/* ===================================
   Apple-Inspired Design System
   =================================== */

/* CSS Variables - Refined Palette */
:root {
    /* Colors */
    --color-black: #000000;
    --color-black-rgb: 0, 0, 0;
    --color-dark-gray: #1d1d1f;
    --color-gray: #86868b;
    --color-light-gray: #f5f5f7;
    --color-white: #ffffff;
    --color-accent: #0066cc;
    --color-accent-hover: #004499;

    /* Backgrounds */
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f7;
    --bg-tertiary: #fbfbfd;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, "SF Pro SC", "SF Pro Text", "Helvetica Neue", "Helvetica", "Arial", sans-serif;
    --font-family-display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro SC", "Helvetica Neue", sans-serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 5rem;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --radius-xl: 24px;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.16);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.2);

    /* Transitions */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);

    /* Z-index */
    --z-nav: 1000;
    --z-dropdown: 900;
    --z-modal: 1100;
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-family);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-dark-gray);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

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

ul {
    list-style: none;
}

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

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

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ===================================
   Navigation
   =================================== */
.global-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    z-index: var(--z-nav);
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}

.nav-container {
    max-width: 1000px;
    margin: 0 auto;
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem var(--spacing-lg);
    height: 48px;
}

.nav-logo {
    width: 20px;
    height: 24px;
    color: var(--color-dark-gray);
    transition: transform var(--transition-base);
}

.nav-logo:hover {
    transform: scale(1.05);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--color-dark-gray);
    letter-spacing: -0.01em;
    transition: color var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-accent);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    padding: 4px;
}

.nav-toggle span {
    width: 18px;
    height: 1.5px;
    background-color: var(--color-dark-gray);
    transition: all var(--transition-base);
}

/* Mobile Menu */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: var(--spacing-md);
        gap: 0;
        border-bottom: 1px solid rgba(0, 0, 0, 0.08);
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-menu li {
        width: 100%;
        border-bottom: 1px solid var(--color-light-gray);
    }

    .nav-link {
        display: block;
        padding: var(--spacing-sm) 0;
        font-size: 1rem;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translateY(3px);
    }

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

/* ===================================
   Hero Section
   =================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 120px var(--spacing-lg) 60px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
}

.hero-gradient {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    opacity: 0.03;
}

.hero-particles {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        radial-gradient(2px 2px at 20px 30px, rgba(0, 0, 0, 0.1), transparent),
        radial-gradient(2px 2px at 40px 70px, rgba(0, 0, 0, 0.08), transparent),
        radial-gradient(1px 1px at 90px 40px, rgba(0, 0, 0, 0.05), transparent),
        radial-gradient(2px 2px at 160px 120px, rgba(0, 0, 0, 0.1), transparent);
    background-size: 200px 200px;
    animation: particles 20s linear infinite;
}

@keyframes particles {
    0% { transform: translateY(0); }
    100% { transform: translateY(-200px); }
}

.hero-content {
    text-align: center;
    max-width: 800px;
    animation: fadeInUp 1s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-title {
    font-size: clamp(3rem, 10vw, 6rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.05;
    margin-bottom: var(--spacing-md);
    color: var(--color-dark-gray);
}

.title-line {
    display: block;
    opacity: 0;
    animation: fadeInUp 0.8s ease-out forwards;
}

.title-line:nth-child(1) { animation-delay: 0.1s; }
.title-line:nth-child(2) { animation-delay: 0.2s; }
.title-line:nth-child(3) { animation-delay: 0.3s; }

.title-accent {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.5rem);
    font-weight: 400;
    color: var(--color-gray);
    letter-spacing: 0.01em;
    margin-bottom: var(--spacing-xl);
    opacity: 0;
    animation: fadeInUp 0.8s ease-out 0.4s forwards;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    opacity: 0;
    animation: fadeInUp 0.8s ease-out 0.6s forwards;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    font-size: 1rem;
    font-weight: 500;
    border-radius: 980px;
    transition: all var(--transition-base);
    cursor: pointer;
}

.btn-primary {
    background-color: var(--color-accent);
    color: var(--color-white);
}

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

.btn-secondary {
    background-color: var(--color-light-gray);
    color: var(--color-dark-gray);
}

.btn-secondary:hover {
    background-color: #e8e8ed;
    transform: translateY(-2px);
}

.btn-arrow {
    transition: transform var(--transition-base);
}

.btn:hover .btn-arrow {
    transform: translateX(4px);
}

/* Scroll Indicator */
.hero-scroll {
    position: absolute;
    bottom: var(--spacing-xl);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-gray);
    font-size: 0.75rem;
}

.scroll-text {
    letter-spacing: 0.05em;
}

.scroll-line {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, var(--color-gray), transparent);
    animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
    0%, 100% { transform: scaleY(1); opacity: 1; }
    50% { transform: scaleY(0.5); opacity: 0.5; }
}

/* ===================================
   Section Styles
   =================================== */
section {
    padding: var(--spacing-2xl) 0;
}

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

.section-title {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-sm);
    color: var(--color-dark-gray);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--color-gray);
    letter-spacing: 0.02em;
}

/* ===================================
   Articles Section
   =================================== */
.articles-section {
    background-color: var(--bg-secondary);
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.article-card {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-base);
    cursor: pointer;
}

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

.article-card.featured {
    grid-column: span 2;
}

@media (max-width: 768px) {
    .article-card.featured {
        grid-column: span 1;
    }
}

