/* ==========================================================================
   CSS PORTFOLIO - KAI BOOMGAARDEN
   Designed with a highly professional, modern dark tech theme (Emerald & Slate)
   ========================================================================== */

/* Variables / Theme Configuration */
:root {
    --primary: #10b981;          /* Emerald Green - represents growth, tech, action */
    --primary-hover: #059669;
    --primary-light: rgba(16, 185, 129, 0.1);
    
    --bg-dark: #090d16;          /* Deepest space blue-grey */
    --bg-surface: #111827;       /* Surface card background */
    --bg-surface-hover: #1f2937; /* Hovered surface background */
    --bg-light: #0d1424;         /* Section alternative background */
    
    --text-main: #f3f4f6;        /* Primary high-contrast text */
    --text-muted: #9ca3af;       /* Secondary descriptive text */
    --text-dark: #6b7280;        /* Deep grey placeholder text */
    
    --border-color: #1f2937;     /* High-quality subtle dark borders */
    --border-accent: rgba(16, 185, 129, 0.3);
    
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    
    --container-max-width: 1200px;
    --header-height: 80px;
}

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

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

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-sans);
    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: 700;
    line-height: 1.25;
    color: #ffffff;
}

p {
    color: var(--text-muted);
    font-weight: 400;
}

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

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

/* Layout Utilities */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section-padding {
    padding: 6.5rem 0;
}

.bg-light {
    background-color: var(--bg-light);
}

.highlight {
    color: var(--primary);
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 0.95rem;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition-fast);
    border: none;
}

.btn-primary {
    background-color: var(--primary);
    color: #030712;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.25);
}

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

.btn-secondary:hover {
    background-color: var(--bg-surface-hover);
    border-color: var(--text-muted);
    transform: translateY(-2px);
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
}

.btn-block {
    display: flex;
    width: 100%;
}

/* Badges & Section Headers */
.badge {
    display: inline-block;
    background-color: var(--primary-light);
    color: var(--primary);
    font-size: 0.85rem;
    font-weight: 600;
    padding: 0.4rem 1rem;
    border-radius: 50px;
    border: 1px solid var(--border-accent);
    margin-bottom: 1.5rem;
}

.section-header {
    text-align: center;
    margin-bottom: 4.5rem;
}

.section-subtitle {
    display: block;
    color: var(--primary);
    font-size: 0.9rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 0.5rem;
}

.section-header h2 {
    font-size: 2.25rem;
    margin-bottom: 1rem;
}

.underline {
    width: 60px;
    height: 4px;
    background-color: var(--primary);
    margin: 0 auto;
    border-radius: 2px;
}

.section-intro {
    max-width: 600px;
    margin: 1rem auto 0 auto;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background-color: rgba(9, 13, 22, 0.9);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    display: flex;
    align-items: center;
    transition: var(--transition-normal);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: #ffffff;
    letter-spacing: -0.02em;
}

.logo span {
    color: var(--primary);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2.5rem;
}

.nav-links a {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-muted);
}

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

.nav-cta {
    margin-left: 1rem;
    color: #030712 !important; /* Force readable dark text on emerald background */
}

.nav-cta:hover {
    color: #030712 !important;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: #ffffff;
    font-size: 1.5rem;
    cursor: pointer;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: var(--header-height);
    background-image: radial-gradient(circle at 10% 20%, rgba(16, 185, 129, 0.05) 0%, transparent 40%);
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-size: 3.5rem;
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin-bottom: 1.5rem;
}

.hero-lead {
    font-size: 1.15rem;
    line-height: 1.7;
    margin-bottom: 2.5rem;
}

.hero-actions {
    display: flex;
    gap: 1rem;
}

/* Photo Frame & Profile Image */
.hero-image-container {
    display: flex;
    justify-content: center;
}

.photo-frame {
    position: relative;
    width: 320px;
    height: 320px;
}

.profile-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 12px;
    border: 2px solid var(--border-color);
    position: relative;
    z-index: 2;
}

.frame-accent {
    position: absolute;
    top: 15px;
    left: 15px;
    width: 100%;
    height: 100%;
    border: 2px solid var(--primary);
    border-radius: 12px;
    z-index: 1;
    transition: var(--transition-normal);
}

.photo-frame:hover .frame-accent {
    transform: translate(-10px, -10px);
}

/* ==========================================================================
   About Me Section
   ========================================================================== */
.about-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 4rem;
    align-items: start;
}

.about-text p {
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
    line-height: 1.75;
}

.about-highlights {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.highlight-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 2rem;
    transition: var(--transition-normal);
}

.highlight-card:hover {
    border-color: var(--border-accent);
    transform: translateY(-3px);
}

.highlight-card i {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 1.25rem;
}

.highlight-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

/* ==========================================================================
   Skills Section
   ========================================================================== */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.skills-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2.5rem 2rem;
    transition: var(--transition-normal);
}

.skills-card:hover {
    border-color: var(--border-accent);
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

.skills-icon {
    width: 60px;
    height: 60px;
    background-color: var(--primary-light);
    color: var(--primary);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    margin-bottom: 1.75rem;
    border: 1px solid var(--border-accent);
}

