/* ========================================
   Variables & Reset
   ======================================== */
:root {
    --color-bg: #0a0a0b;
    --color-bg-alt: #111113;
    --color-bg-card: #18181b;
    --color-bg-card-hover: #1f1f23;
    --color-border: #27272a;
    --color-border-light: #3f3f46;
    --color-text: #fafafa;
    --color-text-secondary: #a1a1aa;
    --color-text-muted: #71717a;
    --color-primary: #6366f1;
    --color-primary-hover: #818cf8;
    --color-primary-glow: rgba(99, 102, 241, 0.15);
    --color-accent: #22d3ee;

    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.75rem;
    --font-size-5xl: 3.5rem;

    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;

    --radius-sm: 0.375rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;

    --transition: 0.2s ease;
    --nav-height: 4rem;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--nav-height);
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

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

ul {
    list-style: none;
}

/* ========================================
   Layout
   ======================================== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* ========================================
   Section Header
   ======================================== */
.section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
}

.section-header__label {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-primary-hover);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-xs);
}

.section-header__title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--color-text);
}

/* ========================================
   Navigation
   ======================================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    z-index: 1000;
    background: rgba(10, 10, 11, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
    transition: border-color var(--transition);
}

.nav--scrolled {
    border-bottom-color: var(--color-border);
}

.nav__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav__logo {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.nav__menu {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
}

.nav__link {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: color var(--transition);
}

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

.nav__link--cta {
    color: var(--color-bg);
    background: var(--color-text);
    padding: 0.5rem 1.25rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.nav__link--cta:hover {
    color: var(--color-bg);
    background: var(--color-text-secondary);
}

.nav__toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav__toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: transform var(--transition), opacity var(--transition);
}

.nav__toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav__toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav__toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.75rem;
    font-size: var(--font-size-sm);
    font-weight: 600;
    font-family: var(--font-family);
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    gap: var(--space-xs);
}

.btn--primary {
    background: var(--color-primary);
    color: #fff;
    box-shadow: 0 0 20px var(--color-primary-glow);
}

.btn--primary:hover {
    background: var(--color-primary-hover);
    color: #fff;
    box-shadow: 0 0 30px var(--color-primary-glow);
    transform: translateY(-1px);
}

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

.btn--outline:hover {
    color: var(--color-text);
    border-color: var(--color-border-light);
    background: var(--color-bg-card);
}

.btn--full {
    width: 100%;
}

/* ========================================
   Hero
   ======================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: calc(var(--nav-height) + var(--space-3xl)) 0 var(--space-3xl);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(ellipse at 30% 20%, var(--color-primary-glow) 0%, transparent 50%),
                radial-gradient(ellipse at 70% 80%, rgba(34, 211, 238, 0.05) 0%, transparent 50%);
    pointer-events: none;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: center;
    position: relative;
}

.hero__label {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-primary-hover);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-md);
}

.hero__title {
    font-size: var(--font-size-5xl);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: var(--space-lg);
    background: linear-gradient(135deg, var(--color-text) 0%, var(--color-text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero__subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    line-height: 1.7;
    max-width: 500px;
    margin-bottom: var(--space-xl);
}

.hero__actions {
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
}

/* Code block */
.hero__code {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.3);
}

.hero__code-header {
    display: flex;
    gap: 6px;
    padding: 12px 16px;
    background: var(--color-bg-alt);
    border-bottom: 1px solid var(--color-border);
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.dot--red { background: #ef4444; }
.dot--yellow { background: #eab308; }
.dot--green { background: #22c55e; }

.hero__code-body {
    padding: var(--space-lg);
    font-size: var(--font-size-sm);
    line-height: 1.8;
    font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
    overflow-x: auto;
}

.hero__code-body code {
    color: var(--color-text-secondary);
}

.code-keyword { color: #c084fc; }
.code-variable { color: var(--color-accent); }
.code-class { color: #fbbf24; }
.code-method { color: #818cf8; }
.code-string { color: #34d399; }

/* ========================================
   Services
   ======================================== */
.services {
    padding: var(--space-4xl) 0;
}

.services__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
}

.service-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
    transition: all var(--transition);
}

.service-card:hover {
    background: var(--color-bg-card-hover);
    border-color: var(--color-border-light);
    transform: translateY(-2px);
}

.service-card__icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-primary-glow);
    color: var(--color-primary-hover);
    border-radius: var(--radius-md);
    margin-bottom: var(--space-lg);
}

