/* ============================
   1. VARIABLES & RESET
   ============================ */
:root {
    --bg: #050505;
    --bg-elevated: #0a0a0a;
    --bg-hover: #0f0f0f;
    --fg: #ffffff;
    --grey: #888888;
    --grey-dim: #555555;
    --border: #222222;
    --alert: #ff3333;
    --acid: #ffeb3b;
    --acid-glow: rgba(255, 235, 59, 0.15);

    --font-head: 'Space Grotesk', sans-serif;
    --font-mono: 'Space Mono', monospace;

    --section-pad: clamp(60px, 10vw, 100px);
    --container-pad: clamp(16px, 4vw, 20px);
    --card-radius: 6px;
    --transition: 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    background-color: var(--bg);
    color: var(--fg);
    font-family: var(--font-mono);
    overflow-x: hidden;
    line-height: 1.7;
    font-size: clamp(14px, 1.6vw, 16px);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    /* Flex layout for recruiter-optimized section ordering */
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* ---- Recruiter-optimized section order ----
   Experience → Skills → Education → Projects → Publications → Activities */
header                  { order: 1; }
.hero                   { order: 2; }
.experience-section     { order: 3; }
.skills-section         { order: 4; }
.education-section      { order: 5; }
.work-section           { order: 6; }
.publications-section   { order: 7; }
.activities-section     { order: 8; }
footer                  { order: 9; }
.back-to-top            { order: 10; }

a { text-decoration: none; color: inherit; transition: var(--transition); }
ul { list-style: none; }
img { display: block; max-width: 100%; height: auto; }

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

/* ============================
   2. NAVBAR
   ============================ */
header {
    padding: 16px 0;
    border-bottom: 1px solid var(--border);
    background: rgba(5, 5, 5, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: var(--transition);
}
header.scrolled {
    padding: 10px 0;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
    border-bottom-color: transparent;
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: 700;
    font-size: 1.15rem;
    letter-spacing: -1px;
    color: var(--fg);
    z-index: 10;
    padding: 6px 12px;
    margin-left: -12px;
    border-radius: var(--card-radius);
    transition: var(--transition);
}
.logo:hover {
    background-color: var(--acid);
    color: var(--bg);
    box-shadow: 0 0 20px var(--acid-glow);
}

.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-links a {
    font-size: 0.8rem;
    color: var(--grey);
    padding: 8px 14px;
    border: 1px solid transparent;
    border-radius: var(--card-radius);
    transition: var(--transition);
    white-space: nowrap;
}
.nav-links a:not(.cta-alert):hover {
    color: var(--bg);
    background: var(--fg);
    border-color: var(--fg);
}
.nav-links a.cta-alert {
    border-color: var(--alert);
    color: var(--alert);
}
.nav-links a.cta-alert:hover {
    background-color: var(--alert);
    color: var(--fg);
    box-shadow: 0 0 12px rgba(255, 51, 51, 0.3);
}

/* Active nav highlight */
.nav-links a.active {
    color: var(--acid);
    border-color: rgba(255, 235, 59, 0.3);
}

/* Hamburger */
#nav-toggle { display: none; }
.hamburger { display: none; cursor: pointer; z-index: 110; padding: 8px; }
.hamburger-line {
    display: block;
    width: 22px;
    height: 2px;
    margin: 5px auto;
    background-color: var(--fg);
    transition: var(--transition);
    border-radius: 2px;
}

