/* ==========================================================================
   Portfolio Joaquín Molinos — Estilos principales
   Estética neumorphism/claymorphism inspirada en joacomoli.netlify.app
   ========================================================================== */

:root {
    --bg: #f0f0f0;
    --bg-card: #f0f0f0;
    --text: #4d4d4d;
    --text-muted: #7a7a7a;
    --text-dark: #2a2a2a;
    --accent-start: #0123b8;
    --accent-end: #46f2fc;
    --accent: #0a58ca;
    --gold: #d4a017;
    --shadow-dark: #d1d1d1;
    --shadow-light: #ffffff;
    --radius: 16px;
    --radius-sm: 10px;
    --radius-lg: 24px;
    --font-main: 'Montserrat', system-ui, sans-serif;
    --font-display: 'Satisfy', cursive;
    --header-h: 72px;
    --container: 1140px;
    --transition: 0.25s ease;
    --neu-shadow: 8px 8px 20px var(--shadow-dark), -8px -8px 20px var(--shadow-light);
    --neu-shadow-sm: 4px 4px 12px var(--shadow-dark), -4px -4px 12px var(--shadow-light);
    --neu-inset: inset 4px 4px 10px var(--shadow-dark), inset -4px -4px 10px var(--shadow-light);
}

[data-theme="dark"] {
    --bg: #16161a;
    --bg-card: #1e1e24;
    --text: #c8c8d0;
    --text-muted: #9494a0;
    --text-dark: #f0f0f5;
    --accent-start: #3d7bff;
    --accent-end: #46f2fc;
    --accent: #6ea8fe;
    --gold: #e8c547;
    --shadow-dark: #0a0a0c;
    --shadow-light: #2a2a32;
    --neu-shadow: 8px 8px 20px var(--shadow-dark), -8px -8px 20px var(--shadow-light);
    --neu-shadow-sm: 4px 4px 12px var(--shadow-dark), -4px -4px 12px var(--shadow-light);
    --neu-inset: inset 4px 4px 10px var(--shadow-dark), inset -4px -4px 10px var(--shadow-light);
}

[data-theme="dark"] .site-header {
    background: rgba(22, 22, 26, 0.9);
    border-bottom-color: rgba(42, 42, 50, 0.6);
}

[data-theme="dark"] .nav-menu {
    background: rgba(22, 22, 26, 0.97);
}

[data-theme="dark"] .clay-card {
    border-color: rgba(255, 255, 255, 0.05);
}

[data-theme="dark"] .hero-badge {
    background: rgba(30, 30, 36, 0.92);
    color: var(--text-dark);
}

[data-theme="dark"] .form-group input,
[data-theme="dark"] .form-group select,
[data-theme="dark"] .form-group textarea {
    background: var(--bg-card);
    color: var(--text-dark);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--header-h) + 20px);
}

body {
    margin: 0;
    font-family: var(--font-main);
    font-size: 1rem;
    line-height: 1.65;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}

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

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

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

h1, h2, h3, h4 {
    color: var(--text-dark);
    line-height: 1.25;
    margin-top: 0;
}

p { margin-top: 0; }

ul { padding-left: 1.2rem; }

.container {
    width: min(100% - 2rem, var(--container));
    margin-inline: auto;
}

.skip-link {
    position: absolute;
    top: -100px;
    left: 1rem;
    background: var(--accent-start);
    color: #fff;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
    z-index: 9999;
}

.skip-link:focus { top: 1rem; }

/* Clay / Neumorphism cards */
.clay-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    box-shadow: var(--neu-shadow);
    border: 1px solid rgba(255, 255, 255, 0.6);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.85rem 1.5rem;
    border-radius: var(--radius-sm);
    font-family: var(--font-main);
    font-weight: 600;
    font-size: 0.95rem;
    border: none;
    cursor: pointer;
    transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
    text-decoration: none;
    line-height: 1.2;
}

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

.btn-primary {
    background: linear-gradient(135deg, var(--accent-start), var(--accent-end));
    color: #fff;
    box-shadow: 0 4px 15px rgba(1, 35, 184, 0.3);
}

.btn-primary:hover { color: #fff; box-shadow: 0 6px 20px rgba(1, 35, 184, 0.4); }

.btn-secondary {
    background: var(--bg);
    color: var(--text-dark);
    box-shadow: var(--neu-shadow-sm);
}

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

.btn-ghost {
    background: transparent;
    color: var(--text);
    box-shadow: var(--neu-shadow-sm);
}

.btn-ghost:hover { color: var(--accent-start); }

.btn-whatsapp {
    background: #25d366;
    color: #fff;
    width: 100%;
    margin-top: 1rem;
}