.service-card__title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-text);
}

.service-card__text {
    color: var(--color-text-secondary);
    line-height: 1.7;
    font-size: var(--font-size-sm);
}

/* ========================================
   About
   ======================================== */
.about {
    padding: var(--space-4xl) 0;
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.about__layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: start;
}

.about__text {
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-md);
}

.about__stats {
    display: flex;
    gap: var(--space-2xl);
    margin-top: var(--space-xl);
}

.stat {
    display: flex;
    flex-direction: column;
}

.stat__number {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.about__skills {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
}

.about__skills-title {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.about__skills-title:not(:first-child) {
    margin-top: var(--space-xl);
}

.skills-grid {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
}

.skill-tag {
    padding: 0.375rem 0.875rem;
    background: var(--color-primary-glow);
    color: var(--color-primary-hover);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.about__certs {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.about__certs li {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    padding-left: var(--space-md);
    position: relative;
}

.about__certs li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.6em;
    width: 6px;
    height: 6px;
    background: var(--color-primary);
    border-radius: 50%;
}

/* ========================================
   Portfolio / Reference
   ======================================== */
.portfolio {
    padding: var(--space-4xl) 0;
}

.portfolio__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
}

.portfolio-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition);
}

.portfolio-card:hover {
    border-color: var(--color-border-light);
    transform: translateY(-2px);
}

.portfolio-card__content {
    padding: var(--space-2xl);
}

.portfolio-card__title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-text);
}

.portfolio-card__text {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    line-height: 1.7;
    margin-bottom: var(--space-lg);
}

.portfolio-card__tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
}

.portfolio-card__tags span {
    padding: 0.25rem 0.625rem;
    font-size: var(--font-size-xs);
    background: var(--color-bg-alt);
    color: var(--color-text-muted);
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
}

/* ========================================
   Contact
   ======================================== */
.contact {
    padding: var(--space-4xl) 0;
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
}

.contact__layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: start;
}

.contact__text {
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-xl);
}

.contact__details {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.contact__detail {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    color: var(--color-text-secondary);
}

.contact__detail svg {
    color: var(--color-primary-hover);
    flex-shrink: 0;
}

.contact__detail a {
    color: var(--color-text-secondary);
}

.contact__detail a:hover {
    color: var(--color-text);
}

.contact__form {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
}

.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xs);
}

.form-input {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: var(--font-size-base);
    font-family: var(--font-family);
    color: var(--color-text);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: border-color var(--transition), box-shadow var(--transition);
    outline: none;
}

.form-input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
}

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

.form-alert {
    padding: 0.875rem 1rem;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    margin-bottom: var(--space-lg);
}

.form-alert--success {
    background: rgba(34, 197, 94, 0.1);
    border: 1px solid rgba(34, 197, 94, 0.3);
    color: #4ade80;
}

.form-alert--error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #f87171;
}

/* ========================================
   Footer
   ======================================== */
.footer {
    padding: var(--space-xl) 0;
    border-top: 1px solid var(--color-border);
}

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

.footer__brand {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.footer__nav {
    display: flex;
    gap: var(--space-lg);
}

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

.footer__nav a:hover {
    color: var(--color-text);
}

/* ========================================
   Animations
   ======================================== */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero__subtitle {
        max-width: 100%;
    }

    .hero__actions {
        justify-content: center;
    }

    .hero__visual {
        max-width: 500px;
        margin: 0 auto;
    }

    .about__layout,
    .contact__layout {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    :root {
        --font-size-5xl: 2.5rem;
        --font-size-4xl: 2rem;
        --font-size-3xl: 1.5rem;
    }

    .nav__toggle {
        display: flex;
    }

    .nav__menu {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        right: 0;
        background: var(--color-bg);
        border-bottom: 1px solid var(--color-border);
        flex-direction: column;
        padding: var(--space-lg);
        gap: var(--space-md);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: transform 0.3s ease, opacity 0.3s ease;
    }

    .nav__menu.open {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }

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

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

    .about__stats {
        justify-content: space-between;
    }

    .footer__content {
        flex-direction: column;
        gap: var(--space-md);
        text-align: center;
    }
}

@media (max-width: 480px) {
    :root {
        --font-size-5xl: 2rem;
    }

    .hero__actions {
        flex-direction: column;
    }

    .btn--full-mobile {
        width: 100%;
    }

    .about__stats {
        flex-direction: column;
        gap: var(--space-md);
        align-items: center;
        text-align: center;
    }
}