    border: 1px solid rgba(6, 182, 212, 0.25);
    border-radius: 50px;
    font-size: 0.85rem;
    color: var(--accent-cyan);
    margin-bottom: 24px;
}

.pulse-dot {
    width: 8px;
    height: 8px;
    background-color: var(--accent-cyan);
    border-radius: 50%;
    box-shadow: 0 0 10px var(--accent-cyan);
}

.hero-title {
    font-family: var(--font-heading);
    font-size: 3.8rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 16px;
    background: linear-gradient(180deg, #ffffff 0%, #cbd5e1 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--accent-cyan);
    margin-bottom: 20px;
}

.hero-subtitle .divider {
    color: var(--text-dim);
    margin: 0 6px;
}

.hero-tagline {
    font-size: 1.35rem;
    font-weight: 500;
    color: var(--text-main);
    margin-bottom: 20px;
    max-width: 800px;
    border-left: 3px solid var(--accent-violet);
    padding-left: 16px;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 750px;
    margin-bottom: 36px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 16px;
    margin-bottom: 60px;
}

/* PROOF BAR */
.proof-bar {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    padding: 24px;
    background: rgba(21, 28, 44, 0.6);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    backdrop-filter: blur(10px);
}

.proof-item {
    display: flex;
    flex-direction: column;
}

.proof-num {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-cyan);
}

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

/* SECTIONS GLOBAL */
.section {
    padding: 100px 0;
    border-top: 1px solid var(--border-color);
}

.section-header {
    margin-bottom: 50px;
}

.section-tag {
    font-family: var(--font-code);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-cyan);
    letter-spacing: 1.5px;
    display: block;
    margin-bottom: 10px;
}

.section-title {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 700px;
}

/* ABOUT SECTION */
.about-grid {
    display: grid;
    grid-template-columns: 1.4fr 1fr;
    gap: 40px;
    margin-bottom: 60px;
}

.lead-text {
    font-size: 1.15rem;
    line-height: 1.7;
    margin-bottom: 20px;
}

.about-bio p {
    color: var(--text-muted);
    margin-bottom: 16px;
}

.pipeline-pill {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    padding: 14px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    margin: 24px 0 10px;

}

.pill-step {
    font-family: var(--font-code);
    font-size: 0.85rem;
    color: var(--accent-cyan);
    font-weight: 600;
}

.pill-arrow {
    color: var(--text-dim);

}

.caption-text {
    font-size: 0.85rem;
    color: var(--text-dim);

}

.about-interests-box {
    padding: 30px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
}

.about-interests-box h3 {
    font-size: 1.15rem;
    margin-bottom: 16px;
    color: var(--text-main);
}

.tags-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag {
    padding: 6px 12px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.mt-4 { margin-top: 24px; }
.mt-5 { margin-top: 48px; }

.exploring-list {
    list-style: none;
}

.exploring-list li {
    font-size: 0.92rem;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.exploring-list .bullet {
    color: var(--accent-violet);
    margin-right: 6px;
}

/* HOW I THINK */
.think-section {
    margin-top: 60px;
}

.think-title {
    font-size: 1.5rem;
    margin-bottom: 24px;
}

.think-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
}

.think-card {
    padding: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    transition: transform 0.25s ease, border-color 0.25s ease;
}

.think-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent-cyan);
}

.think-icon {
    font-size: 2rem;
    margin-bottom: 12px;
}

.think-card h4 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: var(--text-main);
}

.think-card p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* PROJECTS CASE STUDIES */
.project-case-study {
    padding: 36px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    transition: border-color 0.3s ease;
}

.project-case-study:hover {
    border-color: var(--border-highlight);
    box-shadow: var(--card-glow);
}

.project-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}

.project-category {
    font-family: var(--font-code);
    font-size: 0.8rem;
    color: var(--accent-cyan);
    text-transform: uppercase;
}

.project-domain {
    font-family: var(--font-code);
    font-size: 0.8rem;
    color: var(--text-dim);
}

.project-title {
    font-family: var(--font-heading);
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.project-subtitle {
    font-size: 1.1rem;
    color: var(--accent-violet);
    margin-bottom: 16px;
}

.project-desc {
    font-size: 1.05rem;
    color: var(--text-muted);
    margin-bottom: 24px;
    max-width: 900px;
}

/* PIPELINE VISUALIZER */
.pipeline-visualizer {
    padding: 20px 24px;
    background: rgba(11, 15, 25, 0.7);
    border: 1px solid var(--border-color);
    border-radius: 14px;
    margin-bottom: 28px;
}

.pipeline-title {
    font-family: var(--font-code);
    font-size: 0.85rem;
    color: var(--text-dim);
    margin-bottom: 14px;
    text-transform: uppercase;
}

.pipeline-flow {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px;
}

.flow-step {
    display: flex;
    flex-direction: column;
    padding: 10px 16px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    min-width: 110px;
}

.flow-step.highlight {
    border-color: var(--accent-cyan);
    background: rgba(6, 182, 212, 0.1);
}

.step-num {
    font-family: var(--font-code);
    font-size: 0.75rem;
    color: var(--text-dim);
}

.step-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-main);
}

.step-detail {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.flow-arrow {
    color: var(--accent-cyan);
    font-weight: bold;
}

.case-study-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 30px;
}

.built-column h4, .tech-column h4 {
    font-size: 1.05rem;
    margin-bottom: 14px;
    color: var(--text-main);
}

.built-column ul {
    list-style: none;
}

.built-column li {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 10px;
    position: relative;
    padding-left: 20px;
}

.built-column li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--accent-cyan);
    font-weight: bold;
}

