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

:root {
    /* Typography */
    --font-stack: 'Ubuntu', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-heading: 'Ubuntu', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-xs: 1.4rem;
    --font-size-sm: 1.6rem;
    --font-size-base: 1.8rem;
    --font-size-lg: 2.2rem;
    --font-size-xl: 2.8rem;
    --font-size-2xl: 3.6rem;
    --font-size-3xl: 4.8rem;
    --font-size-4xl: 6.4rem;
    
    /* Colors - Blue Theme */
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --accent: #0ea5e9;
    --accent-light: #38bdf8;
    
    /* Light Theme */
    --bg: #f8fafc;
    --surface: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --border: rgba(15, 23, 42, 0.1);
    --card-bg: #ffffff;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Spacing */
    --spacing-xs: 0.8rem;
    --spacing-sm: 1.6rem;
    --spacing-md: 2.4rem;
    --spacing-lg: 3.2rem;
    --spacing-xl: 4.8rem;
    --spacing-2xl: 6.4rem;
    --spacing-3xl: 9.6rem;
    
    /* Container */
    --container-width: 1200px;
    --container-padding: 2.4rem;
    
    /* Border Radius */
    --radius-sm: 0.8rem;
    --radius-md: 1.2rem;
    --radius-lg: 1.6rem;
    --radius-xl: 2.4rem;
}

html[data-theme="dark"] {
    --bg: #0f172a;
    --surface: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border: rgba(241, 245, 249, 0.1);
    --card-bg: #1e293b;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
}

html {
    font-size: 62.5%;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-stack);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg);
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow-x: hidden;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg);
}

::-webkit-scrollbar-thumb {
    background: var(--primary);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* Container */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }

p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
}

a {
    color: inherit;
    text-decoration: none;
    transition: all 0.2s ease;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: 1.2rem 2.4rem;
    font-size: var(--font-size-base);
    font-weight: 500;
    border-radius: var(--radius-md);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: var(--font-stack);
}

.btn--primary {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
}

.btn--primary:hover {
    background: var(--primary-dark);
    border-color: var(--primary-dark);
    box-shadow: var(--shadow-lg);
}

.btn--outline {
    background: transparent;
    color: var(--primary);
    border-color: var(--primary);
}

.btn--outline:hover {
    background: var(--primary);
    color: #ffffff;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--surface);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
}

.navbar__container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 1.6rem var(--container-padding);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
}

.navbar__menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    list-style: none;
    flex: 1;
    justify-content: center;
}

.navbar__link {
    font-size: var(--font-size-base);
    font-weight: 500;
    color: var(--text-secondary);
    padding: 0.8rem 1.2rem;
    border-radius: var(--radius-sm);
    transition: all 0.2s ease;
    min-height: 4.4rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.navbar__link:hover {
    color: var(--primary);
    background: rgba(37, 99, 235, 0.1);
}

.navbar__actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.theme-toggle {
    position: relative;
    width: 5.2rem;
    height: 2.8rem;
    background: var(--border);
    border: 1px solid var(--border);
    border-radius: 10rem;
    cursor: pointer;
    transition: all 0.3s ease;
    padding: 0;
}

.theme-toggle__slider {
    position: absolute;
    top: 0.3rem;
    left: 0.3rem;
    width: 2.2rem;
    height: 2.2rem;
    background: var(--surface);
    border-radius: 50%;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

html[data-theme="dark"] .theme-toggle {
    background: var(--primary);
    border-color: var(--primary);
}

html[data-theme="dark"] .theme-toggle__slider {
    transform: translateX(2.4rem);
    background: #ffffff;
}

.theme-toggle:hover {
    opacity: 0.8;
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 0.5rem;
    width: 3.2rem;
    height: 3.2rem;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
}

.mobile-toggle span {
    display: block;
    width: 100%;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.mobile-toggle[aria-expanded="true"] span:nth-child(1) {
    transform: rotate(45deg) translate(0.6rem, 0.6rem);
}

.mobile-toggle[aria-expanded="true"] span:nth-child(2) {
    opacity: 0;
}

.mobile-toggle[aria-expanded="true"] span:nth-child(3) {
    transform: rotate(-45deg) translate(0.6rem, -0.6rem);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 8rem;
    padding-bottom: var(--spacing-3xl);
    position: relative;
    overflow: hidden;
    background: 
        radial-gradient(circle at 20% 50%, rgba(37, 99, 235, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(14, 165, 233, 0.08) 0%, transparent 50%),
        linear-gradient(135deg, var(--bg) 0%, rgba(37, 99, 235, 0.03) 50%, var(--bg) 100%);
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        radial-gradient(circle at 1px 1px, rgba(37, 99, 235, 0.15) 1px, transparent 0);
    background-size: 40px 40px;
    opacity: 0.3;
    pointer-events: none;
}

html[data-theme="dark"] .hero {
    background: 
        radial-gradient(circle at 20% 50%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(14, 165, 233, 0.12) 0%, transparent 50%),
        linear-gradient(135deg, var(--bg) 0%, rgba(37, 99, 235, 0.05) 50%, var(--bg) 100%);
}