.btn-whatsapp:hover { color: #fff; background: #1fb855; }

.btn-sm { padding: 0.6rem 1.1rem; font-size: 0.875rem; }

.btn-block { width: 100%; }

/* Header / Nav */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    height: var(--header-h);
    background: rgba(240, 240, 240, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(209, 209, 209, 0.4);
    transition: box-shadow var(--transition);
}

.site-header.is-scrolled { box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06); }

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-h);
    gap: 1rem;
}

.navbar-brand {
    display: flex;
    flex-direction: column;
    text-decoration: none;
    line-height: 1.2;
}

.brand-name {
    font-weight: 700;
    font-size: 1.05rem;
    background: linear-gradient(90deg, var(--accent-start), var(--accent-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.brand-sub {
    font-size: 0.7rem;
    color: var(--text-muted);
    font-weight: 500;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: var(--bg);
    border: none;
    padding: 0.6rem;
    border-radius: var(--radius-sm);
    box-shadow: var(--neu-shadow-sm);
    cursor: pointer;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-dark);
    transition: var(--transition);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-links {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 0.25rem;
    flex-wrap: wrap;
}

.nav-link {
    display: block;
    padding: 0.45rem 0.7rem;
    color: var(--text);
    font-size: 0.85rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    transition: background var(--transition), color var(--transition);
}

.nav-link:hover,
.nav-link.is-active {
    color: var(--accent-start);
    background: rgba(1, 35, 184, 0.06);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    border-radius: 50%;
    background: var(--bg);
    box-shadow: var(--neu-shadow-sm);
    cursor: pointer;
    color: var(--text-dark);
    font-size: 1.1rem;
    transition: var(--transition);
}

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

[data-theme="light"] .theme-icon--dark,
[data-theme="dark"] .theme-icon--light { display: none; }

/* Blog (estructura futura) */
.blog-page { padding-top: calc(var(--header-h) + 2rem); }

.blog-empty,
.blog-card { padding: 2rem; text-align: center; }

.blog-empty p { margin-bottom: 1.5rem; color: var(--text-muted); }

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.blog-card { text-align: left; }

.blog-card h2 { font-size: 1.15rem; margin-bottom: 0.5rem; }

.blog-card time {
    font-size: 0.8rem;
    color: var(--accent-start);
    font-weight: 600;
}

/* Sections */
.section {
    padding: 5rem 0;
}

.section-header {
    text-align: center;
    max-width: 680px;
    margin: 0 auto 3rem;
}

.section-label {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--accent-start);
    margin-bottom: 0.5rem;
}

.section-title {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.section-desc {
    color: var(--text-muted);
    font-size: 1.05rem;
}

/* Hero */
.hero {
    padding-top: calc(var(--header-h) + 3rem);
    padding-bottom: 4rem;
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-eyebrow {
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--accent-start);
    margin-bottom: 0.75rem;
}

.hero-name {
    font-family: var(--font-display);
    font-size: clamp(2.8rem, 6vw, 4.5rem);
    font-weight: 400;
    background: linear-gradient(90deg, var(--accent-start), var(--accent-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
    display: block;
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2.5vw, 1.35rem);
    font-weight: 600;
    color: var(--text-dark);
    margin: 1rem 0;
}

.hero-desc {
    color: var(--text-muted);
    max-width: 520px;
    margin-bottom: 1.75rem;
}

.hero-cta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.hero-meta {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.hero-meta .dot { margin: 0 0.4rem; }

.hero-visual {
    position: relative;
    display: flex;
    justify-content: center;
}

.hero-image-wrap {
    position: relative;
    padding: 1rem;
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.hero-image {
    width: 100%;
    max-width: 380px;
    aspect-ratio: 1;
    object-fit: cover;
    border-radius: calc(var(--radius-lg) - 8px);
}

.hero-badge {
    position: absolute;
    bottom: 1.5rem;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(8px);
    padding: 0.5rem 1rem;
    border-radius: 999px;
    font-size: 0.8rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    box-shadow: var(--neu-shadow-sm);
    white-space: nowrap;
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: #22c55e;
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.hero-float {
    position: absolute;
    padding: 0.75rem 1rem;
    font-size: 0.8rem;
}

.hero-float--1 { top: 5%; right: -5%; }
.hero-float--2 { bottom: 15%; left: -8%; }

.float-label {
    display: block;
    font-weight: 700;
    color: var(--accent-start);
    font-size: 0.75rem;
}

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

/* About */
.about-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.about-card { padding: 1.75rem; }

.about-card h3 {
    font-size: 1.15rem;
    margin-bottom: 0.75rem;
    color: var(--accent-start);
}

.about-list { margin: 0; }
.about-list li { margin-bottom: 0.35rem; }

/* Services */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1.5rem;
}

.service-card {
    padding: 1.75rem;
    transition: transform var(--transition), box-shadow var(--transition);
}