.article-image {
    position: relative;
    height: 240px;
    overflow: hidden;
}

.image-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform var(--transition-slow);
}

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

.article-badge {
    position: absolute;
    top: var(--spacing-md);
    left: var(--spacing-md);
    padding: 0.375rem 0.875rem;
    background: var(--color-white);
    border-radius: 980px;
    font-size: 0.75rem;
    font-weight: 600;
    box-shadow: var(--shadow-sm);
}

.article-content {
    padding: var(--spacing-lg);
}

.article-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.article-category {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.article-date {
    font-size: 0.75rem;
    color: var(--color-gray);
}

.article-title {
    font-size: 1.375rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: var(--spacing-sm);
    line-height: 1.3;
}

.article-excerpt {
    font-size: 1rem;
    color: var(--color-gray);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

.article-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-accent);
    transition: gap var(--transition-base);
}

.article-link:hover {
    gap: 0.75rem;
}

.article-link svg {
    transition: transform var(--transition-base);
}

.article-link:hover svg {
    transform: translateX(4px);
}

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

.projects-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
}

.gradient-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(180deg,
        var(--bg-primary) 0%,
        rgba(245, 245, 247, 0.5) 50%,
        var(--bg-primary) 100%);
    opacity: 0.5;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    position: relative;
    z-index: 1;
}

.project-card {
    padding: var(--spacing-xl);
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    border: 1px solid var(--color-light-gray);
    transition: all var(--transition-base);
}

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.project-icon {
    width: 64px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: var(--radius-md);
    color: white;
    margin-bottom: var(--spacing-lg);
}

.project-icon svg {
    width: 32px;
    height: 32px;
}

.project-title {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: var(--spacing-sm);
}

.project-description {
    font-size: 1rem;
    color: var(--color-gray);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

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

.tag {
    padding: 0.375rem 0.875rem;
    background: var(--color-light-gray);
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-dark-gray);
}

.project-links {
    display: flex;
    gap: var(--spacing-md);
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-accent);
    transition: color var(--transition-fast);
}

.project-link:hover {
    color: var(--color-accent-hover);
}

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

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

@media (max-width: 768px) {
    .about-grid {
        grid-template-columns: 1fr;
    }
}

.about-image {
    display: flex;
    justify-content: center;
}

.avatar-placeholder {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.avatar-placeholder svg {
    width: 100px;
    height: 100px;
}

.about-content .section-title {
    text-align: left;
    margin-bottom: var(--spacing-lg);
}

.about-text {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--color-dark-gray);
    margin-bottom: var(--spacing-md);
}

.skills {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin: var(--spacing-lg) 0;
}

.skill-tag {
    padding: 0.5rem 1rem;
    background: var(--bg-primary);
    border-radius: 980px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-dark-gray);
    border: 1px solid var(--color-light-gray);
    transition: all var(--transition-base);
}

.skill-tag:hover {
    background: var(--color-dark-gray);
    color: var(--color-white);
    border-color: var(--color-dark-gray);
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.social-link {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--bg-primary);
    color: var(--color-dark-gray);
    border: 1px solid var(--color-light-gray);
    transition: all var(--transition-base);
}

.social-link:hover {
    background: var(--color-dark-gray);
    color: var(--color-white);
    transform: translateY(-4px);
}

/* ===================================
   Footer
   =================================== */
.global-footer {
    background: var(--color-light-gray);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-title {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-dark-gray);
    margin-bottom: var(--spacing-md);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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

.footer-links li a {
    font-size: 0.875rem;
    color: var(--color-gray);
    transition: color var(--transition-fast);
}

.footer-links li a:hover {
    color: var(--color-dark-gray);
}

.footer-text {
    font-size: 0.875rem;
    color: var(--color-gray);
    margin-bottom: var(--spacing-sm);
}

.subscribe-form {
    display: flex;
    gap: var(--spacing-sm);
    flex-direction: column;
}

.subscribe-form input {
    padding: 0.75rem 1rem;
    border: 1px solid var(--color-gray);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-family: inherit;
    transition: all var(--transition-base);
}

.subscribe-form input:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

.subscribe-form button {
    padding: 0.75rem 1rem;
    background: var(--color-dark-gray);
    color: var(--color-white);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    transition: all var(--transition-base);
}

.subscribe-form button:hover {
    background: var(--color-black);
    transform: translateY(-2px);
}

.footer-bottom {
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(0, 0, 0, 0.08);
    text-align: center;
}

.footer-bottom p {
    font-size: 0.75rem;
    color: var(--color-gray);
    margin-bottom: 0.25rem;
}

.icp-info {
    margin-top: 0.5rem;
}

.icp-info a {
    color: var(--color-gray);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

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

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

/* Scroll reveal animation */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* Smooth scroll */
html {
    scroll-behavior: smooth;
}

/* Selection */
::selection {
    background: rgba(102, 126, 234, 0.2);
    color: var(--color-dark-gray);
}

/* Focus styles */
a:focus-visible,
button:focus-visible,
input:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* ===================================
   Responsive Adjustments
   =================================== */
@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }

    .hero {
        padding: 100px var(--spacing-md) 40px;
    }

    .hero-actions {
        flex-direction: column;
        width: 100%;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

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

/* Print styles */
@media print {
    .global-nav,
    .hero-scroll,
    .social-links,
    .subscribe-form {
        display: none;
    }

    .article-card,
    .project-card {
        break-inside: avoid;
    }
}