/* ============================================
   Ultra Minimal White/Black/Blue Portfolio
   Design Philosophy: Clarity, Space, Precision
   ============================================ */

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

:root {
    /* Core Colors */
    --color-primary: #2E5EFF;        /* Electric Blue */
    --color-primary-dark: #1E40AF;   /* Deep Blue */
    --color-black: #0A0A0A;          /* Almost Black */
    --color-gray-900: #1A1A1A;       /* Charcoal */
    --color-gray-700: #3A3A3A;       /* Dark Gray */
    --color-gray-500: #6A6A6A;       /* Medium Gray */
    --color-gray-300: #AAAAAA;       /* Light Gray */
    --color-gray-100: #F5F7FA;       /* Very Light Gray */
    --color-white: #FFFFFF;          /* Pure White */
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'SF Mono', 'Monaco', 'Cascadia Code', monospace;
    
    /* Spacing System */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-24: 6rem;
    --space-32: 8rem;
    
    /* Layout */
    --max-width: 1200px;
    --max-width-narrow: 800px;
    --nav-height: 80px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    background-color: var(--color-white);
    color: var(--color-gray-900);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ============ Typography ============ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--color-black);
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    letter-spacing: -0.03em;
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    letter-spacing: -0.02em;
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
}

h4 {
    font-size: 1.25rem;
}

p {
    color: var(--color-gray-700);
    line-height: 1.7;
}

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

/* ============ Layout ============ */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-8);
}

.container-narrow {
    max-width: var(--max-width-narrow);
    margin: 0 auto;
    padding: 0 var(--space-8);
}

/* ============ Navigation ============ */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-gray-100);
    transition: all var(--transition-base);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-8);
    height: var(--nav-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-black);
    letter-spacing: -0.02em;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--space-8);
}

.nav-link {
    color: var(--color-gray-700);
    font-size: 0.9rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
}

.nav-link.active::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
}

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

/* ============ Hero Section (Home) ============ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: var(--nav-height);
    padding-bottom: var(--space-24);
}

.hero-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-8);
    text-align: center;
}

.hero-label {
    display: inline-block;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: var(--space-6);
}

.hero-title {
    margin-bottom: var(--space-6);
    line-height: 1.1;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-gray-500);
    margin-bottom: var(--space-12);
    font-weight: 400;
}

.hero-actions {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    margin-bottom: var(--space-16);
}

.hero-scroll {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-2);
    color: var(--color-gray-300);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.scroll-indicator {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, var(--color-gray-300), transparent);
    animation: scroll-fade 2s ease-in-out infinite;
}

@keyframes scroll-fade {
    0%, 100% { opacity: 0.3; transform: translateY(0); }
    50% { opacity: 1; transform: translateY(10px); }
}

/* ============ Buttons ============ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-3) var(--space-6);
    font-size: 0.9rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    border-radius: 4px;
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: var(--font-primary);
}

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

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

.btn-secondary {
    background: transparent;
    color: var(--color-black);
    border-color: var(--color-gray-300);
}

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

.btn-full {
    width: 100%;
}

/* ============ Quick Info Section ============ */
.quick-info {
    padding: var(--space-24) 0;
    background: var(--color-gray-100);
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-8);
}

.info-item {
    text-align: center;
}

.info-item h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-2);
    color: var(--color-black);
}

.info-item p {
    font-size: 0.95rem;
    color: var(--color-gray-500);
}

/* ============ Section Styles ============ */
section {
    padding: var(--space-24) 0;
}

.section-header {
    margin-bottom: var(--space-16);
}

.section-label {
    display: block;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: var(--space-3);
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: var(--space-4);
}

.section-title-sm {
    font-size: 1.75rem;
    margin-bottom: var(--space-8);
    font-weight: 600;
    color: var(--color-black);
}

/* ============ Featured Section ============ */
.featured {
    background: var(--color-white);
}

.featured-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--space-8);
    margin-bottom: var(--space-12);
}

.featured-card {
    position: relative;
    padding: var(--space-8);
    border: 1px solid var(--color-gray-100);
    border-radius: 8px;
    transition: all var(--transition-base);
    display: block;
}

.featured-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-4px);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.05);
}

.featured-label {
    display: inline-block;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    padding: var(--space-1) var(--space-3);
    background: var(--color-primary);
    color: var(--color-white);
    border-radius: 3px;
    margin-bottom: var(--space-4);
    font-weight: 600;
}

.featured-label.completed {
    background: var(--color-gray-700);
}

.featured-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--space-3);
    color: var(--color-black);
}

.featured-card p {
    color: var(--color-gray-500);
    margin-bottom: var(--space-6);
    line-height: 1.6;
}

.featured-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
}

.featured-tech span {
    font-size: 0.8rem;
    padding: var(--space-1) var(--space-3);
    background: var(--color-gray-100);
    color: var(--color-gray-700);
    border-radius: 3px;
    font-weight: 500;
}