@media (max-width: 768px) {
    .hamburger { display: block; }
    .nav-links {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100dvh;
        background: rgba(5, 5, 5, 0.98);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 0;
        opacity: 0;
        visibility: hidden;
        transition: opacity 0.4s ease, visibility 0.4s ease;
    }
    .nav-links a {
        font-size: 1.2rem;
        padding: 20px 40px;
        width: auto;
        text-align: center;
        border-bottom: none;
        opacity: 0;
        transform: translateY(20px);
    }
    #nav-toggle:checked ~ .nav-links {
        opacity: 1;
        visibility: visible;
    }
    #nav-toggle:checked ~ .nav-links a {
        opacity: 1;
        transform: translateY(0);
    }
    #nav-toggle:checked ~ .nav-links a:nth-child(1) { transition: opacity 0.3s 0.1s, transform 0.3s 0.1s; }
    #nav-toggle:checked ~ .nav-links a:nth-child(2) { transition: opacity 0.3s 0.15s, transform 0.3s 0.15s; }
    #nav-toggle:checked ~ .nav-links a:nth-child(3) { transition: opacity 0.3s 0.2s, transform 0.3s 0.2s; }
    #nav-toggle:checked ~ .nav-links a:nth-child(4) { transition: opacity 0.3s 0.25s, transform 0.3s 0.25s; }
    #nav-toggle:checked ~ .nav-links a:nth-child(5) { transition: opacity 0.3s 0.3s, transform 0.3s 0.3s; }

    /* Burger X animation */
    #nav-toggle:checked ~ .hamburger .line-1 { transform: rotate(45deg) translate(5px, 5px); }
    #nav-toggle:checked ~ .hamburger .line-2 { opacity: 0; }
    #nav-toggle:checked ~ .hamburger .line-3 { transform: rotate(-45deg) translate(5px, -5px); }
}

/* ============================
   3. HERO
   ============================ */
.hero {
    padding: clamp(50px, 10vw, 80px) 0;
    border-bottom: 1px solid var(--border);
    min-height: clamp(60vh, 75vh, 85vh);
    display: flex;
    align-items: center;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: clamp(30px, 5vw, 60px);
    align-items: center;
    width: 100%;
}

.status-badge {
    display: inline-flex;
    align-items: center;
    font-size: 0.7rem;
    color: var(--acid);
    border: 1px solid rgba(255, 235, 59, 0.3);
    padding: 6px 14px;
    margin-bottom: 24px;
    text-transform: uppercase;
    letter-spacing: 2px;
    border-radius: 20px;
    background: var(--acid-glow);
}
.status-dot {
    display: inline-block;
    width: 7px;
    height: 7px;
    background: var(--acid);
    border-radius: 50%;
    margin-right: 10px;
    animation: blink 2s infinite;
    box-shadow: 0 0 6px var(--acid);
}

.greeting {
    font-family: var(--font-mono);
    font-size: clamp(1.2rem, 2.5vw, 1.6rem);
    color: var(--grey);
    margin-bottom: 16px;
    display: block;
    letter-spacing: -0.5px;
}
.greeting strong {
    color: var(--bg);
    background: var(--acid);
    padding: 2px 8px;
    font-weight: 700;
    border-radius: 3px;
}

h1 {
    font-family: var(--font-head);
    font-size: clamp(2.8rem, 6vw, 4.5rem);
    line-height: 0.95;
    font-weight: 500;
    letter-spacing: -2px;
    margin-bottom: 24px;
    text-transform: uppercase;
}

.hero-intro {
    color: var(--grey);
    font-size: clamp(0.9rem, 1.5vw, 1.05rem);
    max-width: 450px;
    line-height: 1.7;
    margin-bottom: 36px;
}

.btn-group { display: flex; gap: 16px; flex-wrap: wrap; }
.btn-hero {
    padding: 14px 28px;
    font-weight: 700;
    font-family: var(--font-head);
    text-transform: uppercase;
    letter-spacing: 1px;
    border: 1px solid var(--acid);
    border-radius: var(--card-radius);
    font-size: 0.85rem;
    transition: var(--transition);
    cursor: pointer;
}
.btn-primary { background: var(--acid); color: var(--bg); }
.btn-primary:hover {
    background: transparent;
    color: var(--acid);
    box-shadow: 0 0 20px var(--acid-glow);
}
.btn-secondary {
    border-color: var(--border);
    color: var(--fg);
    background: transparent;
}
.btn-secondary:hover {
    border-color: var(--fg);
    background: var(--fg);
    color: var(--bg);
}