.hero__container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
    position: relative;
    z-index: 1;
}

.hero__content {
    max-width: 72rem;
    text-align: center;
    margin: 0 auto;
}

.hero__badge {
    display: inline-block;
    padding: 0.8rem 1.6rem;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    border-radius: 10rem;
    font-size: var(--font-size-sm);
    font-weight: 500;
    margin-bottom: var(--spacing-lg);
    border: 1px solid rgba(37, 99, 235, 0.2);
}

.hero__title {
    margin-bottom: var(--spacing-lg);
}

.hero__greeting {
    display: block;
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    font-weight: 400;
    margin-bottom: var(--spacing-sm);
}

.hero__name {
    display: block;
    font-size: var(--font-size-4xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
}

.hero__description {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    max-width: 60rem;
    margin-left: auto;
    margin-right: auto;
}

.hero__tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    justify-content: center;
    margin-bottom: var(--spacing-xl);
}

.tag {
    padding: 0.6rem 1.2rem;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 10rem;
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    font-weight: 500;
}

.hero__actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* Sections */
.section {
    padding: var(--spacing-3xl) 0;
}

.section__header {
    margin-bottom: var(--spacing-3xl);
}

.section__header-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.section__label {
    display: inline-block;
    padding: 0.6rem 1.2rem;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    border-radius: 10rem;
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.section__title {
    margin-bottom: 0;
}

.section__link {
    color: var(--primary);
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.section__link:hover {
    gap: var(--spacing-sm);
}

/* Projects */
.projects {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3xl);
}

.project {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
    padding: var(--spacing-xl);
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.project:hover {
    box-shadow: var(--shadow-lg);
}

.project--featured {
    grid-template-columns: 1.2fr 1fr;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.05) 0%, rgba(14, 165, 233, 0.03) 100%);
}

.project:nth-child(even) {
    direction: rtl;
}

.project:nth-child(even) > * {
    direction: ltr;
}

.project__image {
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.project__image img {
    width: 100%;
    height: auto;
    display: block;
    transition: transform 0.3s ease;
}

.project:hover .project__image img {
    transform: scale(1.05);
}

.project__content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.project__meta {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-sm);
}

.project__category {
    padding: 0.4rem 1rem;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    border-radius: 10rem;
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    width: fit-content;
}

.project__users {
    padding: 0.4rem 1rem;
    background: rgba(14, 165, 233, 0.1);
    color: var(--accent);
    border-radius: 10rem;
    font-size: var(--font-size-xs);
    font-weight: 600;
}

.project__title {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-sm);
}

.project__description {
    color: var(--text-secondary);
    line-height: 1.7;
}

.project__features {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    margin: var(--spacing-md) 0;
}

.project__features li {
    padding-left: 2rem;
    position: relative;
    color: var(--text-secondary);
}

.project__features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary);
    font-weight: 700;
}

.project__tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-sm);
}

.project__tags span {
    padding: 0.4rem 1rem;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 10rem;
    font-size: var(--font-size-xs);
    color: var(--text-secondary);
}

.project__link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--primary);
    font-weight: 600;
    margin-top: var(--spacing-sm);
    transition: gap 0.2s ease;
}

.project__link:hover {
    gap: var(--spacing-sm);
}

/* Skills */
.skills {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3xl);
}

.skills__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.skill-card {
    padding: var(--spacing-xl);
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.skill-card:hover {
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.skill-card__icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

.skill-card__title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-md);
}

.skill-card__description {
    color: var(--text-secondary);
    line-height: 1.7;
}

.skills__badges {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    padding: var(--spacing-xl);
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border);
}

.skill-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.8rem 1.6rem;
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-primary);
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10rem;
    transition: all 0.3s ease;
    cursor: default;
    white-space: nowrap;
}

.skill-badge:hover {
    background: var(--primary);
    border-color: var(--primary);
    color: #ffffff;
    box-shadow: var(--shadow);
}

/* Posts */
.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.post-card {
    padding: var(--spacing-xl);
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
}

.post-card:hover {
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.post-card__header {
    margin-bottom: var(--spacing-md);
}

