/* ===========================
   CSS Custom Properties
   =========================== */
:root {
    /* Colors */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-secondary: #0f172a;
    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-bg: #ffffff;
    --color-bg-alt: #f8fafc;
    --color-border: #e2e8f0;
    --color-success: #10b981;
    --color-error: #ef4444;

    /* Gradient */
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);

    /* Typography */
    --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', 'Arial', sans-serif;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --font-weight-extrabold: 800;
    --font-weight-black: 900;

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

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Container */
    --container-max: 1200px;
}

/* ===========================
   Reset & Base Styles
   =========================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
}

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

a {
    color: inherit;
    text-decoration: none;
}

ul {
    list-style: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* ===========================
   Typography
   =========================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-weight-bold);
    line-height: 1.2;
    color: var(--color-secondary);
}

.lead {
    font-size: 1.25rem;
    font-weight: var(--font-weight-medium);
    color: var(--color-text);
    margin-bottom: var(--space-md);
}

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

/* ===========================
   Navigation
   =========================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    transition: transform var(--transition-base);
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
}

.logo {
    font-size: 1.5rem;
    font-weight: var(--font-weight-black);
    color: var(--color-primary);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 6px;
    padding: var(--space-xs);
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--color-secondary);
    transition: all var(--transition-base);
}

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

.nav-links a {
    font-weight: var(--font-weight-medium);
    color: var(--color-text);
    transition: color var(--transition-fast);
}

.nav-links a:hover {
    color: var(--color-primary);
}

.nav-cta {
    padding: var(--space-xs) var(--space-md);
    background-color: var(--color-primary);
    color: white !important;
    border-radius: var(--radius-md);
    transition: background-color var(--transition-fast);
}

.nav-cta:hover {
    background-color: var(--color-primary-dark);
}

/* ===========================
   Buttons
   =========================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.875rem 2rem;
    font-size: 1rem;
    font-weight: var(--font-weight-semibold);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    cursor: pointer;
    white-space: nowrap;
}

.btn-primary {
    background-color: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-text);
    border: 2px solid var(--color-border);
}

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

.btn-full {
    width: 100%;
}

/* ===========================
   Section Styles
   =========================== */
section {
    padding: var(--space-3xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.section-label {
    display: inline-block;
    padding: var(--space-xs) var(--space-md);
    background-color: var(--color-bg-alt);
    color: var(--color-primary);
    font-size: 0.875rem;
    font-weight: var(--font-weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: var(--radius-md);
    margin-bottom: var(--space-md);
}

.section-title {
    font-size: 2.5rem;
    font-weight: var(--font-weight-extrabold);
    margin-bottom: var(--space-md);
}

/* ===========================
   Hero Section
   =========================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    background: linear-gradient(135deg, #f8fafc 0%, #ffffff 100%);
}

.hero-content {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
}

.hero-label {
    display: inline-block;
    padding: var(--space-xs) var(--space-md);
    background-color: var(--color-bg-alt);
    color: var(--color-primary);
    font-size: 0.875rem;
    font-weight: var(--font-weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: var(--radius-md);
    margin-bottom: var(--space-lg);
}

.hero-title {
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: var(--font-weight-black);
    line-height: 1.1;
    margin-bottom: var(--space-lg);
    letter-spacing: -0.02em;
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--color-text-light);
    max-width: 700px;
    margin: 0 auto var(--space-xl);
    line-height: 1.7;
}

.hero-cta {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* ===========================
   About Section
   =========================== */
.about {
    background-color: var(--color-bg);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-2xl);
    align-items: start;
}

.about-text p {
    margin-bottom: var(--space-md);
    color: var(--color-text-light);
    line-height: 1.8;
}

.about-timeline {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.timeline-item {
    padding: var(--space-lg);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--color-primary);
    transition: transform var(--transition-base);
}

.timeline-item:hover {
    transform: translateX(4px);
}

.timeline-period {
    font-size: 0.875rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-primary);
    margin-bottom: var(--space-xs);
}

.timeline-role {
    font-size: 1.125rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-secondary);
    margin-bottom: 0.25rem;
}