.service-card:hover {
    transform: translateY(-4px);
    box-shadow: 12px 12px 28px var(--shadow-dark), -12px -12px 28px var(--shadow-light);
}

.service-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(1, 35, 184, 0.1), rgba(70, 242, 252, 0.15));
    border-radius: 12px;
    color: var(--accent-start);
    margin-bottom: 1rem;
}

.service-card h3 { font-size: 1.05rem; margin-bottom: 0.5rem; }

.service-card p { font-size: 0.9rem; color: var(--text-muted); margin-bottom: 0.75rem; }

.service-result {
    font-size: 0.85rem;
    padding-top: 0.75rem;
    border-top: 1px solid rgba(209, 209, 209, 0.5);
}

/* Timeline */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
    padding-left: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(180deg, var(--accent-start), var(--accent-end));
    border-radius: 3px;
}

.timeline-item {
    position: relative;
    margin-bottom: 2rem;
}

.timeline-marker {
    position: absolute;
    left: -2rem;
    top: 1.5rem;
    width: 14px;
    height: 14px;
    background: var(--bg);
    border: 3px solid var(--accent-start);
    border-radius: 50%;
    transform: translateX(-5.5px);
    z-index: 1;
}

.timeline-item.is-highlight .timeline-marker {
    background: var(--accent-start);
    box-shadow: 0 0 0 4px rgba(1, 35, 184, 0.2);
}

.timeline-card { padding: 1.5rem 1.75rem; }

.timeline-period {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--accent-start);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.timeline-card h3 { font-size: 1.15rem; margin: 0.35rem 0; }

.timeline-company {
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.timeline-details {
    margin: 0;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.timeline-details li { margin-bottom: 0.35rem; }

/* Projects */
.project-filters {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.filter-btn {
    padding: 0.6rem 1.2rem;
    border: none;
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-main);
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: 999px;
    cursor: pointer;
    box-shadow: var(--neu-shadow-sm);
    transition: var(--transition);
}

.filter-btn:hover,
.filter-btn.is-active {
    background: linear-gradient(135deg, var(--accent-start), var(--accent-end));
    color: #fff;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.project-card {
    overflow: hidden;
    transition: transform var(--transition), opacity var(--transition);
}

.project-card.is-hidden {
    display: none;
}

.project-card:hover { transform: translateY(-4px); }

.project-image-wrap {
    position: relative;
    overflow: hidden;
    aspect-ratio: 16/10;
}

.project-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}

.project-card:hover .project-image { transform: scale(1.05); }

.project-category {
    position: absolute;
    top: 1rem;
    left: 1rem;
    background: rgba(1, 35, 184, 0.9);
    color: #fff;
    font-size: 0.7rem;
    font-weight: 600;
    padding: 0.35rem 0.75rem;
    border-radius: 999px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.project-body { padding: 1.5rem; }

.project-body h3 { font-size: 1.05rem; margin-bottom: 0.5rem; }

.project-body > p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.project-meta {
    display: grid;
    gap: 0.5rem;
    margin: 0 0 1rem;
    font-size: 0.85rem;
}

.project-meta dt {
    font-weight: 700;
    color: var(--text-dark);
    display: inline;
}

.project-meta dt::after { content: ': '; }

.project-meta dd {
    display: inline;
    margin: 0;
    color: var(--text-muted);
}

.project-meta div { display: block; }

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    font-weight: 600;
    font-size: 0.9rem;
}

/* Skills */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.25rem;
}

.skill-group { padding: 1.5rem; }

.skill-group h3 {
    font-size: 1rem;
    margin-bottom: 1rem;
    color: var(--accent-start);
}

.skill-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.skill-chip {
    display: inline-block;
    padding: 0.4rem 0.85rem;
    background: var(--bg);
    border-radius: 999px;
    font-size: 0.8rem;
    font-weight: 500;
    box-shadow: var(--neu-shadow-sm);
    transition: var(--transition);
}

.skill-chip:hover {
    background: linear-gradient(135deg, var(--accent-start), var(--accent-end));
    color: #fff;
}

/* Education */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.25rem;
}

.education-card {
    padding: 1.5rem;
    text-align: center;
}

.education-card.is-cert .education-icon { color: var(--gold); }

.education-icon {
    color: var(--accent-start);
    margin-bottom: 0.75rem;
    display: flex;
    justify-content: center;
}

.education-card h3 { font-size: 1rem; margin-bottom: 0.35rem; }

.education-institution {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 0.25rem;
}

.education-period {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--accent-start);
}

/* Teaching */
.teaching-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.teaching-card { padding: 1.75rem; }

.teaching-card h3 {
    color: var(--accent-start);
    margin-bottom: 0.35rem;
}

.teaching-modality {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.teaching-subjects {
    margin: 0;
    font-size: 0.9rem;
}