/* Hero Image */
.hero-image-wrapper {
    position: relative;
    width: clamp(250px, 25vw, 350px);
    height: clamp(250px, 25vw, 350px);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
}
.hero-image-wrapper::before {
    content: "";
    position: absolute;
    inset: -15px;
    border-radius: 50%;
    border: 1px dashed var(--border);
    border-top-color: var(--acid);
    animation: spin 10s linear infinite;
}
.hero-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
    filter: grayscale(100%) contrast(1.1);
    transition: 0.5s ease;
    border: 2px solid var(--bg);
}
.hero-image-wrapper:hover .hero-img { filter: grayscale(0%) contrast(1); }

@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0; } }
@keyframes spin { 100% { transform: rotate(360deg); } }

/* ============================
   4. SECTION SHARED STYLES
   ============================ */
.section-header {
    margin-bottom: clamp(40px, 6vw, 60px);
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}
.section-title {
    font-family: var(--font-head);
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: -1px;
}
.section-counter {
    font-family: var(--font-mono);
    color: var(--acid);
    font-size: 0.8rem;
    border: 1px solid rgba(255, 235, 59, 0.3);
    padding: 5px 14px;
    border-radius: 20px;
    background: var(--acid-glow);
    white-space: nowrap;
}

/* ============================
   5. WORK / PROJECTS
   ============================ */
.work-section {
    padding: var(--section-pad) 0;
    border-bottom: 1px solid var(--border);
}

.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 380px), 1fr));
    gap: 24px;
}

.project-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-top: 3px solid var(--border);
    border-radius: var(--card-radius);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    height: 100%;
}
.project-card:hover {
    border-color: var(--acid);
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.5);
    background: var(--bg-hover);
}

.card-content {
    padding: clamp(24px, 4vw, 35px);
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.project-tech {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--acid);
    margin-bottom: 14px;
    display: block;
    letter-spacing: 0.5px;
}
.project-title {
    font-family: var(--font-head);
    font-size: clamp(1.3rem, 2.5vw, 1.8rem);
    margin-bottom: 12px;
    line-height: 1.15;
}
.project-desc {
    color: var(--grey);
    font-size: 0.9rem;
    line-height: 1.7;
    margin-bottom: 20px;
}

.tags-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: auto;
    padding-top: 18px;
    border-top: 1px solid var(--border);
}
.tech-tag {
    font-size: 0.7rem;
    background: rgba(255, 255, 255, 0.04);
    color: var(--grey);
    padding: 4px 10px;
    border: 1px solid var(--border);
    border-radius: 4px;
    transition: var(--transition);
}
.project-card:hover .tech-tag {
    border-color: rgba(255, 235, 59, 0.2);
    color: var(--fg);
}

/* ============================
   6. EXPERIENCE TIMELINE
   ============================ */
.experience-section {
    padding: var(--section-pad) 0;
    border-bottom: 1px solid var(--border);
    background-color: var(--bg-elevated);
}

.timeline {
    position: relative;
    padding-left: 36px;
}
.timeline::before {
    content: '';
    position: absolute;
    left: 7px;
    top: 0;
    bottom: 0;
    width: 1px;
    background: linear-gradient(to bottom, var(--acid), var(--border) 30%, var(--border) 70%, transparent);
}

.timeline-item {
    position: relative;
    margin-bottom: 40px;
    padding: clamp(20px, 3vw, 30px);
    background: var(--bg);
    border: 1px solid var(--border);
    border-left: 3px solid var(--acid);
    border-radius: 0 var(--card-radius) var(--card-radius) 0;
    transition: var(--transition);
}
.timeline-item:last-child { margin-bottom: 0; }
.timeline-item:hover {
    background: var(--bg-hover);
    transform: translateX(4px);
    box-shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
    border-color: rgba(255, 235, 59, 0.2);
    border-left-color: var(--acid);
}
.timeline-item::before {
    content: '';
    position: absolute;
    left: -42px;
    top: 30px;
    width: 11px;
    height: 11px;
    background: var(--acid);
    border-radius: 50%;
    border: 2px solid var(--bg);
    box-shadow: 0 0 8px var(--acid-glow);
}