.featured-arrow {
    position: absolute;
    bottom: var(--space-8);
    right: var(--space-8);
    font-size: 1.5rem;
    color: var(--color-primary);
    transition: transform var(--transition-base);
}

.featured-card:hover .featured-arrow {
    transform: translateX(5px);
}

.featured-cta {
    text-align: center;
}

.link-arrow {
    color: var(--color-primary);
    font-weight: 600;
    transition: transform var(--transition-base);
    display: inline-block;
}

.link-arrow:hover {
    transform: translateX(5px);
}

/* ============ CTA Section ============ */
.cta {
    background: var(--color-black);
    color: var(--color-white);
    text-align: center;
}

.cta-content h2 {
    color: var(--color-white);
    margin-bottom: var(--space-4);
}

.cta-content p {
    color: var(--color-gray-300);
    font-size: 1.1rem;
    margin-bottom: var(--space-8);
}

/* ============ Footer ============ */
.footer {
    background: var(--color-white);
    border-top: 1px solid var(--color-gray-100);
    padding: var(--space-12) 0;
}

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

.footer-name {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-black);
    margin-bottom: var(--space-1);
}

.footer-role {
    color: var(--color-gray-500);
    font-size: 0.9rem;
}

.footer-social {
    display: flex;
    gap: var(--space-6);
    margin-bottom: var(--space-2);
}

.footer-social a {
    color: var(--color-gray-500);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.footer-social a:hover {
    color: var(--color-primary);
}

.footer-copyright {
    color: var(--color-gray-300);
    font-size: 0.85rem;
}

.footer-right {
    text-align: right;
}

/* ============ Page Header (Subpages) ============ */
.page-header {
    padding-top: calc(var(--nav-height) + var(--space-24));
    padding-bottom: var(--space-16);
    text-align: center;
    border-bottom: 1px solid var(--color-gray-100);
}

.page-label {
    display: block;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: var(--space-4);
}

.page-title {
    font-size: 3.5rem;
    margin-bottom: var(--space-3);
}

.page-subtitle {
    font-size: 1.1rem;
    color: var(--color-gray-500);
}

/* ============ About Page ============ */
.about-content {
    padding: var(--space-24) 0;
}

.about-intro {
    max-width: 800px;
    margin: 0 auto var(--space-24);
    text-align: center;
}

.intro-text {
    font-size: 1.5rem;
    line-height: 1.6;
    color: var(--color-gray-700);
    font-weight: 400;
}

.values-section,
.education-section,
.philosophy-section {
    margin-bottom: var(--space-24);
}

.values-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-8);
}

.value-card {
    padding: var(--space-8);
    border: 1px solid var(--color-gray-100);
    border-radius: 8px;
    transition: all var(--transition-base);
}

.value-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-4px);
}

.value-number {
    font-size: 0.8rem;
    color: var(--color-primary);
    font-weight: 700;
    margin-bottom: var(--space-3);
    font-family: var(--font-mono);
}

.value-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-3);
    color: var(--color-black);
}

.value-card p {
    color: var(--color-gray-500);
    line-height: 1.6;
}

.education-card {
    max-width: 600px;
    margin: 0 auto;
    padding: var(--space-8);
    border: 1px solid var(--color-gray-100);
    border-radius: 8px;
    display: flex;
    gap: var(--space-6);
    align-items: flex-start;
}

.education-period {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-primary);
    font-weight: 600;
    white-space: nowrap;
}

.education-info h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-2);
}

.education-info p {
    color: var(--color-gray-500);
}

.philosophy-content {
    max-width: 800px;
    margin: 0 auto;
}

.philosophy-item {
    padding: var(--space-8);
    border-bottom: 1px solid var(--color-gray-100);
}

.philosophy-item:last-child {
    border-bottom: none;
}

.philosophy-item h4 {
    font-size: 1.25rem;
    margin-bottom: var(--space-3);
    color: var(--color-black);
}

.philosophy-item p {
    color: var(--color-gray-500);
    line-height: 1.7;
}

/* ============ Skills Page ============ */
.skills-content {
    padding: var(--space-16) 0;
}

.skill-category {
    margin-bottom: var(--space-24);
    padding-bottom: var(--space-24);
    border-bottom: 1px solid var(--color-gray-100);
}

.skill-category:last-child {
    border-bottom: none;
}

.skill-category-header {
    margin-bottom: var(--space-12);
}

.skill-category-header h2 {
    font-size: 2rem;
    margin-bottom: var(--space-2);
}

.skill-category-header p {
    font-size: 1.1rem;
    color: var(--color-gray-500);
}

.skill-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--space-6);
}

.skill-item {
    padding: var(--space-6);
    border: 1px solid var(--color-gray-100);
    border-radius: 8px;
    transition: all var(--transition-base);
}

.skill-item:hover {
    border-color: var(--color-primary);
    transform: translateY(-2px);
}

.skill-info h3 {
    font-size: 1.1rem;
    margin-bottom: var(--space-2);
    color: var(--color-black);
}