.teaching-subjects li { margin-bottom: 0.35rem; }

/* Contact */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.6fr;
    gap: 2rem;
    align-items: start;
}

.contact-card { padding: 1.75rem; }

.contact-card h3 { margin-bottom: 1rem; }

.contact-list {
    list-style: none;
    padding: 0;
    margin: 0 0 1rem;
}

.contact-list li {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
    font-size: 0.9rem;
}

.contact-social {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.contact-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg);
    box-shadow: var(--neu-shadow-sm);
    color: var(--text);
    transition: var(--transition);
}

.contact-social a:hover {
    color: var(--accent-start);
    transform: translateY(-2px);
}

.contact-form { padding: 2rem; }

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.form-group { margin-bottom: 1rem; }

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.4rem;
    color: var(--text-dark);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.85rem 1rem;
    font-family: var(--font-main);
    font-size: 0.95rem;
    color: var(--text-dark);
    background: var(--bg);
    border: none;
    border-radius: var(--radius-sm);
    box-shadow: var(--neu-inset);
    transition: box-shadow var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    box-shadow: var(--neu-inset), 0 0 0 3px rgba(1, 35, 184, 0.15);
}

.form-group input.is-invalid,
.form-group select.is-invalid,
.form-group textarea.is-invalid {
    box-shadow: var(--neu-inset), 0 0 0 2px rgba(231, 76, 60, 0.5);
}

.form-group textarea { resize: vertical; min-height: 120px; }

.form-feedback {
    padding: 0.85rem 1rem;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.form-feedback.is-success {
    background: rgba(7, 188, 12, 0.1);
    color: #0a5c0d;
    border: 1px solid rgba(7, 188, 12, 0.3);
}

.form-feedback.is-error {
    background: rgba(231, 76, 60, 0.1);
    color: #a8281e;
    border: 1px solid rgba(231, 76, 60, 0.3);
}

.form-note {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.75rem;
    text-align: center;
}

/* Footer */
.site-footer {
    background: var(--bg);
    border-top: 1px solid rgba(209, 209, 209, 0.5);
    padding: 3rem 0 1.5rem;
    margin-top: 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-name {
    font-size: 1.25rem;
    background: linear-gradient(90deg, var(--accent-start), var(--accent-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-tagline {
    color: var(--text-muted);
    font-size: 0.9rem;
    max-width: 320px;
}

.footer-links h4,
.footer-social h4 {
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
}

.footer-links ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li { margin-bottom: 0.4rem; }

.footer-links a {
    color: var(--text-muted);
    font-size: 0.9rem;
}

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

.social-links {
    display: flex;
    gap: 0.75rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg);
    box-shadow: var(--neu-shadow-sm);
    color: var(--text);
}

.social-links a:hover { color: var(--accent-start); }

.footer-bottom {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(209, 209, 209, 0.4);
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Back to top */
.back-to-top {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    width: 44px;
    height: 44px;
    border: none;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-start), var(--accent-end));
    color: #fff;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(1, 35, 184, 0.35);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: var(--transition);
    z-index: 900;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

/* Reveal animations */
.reveal {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 992px) {
    .hero-grid,
    .contact-grid {
        grid-template-columns: 1fr;
    }

    .hero-visual { order: -1; }

    .hero-float { display: none; }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    .nav-toggle { display: flex; }

    .nav-menu {
        position: fixed;
        top: var(--header-h);
        left: 0;
        right: 0;
        background: rgba(240, 240, 240, 0.97);
        backdrop-filter: blur(12px);
        flex-direction: column;
        padding: 1.5rem;
        gap: 1rem;
        transform: translateY(-120%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
        box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
        max-height: calc(100vh - var(--header-h));
        overflow-y: auto;
    }

    .nav-menu.is-open {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-links {
        flex-direction: column;
        width: 100%;
    }

    .nav-link {
        padding: 0.75rem 1rem;
        font-size: 1rem;
    }

    .nav-cta { width: 100%; }

    .nav-actions {
        width: 100%;
        justify-content: space-between;
    }

    .nav-toggle.is-active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
    .nav-toggle.is-active span:nth-child(2) { opacity: 0; }
    .nav-toggle.is-active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

    .about-grid,
    .form-row {
        grid-template-columns: 1fr;
    }

    .projects-grid {
        grid-template-columns: 1fr;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .section { padding: 3.5rem 0; }

    .hero { min-height: auto; padding-top: calc(var(--header-h) + 2rem); }
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }

    *, .reveal, .back-to-top, .btn, .project-card, .service-card {
        animation: none !important;
        transition: none !important;
    }

    .reveal {
        opacity: 1;
        transform: none;
    }
}

/* Focus visible */
:focus-visible {
    outline: 2px solid var(--accent-start);
    outline-offset: 2px;
}