.timeline-company {
    font-weight: var(--font-weight-medium);
    color: var(--color-text);
    margin-bottom: var(--space-xs);
}

.timeline-description {
    font-size: 0.9375rem;
    color: var(--color-text-light);
}

/* ===========================
   Expertise Section
   =========================== */
.expertise {
    background-color: var(--color-bg-alt);
}

.expertise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-lg);
}

.expertise-card {
    padding: var(--space-xl);
    background-color: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.expertise-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.expertise-icon {
    width: 48px;
    height: 48px;
    margin-bottom: var(--space-md);
    color: var(--color-primary);
}

.expertise-icon svg {
    width: 100%;
    height: 100%;
}

.expertise-card h3 {
    font-size: 1.25rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--space-sm);
}

.expertise-card p {
    color: var(--color-text-light);
    line-height: 1.7;
}

/* ===========================
   Projects Section
   =========================== */
.projects {
    background-color: var(--color-bg);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--space-xl);
}

.project-card {
    background-color: white;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.project-image {
    height: 200px;
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-placeholder {
    font-size: 2rem;
    font-weight: var(--font-weight-black);
    color: white;
}

.project-content {
    padding: var(--space-lg);
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
    margin-bottom: var(--space-md);
}

.tag {
    padding: 0.25rem 0.75rem;
    background-color: var(--color-bg-alt);
    color: var(--color-primary);
    font-size: 0.75rem;
    font-weight: var(--font-weight-semibold);
    border-radius: var(--radius-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.project-card h3 {
    font-size: 1.375rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--space-sm);
}

.project-card p {
    color: var(--color-text-light);
    line-height: 1.7;
    margin-bottom: var(--space-md);
}

.project-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--space-md);
    border-top: 1px solid var(--color-border);
    font-size: 0.875rem;
    color: var(--color-text-light);
}

/* ===========================
   Contact Section
   =========================== */
.contact {
    background-color: var(--color-bg-alt);
}

.contact-wrapper {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.contact-info {
    margin: 0 auto;
}

.contact-description {
    font-size: 1.125rem;
    color: var(--color-text-light);
    line-height: 1.8;
    margin-bottom: var(--space-xl);
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    align-items: center;
    margin-bottom: var(--space-xl);
}

.contact-cta {
    margin-top: var(--space-xl);
}

.btn-large {
    padding: 1.125rem 2.5rem;
    font-size: 1.125rem;
}

.contact-item {
    display: flex;
    gap: var(--space-md);
    align-items: start;
}

.contact-item svg {
    width: 24px;
    height: 24px;
    color: var(--color-primary);
    flex-shrink: 0;
}

.contact-label {
    font-size: 0.875rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.25rem;
}

.contact-item a {
    color: var(--color-primary);
    transition: opacity var(--transition-fast);
}

.contact-item a:hover {
    opacity: 0.8;
}

/* ===========================
   Footer
   =========================== */
.footer {
    background-color: var(--color-secondary);
    color: white;
    padding: var(--space-3xl) 0 var(--space-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--space-2xl);
    margin-bottom: var(--space-xl);
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.7);
    margin-top: var(--space-sm);
}

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

.footer-column h4 {
    color: white;
    font-size: 1rem;
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--space-md);
}

.footer-column ul {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.footer-column a {
    color: rgba(255, 255, 255, 0.7);
    transition: color var(--transition-fast);
}

.footer-column a:hover {
    color: white;
}

.footer-bottom {
    padding-top: var(--space-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    color: rgba(255, 255, 255, 0.5);
}

/* ===========================
   Responsive Design
   =========================== */
@media (max-width: 968px) {
    .about-content {
        grid-template-columns: 1fr;
    }

    .section-title {
        font-size: 2rem;
    }
}

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

    .nav-links {
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: var(--space-lg);
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
    }

    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .hero-cta {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

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

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

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

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-sm);
    }

    .section-title {
        font-size: 1.75rem;
    }

    .hero-description {
        font-size: 1.125rem;
    }
}

/* ===========================
   Animations
   =========================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}