.post-card__badge {
    display: inline-block;
    padding: 0.4rem 1rem;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    border-radius: 10rem;
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.post-card__content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.post-card__title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.post-card__excerpt {
    color: var(--text-secondary);
    line-height: 1.7;
    flex: 1;
}

.post-card__link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--primary);
    font-weight: 600;
    margin-top: auto;
    transition: gap 0.2s ease;
}

.post-card__link:hover {
    gap: var(--spacing-sm);
}

/* About */
.about {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
}

.about__text {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.about__text p {
    font-size: var(--font-size-lg);
    line-height: 1.8;
    color: var(--text-secondary);
}

.about__image {
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.about__image img {
    width: 100%;
    height: auto;
    display: block;
}

/* Contact */
.contact {
    max-width: 60rem;
    margin: 0 auto;
    text-align: center;
}

.contact__description {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.contact__actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* Footer */
.footer {
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
    border-top: 1px solid var(--border);
    margin-top: var(--spacing-3xl);
}

.footer__content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.footer__copyright {
    color: var(--text-muted);
    font-size: var(--font-size-sm);
    margin: 0;
}

.footer__social {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.footer__social-link {
    width: 4rem;
    height: 4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    background: var(--card-bg);
    border: 1px solid var(--border);
    transition: all 0.2s ease;
}

.footer__social-link:hover {
    background: var(--primary);
    border-color: var(--primary);
}

.footer__social-link img {
    width: 2rem;
    height: 2rem;
    filter: brightness(0) saturate(100%);
    transition: filter 0.2s ease;
}

.footer__social-link:hover img {
    filter: brightness(0) invert(1);
}

/* Back to Top */
.back-to-top {
    position: fixed;
    bottom: 3rem;
    right: 3rem;
    width: 5rem;
    height: 5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary);
    color: #ffffff;
    border-radius: 50%;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 999;
}

.back-to-top:hover {
    background: var(--primary-dark);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top svg {
    width: 2rem;
    height: 2rem;
}

/* Responsive */
@media (max-width: 968px) {
    .navbar__menu {
        position: fixed;
        top: 7.2rem;
        left: 0;
        right: 0;
        background: var(--surface);
        flex-direction: column;
        padding: var(--spacing-xl);
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
        max-height: calc(100vh - 7.2rem);
        overflow-y: auto;
    }

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

    .mobile-toggle {
        display: flex;
        justify-content: center;
    }

    .project,
    .project--featured {
        grid-template-columns: 1fr;
    }

    .project:nth-child(even) {
        direction: ltr;
    }

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

    .hero__name {
        font-size: var(--font-size-3xl);
    }

    .section__title {
        font-size: var(--font-size-2xl);
    }
}

@media (max-width: 640px) {
    :root {
        --font-size-4xl: 4.8rem;
        --font-size-3xl: 3.6rem;
        --font-size-2xl: 2.8rem;
        --container-padding: 1.6rem;
        --spacing-3xl: 6.4rem;
        --spacing-2xl: 4.8rem;
    }

    .hero {
        padding-top: 10rem;
        padding-bottom: var(--spacing-2xl);
    }

    .hero__name {
        font-size: var(--font-size-2xl);
    }

    .hero__description {
        font-size: var(--font-size-base);
    }

    .hero__tags {
        gap: var(--spacing-xs);
    }

    .tag {
        font-size: var(--font-size-xs);
        padding: 0.4rem 0.8rem;
    }

    .hero__actions,
    .contact__actions {
        flex-direction: column;
        width: 100%;
    }

    .btn {
        width: 100%;
        padding: 1.4rem 2.4rem;
        min-height: 4.8rem;
    }

    .section {
        padding: var(--spacing-2xl) 0;
    }

    .section__header {
        margin-bottom: var(--spacing-2xl);
    }

    .project {
        padding: var(--spacing-lg);
        gap: var(--spacing-xl);
    }

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

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

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

    .navbar__container {
        padding: 1.2rem var(--container-padding);
    }

    .theme-toggle {
        width: 4.8rem;
        height: 2.6rem;
    }

    .theme-toggle__slider {
        width: 2rem;
        height: 2rem;
    }

    html[data-theme="dark"] .theme-toggle__slider {
        transform: translateX(2.2rem);
    }

    .mobile-toggle {
        width: 3.2rem;
        height: 3.2rem;
    }

    .back-to-top {
        width: 4.4rem;
        height: 4.4rem;
        bottom: 2rem;
        right: 2rem;
    }
}

body.menu-open {
    overflow: hidden;
}

/* Back to top visibility */
@media (min-width: 768px) {
    .back-to-top {
        display: flex;
    }
}