.timeline-date {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--acid);
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
}
.timeline-badge {
    display: inline-block;
    font-size: 0.6rem;
    color: var(--bg);
    background: var(--grey);
    padding: 2px 8px;
    text-transform: uppercase;
    letter-spacing: 1px;
    border-radius: 3px;
    font-weight: 700;
}
.timeline-badge.on-site { background: var(--acid); }
.timeline-badge.remote { background: #4fc3f7; }
.timeline-badge.virtual { background: #ab47bc; color: var(--fg); }

.timeline-role {
    font-family: var(--font-head);
    font-size: clamp(1.1rem, 2vw, 1.35rem);
    font-weight: 500;
    margin-bottom: 4px;
    text-transform: uppercase;
    letter-spacing: -0.5px;
}
.timeline-company {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--grey);
    margin-bottom: 14px;
}
.timeline-desc {
    color: var(--grey);
    font-size: 0.85rem;
    line-height: 1.8;
}
.timeline-desc li {
    margin-bottom: 6px;
    padding-left: 16px;
    position: relative;
    list-style: none;
}
.timeline-desc li::before {
    content: ">";
    position: absolute;
    left: 0;
    color: var(--acid);
    font-family: var(--font-mono);
    font-size: 0.8rem;
}

/* ============================
   7. PUBLICATIONS
   ============================ */
.publications-section {
    padding: var(--section-pad) 0;
    border-bottom: 1px solid var(--border);
}

.pub-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 300px), 1fr));
    gap: 24px;
}
.pub-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    padding: clamp(24px, 3vw, 30px);
    border-radius: var(--card-radius);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}
.pub-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: linear-gradient(90deg, var(--acid), transparent);
    opacity: 0.6;
    transition: opacity var(--transition);
}
.pub-card:hover::before { opacity: 1; }
.pub-card:hover {
    border-color: var(--acid);
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
}
.pub-venue {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--acid);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 12px;
    display: block;
}
.pub-title {
    font-family: var(--font-head);
    font-size: clamp(1rem, 1.8vw, 1.2rem);
    font-weight: 500;
    margin-bottom: 12px;
    line-height: 1.35;
}
.pub-doi {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--grey-dim);
    word-break: break-all;
    line-height: 1.6;
}
.pub-doi a {
    color: var(--acid);
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}
.pub-doi a:hover { border-bottom-color: var(--acid); }

/* ============================
   8. ACTIVITIES
   ============================ */
.activities-section {
    padding: var(--section-pad) 0;
    border-bottom: 1px solid var(--border);
    background-color: var(--bg-elevated);
}

.activities-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
    gap: 24px;
}
.activity-card {
    background: var(--bg);
    border: 1px solid var(--border);
    padding: clamp(24px, 3vw, 30px);
    border-radius: var(--card-radius);
    transition: var(--transition);
}
.activity-card:hover {
    border-color: var(--fg);
    transform: translateY(-3px);
    background: var(--bg-hover);
    box-shadow: 0 8px 28px rgba(0, 0, 0, 0.35);
}
.activity-date {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--acid);
    margin-bottom: 10px;
    display: block;
}
.activity-role {
    font-family: var(--font-head);
    font-size: 1.05rem;
    font-weight: 500;
    margin-bottom: 4px;
    text-transform: uppercase;
}
.activity-org {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--grey);
    margin-bottom: 12px;
}
.activity-desc {
    color: var(--grey);
    font-size: 0.82rem;
    line-height: 1.65;
}