.skill-info p {
    font-size: 0.9rem;
    color: var(--color-gray-500);
}

.learning-section {
    background: var(--color-gray-100);
    padding: var(--space-24) 0;
}

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

.learning-content h2 {
    margin-bottom: var(--space-6);
}

.learning-content p {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--color-gray-700);
}

/* ============ Projects Page ============ */
.projects-content {
    padding: var(--space-16) 0;
}

.project-detail {
    position: relative;
    margin-bottom: var(--space-24);
    padding: var(--space-12);
    border: 1px solid var(--color-gray-100);
    border-radius: 8px;
    transition: all var(--transition-base);
}

.project-detail:hover {
    border-color: var(--color-primary);
}

.project-status-badge {
    display: inline-block;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    padding: var(--space-2) var(--space-4);
    background: var(--color-primary);
    color: var(--color-white);
    border-radius: 3px;
    margin-bottom: var(--space-6);
    font-weight: 600;
}

.project-status-badge.completed {
    background: var(--color-gray-700);
}

.project-status-badge.ongoing {
    background: var(--color-primary);
}

.project-main h2 {
    font-size: 2rem;
    margin-bottom: var(--space-2);
}

.project-tagline {
    font-size: 1.1rem;
    color: var(--color-gray-500);
    margin-bottom: var(--space-8);
}

.project-description {
    margin-bottom: var(--space-8);
}

.project-description p {
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--color-gray-700);
}

.project-tech-stack,
.project-highlights {
    margin-bottom: var(--space-8);
}

.project-tech-stack h3,
.project-highlights h3 {
    font-size: 1.1rem;
    margin-bottom: var(--space-4);
    color: var(--color-black);
}

.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
}

.tech-tag {
    font-size: 0.85rem;
    padding: var(--space-2) var(--space-4);
    background: var(--color-gray-100);
    color: var(--color-gray-700);
    border-radius: 3px;
    font-weight: 500;
}

.project-highlights ul {
    list-style: none;
    padding: 0;
}

.project-highlights li {
    padding-left: var(--space-6);
    position: relative;
    margin-bottom: var(--space-3);
    color: var(--color-gray-700);
}

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

/* ============ Contact Page ============ */
.contact-content {
    padding: var(--space-16) 0;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-16);
}

.contact-info-section h2 {
    font-size: 2.5rem;
    margin-bottom: var(--space-6);
}

.contact-intro {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--color-gray-700);
    margin-bottom: var(--space-12);
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: var(--space-8);
}

.contact-method h3 {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-gray-500);
    margin-bottom: var(--space-2);
    font-weight: 600;
}

.contact-link {
    font-size: 1.1rem;
    color: var(--color-primary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.contact-link:hover {
    color: var(--color-primary-dark);
}

.contact-form-section {
    background: var(--color-gray-100);
    padding: var(--space-8);
    border-radius: 8px;
}

.contact-form {
    margin-bottom: var(--space-6);
}

.form-group {
    margin-bottom: var(--space-6);
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-gray-700);
    margin-bottom: var(--space-2);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    font-size: 1rem;
    font-family: var(--font-primary);
    border: 1px solid var(--color-gray-300);
    border-radius: 4px;
    background: var(--color-white);
    color: var(--color-gray-900);
    transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

.form-group textarea {
    resize: vertical;
    min-height: 150px;
}

.form-notice {
    padding: var(--space-4);
    background: rgba(46, 94, 255, 0.05);
    border-left: 3px solid var(--color-primary);
    border-radius: 4px;
}

.form-notice p {
    font-size: 0.9rem;
    color: var(--color-gray-700);
}

.form-notice strong {
    color: var(--color-black);
}

.availability-section {
    background: var(--color-gray-100);
    padding: var(--space-16) 0;
}

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

.availability-content h2 {
    margin-bottom: var(--space-6);
}

.availability-status {
    display: inline-flex;
    align-items: center;
    gap: var(--space-3);
    margin-bottom: var(--space-6);
    padding: var(--space-3) var(--space-6);
    background: var(--color-white);
    border-radius: 50px;
    font-weight: 600;
}

.status-indicator {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #10B981;
    animation: pulse 2s ease-in-out infinite;
}

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

.availability-content p {
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--color-gray-700);
}

/* ============ Responsive Design ============ */
@media (max-width: 768px) {
    :root {
        --nav-height: 70px;
        --space-24: 4rem;
        --space-32: 6rem;
    }
    
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: var(--space-6);
        gap: var(--space-4);
        border-bottom: 1px solid var(--color-gray-100);
    }
    
    .nav-menu.active {
        display: flex;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-actions {
        flex-direction: column;
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
    
    .featured-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
        gap: var(--space-6);
    }
    
    .footer-right {
        text-align: center;
    }
    
    .page-title {
        font-size: 2.5rem;
    }
    
    .values-grid {
        grid-template-columns: 1fr;
    }
    
    .skill-list {
        grid-template-columns: 1fr;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
    }
    
    .project-detail {
        padding: var(--space-6);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-4);
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .page-title {
        font-size: 2rem;
    }
}