.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tech-tag {
    font-family: var(--font-code);
    font-size: 0.8rem;
    padding: 6px 12px;
    background: rgba(139, 92, 246, 0.1);
    border: 1px solid rgba(139, 92, 246, 0.25);
    border-radius: 6px;
    color: var(--accent-violet);
}

/* EXPERIMENTS */
.experiments-title {
    font-size: 1.6rem;
    margin-bottom: 8px;
}

.experiments-subtitle {
    color: var(--text-muted);
    margin-bottom: 24px;
}

.experiments-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
}

.exp-card {
    padding: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 14px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: transform 0.25s ease;
}

.exp-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent-cyan);
}

.exp-num {
    font-family: var(--font-code);
    font-size: 0.85rem;
    color: var(--accent-cyan);
    margin-bottom: 8px;
}

.exp-card h4 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: var(--text-main);
}

.exp-card p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.exp-tag {
    font-family: var(--font-code);
    font-size: 0.75rem;
    color: var(--accent-violet);
    align-self: flex-start;
}

/* WRITING SECTION */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.article-card {
    padding: 28px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    cursor: pointer;
    transition: transform 0.25s ease, border-color 0.25s ease;
    display: flex;
    flex-direction: column;
}

.article-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent-cyan);
}

.article-meta {
    display: flex;
    justify-content: space-between;
    font-family: var(--font-code);
    font-size: 0.8rem;
    color: var(--text-dim);
    margin-bottom: 12px;
}

.article-cat {
    color: var(--accent-cyan);
}

.article-title {
    font-size: 1.2rem;
    margin-bottom: 12px;
    color: var(--text-main);
    line-height: 1.4;
}

.article-excerpt {
    font-size: 0.92rem;
    color: var(--text-muted);
    margin-bottom: 20px;
    flex-grow: 1;
}

.article-link {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-cyan);
}

/* WORK TIMELINE */
.timeline {
    position: relative;
    padding-left: 20px;
    border-left: 2px solid var(--border-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 40px;
}

.timeline-item::before {
    content: "";
    position: absolute;
    left: -27px;
    top: 4px;
    width: 12px;
    height: 12px;
    background: var(--accent-cyan);
    border-radius: 50%;
    box-shadow: 0 0 10px var(--accent-cyan);
}

.timeline-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
    margin-bottom: 6px;
}

.timeline-period {
    font-family: var(--font-code);
    font-size: 0.85rem;
    color: var(--accent-cyan);
}

.timeline-role {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text-main);
}

.timeline-org {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 10px;
}

.timeline-bullets {
    list-style: none;
}

.timeline-bullets li {
    font-size: 0.92rem;
    color: var(--text-muted);
    margin-bottom: 6px;
    padding-left: 16px;
    position: relative;
}

.timeline-bullets li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--accent-violet);
}

/* CV CARD */
.cv-card {
    padding: 36px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 20px;
}

.cv-header-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 28px;
}

.cv-name {
    font-family: var(--font-heading);
    font-size: 1.8rem;
}

.cv-title-sub {
    color: var(--accent-cyan);
    font-size: 1rem;
}

.cv-skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 24px;
}

.cv-skill-group h4 {
    font-size: 1.05rem;
    margin-bottom: 8px;
}

.cv-skill-group p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* CONTACT SECTION */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 40px;
}

.info-item {
    margin-bottom: 24px;
}

.info-label {
    font-family: var(--font-code);
    font-size: 0.8rem;
    color: var(--text-dim);
    display: block;
    margin-bottom: 4px;
}

.info-value, .info-links a {
    font-size: 1.1rem;
    color: var(--text-main);
    text-decoration: none;
}

.info-links a:hover, .info-value:hover {
    color: var(--accent-cyan);
}

.contact-form {
    padding: 32px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 12px 16px;
    background: rgba(11, 15, 25, 0.7);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-main);
    font-family: var(--font-body);
    font-size: 0.95rem;
    transition: border-color 0.2s ease;
}

.form-group input:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--accent-cyan);
}

.btn-block {
    width: 100%;
    justify-content: center;
}

.form-feedback {
    margin-top: 14px;
    font-size: 0.9rem;
    text-align: center;
}

/* FOOTER */
.footer {
    padding: 60px 0 30px;
    border-top: 1px solid var(--border-color);
    background: rgba(11, 15, 25, 0.95);
}

.footer-container {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 30px;
    margin-bottom: 40px;
}

.footer-brand h3 {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    margin-bottom: 4px;
}

.footer-brand p {
    color: var(--accent-cyan);
    font-size: 0.9rem;
}

.tagline-sm {
    color: var(--text-muted) !important;
    font-size: 0.85rem !important;
    margin-top: 6px;
}

.footer-links {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: var(--accent-cyan);
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--text-dim);
}

/* MODAL */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(11, 15, 25, 0.85);
    backdrop-filter: blur(10px);
}

.modal-content {
    position: relative;
    background: var(--bg-card);
    margin: 60px auto;
    padding: 40px;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    max-width: 800px;
    max-height: 80vh;
    overflow-y: auto;
}

.modal-close {
    position: absolute;
    right: 24px;
    top: 20px;
    font-size: 1.8rem;
    color: var(--text-muted);
    cursor: pointer;
}

.modal-close:hover {
    color: var(--accent-cyan);
}

/* RESPONSIVE */
@media (max-width: 900px) {
    .hero-title { font-size: 2.8rem; }
    .about-grid, .case-study-grid, .contact-grid { grid-template-columns: 1fr; }
    .nav-menu {
        display: none;
        position: absolute;
        top: 76px;
        left: 0;
        width: 100%;
        background: var(--bg-main);
        flex-direction: column;
        padding: 24px;
        border-bottom: 1px solid var(--border-color);
    }
    .nav-menu.active { display: flex; }
    .nav-toggle { display: block; }
}