/* ============================
   9. EDUCATION
   ============================ */
.education-section {
    padding: var(--section-pad) 0;
    border-bottom: 1px solid var(--border);
}
.edu-table-wrapper {
    overflow-x: auto;
    border-radius: var(--card-radius);
    -webkit-overflow-scrolling: touch;
}
.edu-table {
    width: 100%;
    border-collapse: collapse;
    border: 1px solid var(--border);
    border-radius: var(--card-radius);
}
.edu-table thead th {
    font-family: var(--font-head);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--acid);
    background: rgba(255, 235, 59, 0.04);
    padding: 16px 20px;
    text-align: left;
    border-bottom: 2px solid rgba(255, 235, 59, 0.3);
    white-space: nowrap;
}
.edu-table tbody tr {
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}
.edu-table tbody tr:last-child { border-bottom: none; }
.edu-table tbody tr:hover { background: var(--bg-hover); }
.edu-table tbody td {
    padding: 18px 20px;
    font-size: 0.88rem;
    vertical-align: middle;
}
.edu-table .edu-degree {
    font-family: var(--font-head);
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--fg);
}
.edu-table .edu-inst {
    color: var(--grey);
    font-size: 0.82rem;
}
.edu-table .edu-year {
    font-family: var(--font-mono);
    color: var(--fg);
    font-size: 0.9rem;
    font-weight: 700;
    white-space: nowrap;
}
.edu-table .edu-year strong {
    color: var(--acid);
    font-size: 0.95rem;
}
.edu-table .edu-result {
    font-family: var(--font-mono);
    color: var(--acid);
    font-weight: 700;
    font-size: 0.95rem;
    white-space: nowrap;
}

/* Mobile education cards */
.edu-cards { display: none; }
.edu-card-item {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-left: 3px solid var(--acid);
    border-radius: 0 var(--card-radius) var(--card-radius) 0;
    padding: 24px;
    margin-bottom: 16px;
    transition: var(--transition);
}
.edu-card-item:last-child { margin-bottom: 0; }
.edu-card-item:hover {
    background: var(--bg-hover);
    border-color: rgba(255, 235, 59, 0.2);
    border-left-color: var(--acid);
}
.edu-card-item .edu-card-year {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--acid);
    margin-bottom: 6px;
    display: block;
    font-weight: 700;
}
.edu-card-item .edu-card-degree {
    font-family: var(--font-head);
    font-size: 1.05rem;
    font-weight: 500;
    margin-bottom: 4px;
}
.edu-card-item .edu-card-inst {
    font-size: 0.8rem;
    color: var(--grey);
    margin-bottom: 10px;
}
.edu-card-item .edu-card-result {
    font-family: var(--font-mono);
    color: var(--acid);
    font-weight: 700;
    font-size: 1rem;
}

/* ============================
   10. SKILLS
   ============================ */
.skills-section {
    padding: var(--section-pad) 0;
    border-bottom: 1px solid var(--border);
    background-color: var(--bg-elevated);
}
.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    background: var(--border);
    border: 1px solid var(--border);
    border-radius: var(--card-radius);
    overflow: hidden;
}
.skill-card {
    background: var(--bg);
    padding: clamp(28px, 4vw, 40px);
    height: 100%;
    transition: var(--transition);
}
.skill-card:hover { background: var(--bg-hover); }

.skill-icon {
    font-size: 1.8rem;
    color: var(--grey-dim);
    margin-bottom: 18px;
    font-family: var(--font-mono);
    transition: color var(--transition);
}
.skill-card:hover .skill-icon { color: var(--acid); }
.skill-title {
    font-family: var(--font-head);
    font-size: clamp(1.2rem, 2vw, 1.5rem);
    margin-bottom: 18px;
    text-transform: uppercase;
}

.skill-list li {
    margin-bottom: 10px;
    padding-left: 16px;
    position: relative;
    color: var(--grey);
    font-size: 0.85rem;
}
.skill-list li::before {
    content: "+";
    position: absolute;
    left: 0;
    color: var(--acid);
}

/* ============================
   11. FOOTER
   ============================ */
footer {
    padding: var(--section-pad) 0;
    text-align: center;
}
.contact-cta { max-width: 550px; margin: 0 auto 50px auto; }
.contact-head {
    font-family: var(--font-head);
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    line-height: 1;
    margin-bottom: 20px;
    text-transform: uppercase;
}
.contact-sub {
    color: var(--grey);
    margin-bottom: 36px;
    font-size: clamp(0.9rem, 1.5vw, 1.05rem);
    line-height: 1.7;
}

.email-link {
    font-family: var(--font-mono);
    font-size: clamp(1rem, 2vw, 1.4rem);
    color: var(--fg);
    border-bottom: 2px solid var(--acid);
    padding-bottom: 4px;
    transition: var(--transition);
}
.email-link:hover {
    background: var(--acid);
    color: var(--bg);
    padding: 4px 8px;
    border-radius: 3px;
}

.footer-bottom {
    margin-top: clamp(40px, 6vw, 80px);
    padding-top: 20px;
    border-top: 1px solid var(--border);
    color: #444;
    font-size: 0.75rem;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 8px;
}

/* ============================
   12. SCROLL ANIMATIONS
   ============================ */
.fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94),
                transform 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Staggered children animation */
.fade-in.visible .project-card,
.fade-in.visible .timeline-item,
.fade-in.visible .pub-card,
.fade-in.visible .activity-card,
.fade-in.visible .skill-card,
.fade-in.visible .edu-card-item {
    animation: fadeSlideUp 0.5s ease-out both;
}
.fade-in.visible :is(.project-card, .timeline-item, .pub-card, .activity-card, .skill-card, .edu-card-item):nth-child(1) { animation-delay: 0.05s; }
.fade-in.visible :is(.project-card, .timeline-item, .pub-card, .activity-card, .skill-card, .edu-card-item):nth-child(2) { animation-delay: 0.12s; }
.fade-in.visible :is(.project-card, .timeline-item, .pub-card, .activity-card, .skill-card, .edu-card-item):nth-child(3) { animation-delay: 0.19s; }
.fade-in.visible :is(.project-card, .timeline-item):nth-child(n+4) { animation-delay: 0.26s; }

@keyframes fadeSlideUp {
    from { opacity: 0; transform: translateY(16px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* Back to top */
.back-to-top {
    position: fixed;
    bottom: 28px;
    right: 28px;
    width: 44px;
    height: 44px;
    background: var(--acid);
    color: var(--bg);
    border: none;
    cursor: pointer;
    font-size: 1.1rem;
    font-family: var(--font-mono);
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--card-radius);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 99;
}
.back-to-top.show { opacity: 1; visibility: visible; }
.back-to-top:hover {
    box-shadow: 0 0 20px var(--acid-glow);
    transform: translateY(-3px);
}

/* ============================
   13. RESPONSIVE
   ============================ */

/* Tablet */
@media (max-width: 900px) {
    .hero-grid {
        display: flex;
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 30px;
    }
    .hero-image-wrapper { display: none; }
    .hero-text {
        display: flex;
        flex-direction: column;
        align-items: center;
        width: 100%;
    }
    .hero-intro { margin: 0 auto 36px auto; text-align: center; }
    .btn-group { justify-content: center; }

    .skills-grid { grid-template-columns: 1fr; }
    .footer-bottom { flex-direction: column; align-items: center; gap: 8px; }
}

/* Mobile */
@media (max-width: 768px) {
    .project-grid { grid-template-columns: 1fr; }
    .pub-grid { grid-template-columns: 1fr; }
    .activities-grid { grid-template-columns: 1fr; }

    .timeline { padding-left: 28px; }
    .timeline-item::before { left: -34px; width: 9px; height: 9px; }

    /* Switch education table to cards on mobile */
    .edu-table-wrapper { display: none; }
    .edu-cards { display: block; }
}

/* Small mobile */
@media (max-width: 480px) {
    .hero { min-height: auto; padding: 40px 0; }
    .btn-group { flex-direction: column; width: 100%; gap: 12px; }
    .btn-hero { width: 100%; text-align: center; padding: 14px 20px; }
    .back-to-top { bottom: 16px; right: 16px; width: 40px; height: 40px; font-size: 1rem; }

    .section-header { flex-direction: column; gap: 10px; }
    .section-counter { align-self: flex-start; }

    .timeline { padding-left: 22px; }
    .timeline::before { left: 5px; }
    .timeline-item { padding: 18px; }
    .timeline-item::before { left: -28px; width: 8px; height: 8px; top: 24px; }
    .timeline-desc li { font-size: 0.8rem; }
}

/* Ultra-small */
@media (max-width: 360px) {
    h1 { font-size: 2.2rem; letter-spacing: -1px; }
    .greeting { font-size: 1.1rem; }
    .status-badge { font-size: 0.6rem; letter-spacing: 1px; }
}