.skills-card h3 {
    font-size: 1.35rem;
    margin-bottom: 0.75rem;
}

.skills-card p {
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
}

.skills-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
}

.skills-list li {
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.skills-list li::before {
    content: "✓";
    color: var(--primary);
    font-weight: 700;
}

/* ==========================================================================
   Projects Section
   ========================================================================== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.project-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    height: 100%;
    transition: var(--transition-normal);
}

.project-card:hover {
    border-color: var(--border-accent);
    transform: translateY(-5px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.2);
}

.project-content {
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.25rem;
}

.tag {
    background-color: var(--bg-surface-hover);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.75rem;
    font-weight: 600;
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
}

.project-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.project-desc {
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.project-features {
    background-color: var(--bg-light);
    border-left: 3px solid var(--primary);
    padding: 1rem;
    border-radius: 0 6px 6px 0;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.project-features strong {
    color: var(--text-main);
    display: block;
    margin-bottom: 0.25rem;
}

.project-links {
    margin-top: auto;
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--primary);
}

.project-link:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

.project-link-inactive {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--text-dark);
}

/* ==========================================================================
   Timeline / Kursplan Section
   ========================================================================== */
.timeline-section {
    position: relative;
}

.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 0;
}

/* Vertical timeline line */
.timeline::after {
    content: '';
    position: absolute;
    width: 2px;
    background-color: var(--border-color);
    top: 0;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
}

.timeline-item {
    padding: 1rem 3rem;
    position: relative;
    width: 50%;
    opacity: 0.9;
}

/* Circular markers */
.timeline-item::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    right: -8px;
    background-color: var(--bg-dark);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    top: 2rem;
    z-index: 1;
    transition: var(--transition-normal);
}

.timeline-item.right::after {
    left: -8px;
}

/* Alignment left & right */
.timeline-item.left {
    left: 0;
    text-align: right;
}

.timeline-item.right {
    left: 50%;
}

/* Card Styling */
.timeline-content {
    padding: 2rem;
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    position: relative;
    transition: var(--transition-normal);
}

.timeline-content:hover {
    border-color: var(--border-accent);
}

.timeline-date {
    display: inline-block;
    color: var(--primary);
    font-weight: 700;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.timeline-content h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.timeline-content p {
    font-size: 0.95rem;
}

/* Timeline badges inside cards */
.timeline-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    margin-top: 1.25rem;
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-dark);
}

/* States */
/* 1. Completed */
.timeline-item.completed::after {
    background-color: var(--primary);
    border-color: var(--primary);
}

.timeline-item.completed .timeline-badge {
    color: var(--primary);
}

/* 2. In Progress */
.timeline-item.in-progress::after {
    background-color: #f59e0b; /* Yellow warning */
    border-color: #f59e0b;
}

.timeline-item.in-progress .timeline-content {
    border-color: rgba(245, 158, 11, 0.4);
    box-shadow: 0 0 15px rgba(245, 158, 11, 0.05);
}

.timeline-item.in-progress .timeline-badge.active {
    color: #f59e0b;
}

/* 3. Highlighted Praktikum (Target) */
.timeline-item.highlight-prak::after {
    background-color: #3b82f6; /* Beautiful Blue accent */
    border-color: #3b82f6;
    transform: scale(1.3);
}

.timeline-item.highlight-prak.left::after {
    right: -10px;
    transform: translateX(0) scale(1.3);
}

.timeline-item.highlight-prak .timeline-content {
    border-color: rgba(59, 130, 246, 0.5);
    background-image: linear-gradient(135deg, rgba(59, 130, 246, 0.05) 0%, transparent 100%);
    box-shadow: 0 10px 25px rgba(59, 130, 246, 0.1);
}

.timeline-item.highlight-prak .timeline-badge.target {
    color: #3b82f6;
    background-color: rgba(59, 130, 246, 0.1);
    padding: 0.3rem 0.8rem;
    border-radius: 4px;
    border: 1px solid rgba(59, 130, 246, 0.2);
}

/* 4. Planned */
.timeline-item.planned {
    opacity: 0.6;
}

/* ==========================================================================
   Contact Section
   ========================================================================== */
.contact-grid {
    display: grid;
    grid-template-columns: 0.9fr 1.1fr;
    gap: 4rem;
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.contact-info-item {
    display: flex;
    gap: 1.5rem;
    align-items: start;
}

.contact-info-item i {
    font-size: 1.5rem;
    color: var(--primary);
    width: 48px;
    height: 48px;
    background-color: var(--primary-light);
    border: 1px solid var(--border-accent);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.contact-info-item h3 {
    font-size: 1.15rem;
    margin-bottom: 0.25rem;
}

.contact-info-item p {
    font-size: 0.95rem;
}

.contact-info-item a:hover {
    color: var(--primary);
    text-decoration: underline;
}

.contact-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 3rem;
}

.contact-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.contact-card p {
    font-size: 1rem;
    margin-bottom: 2rem;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
    background-color: #05080e;
    border-top: 1px solid var(--border-color);
    padding: 3rem 0;
    color: var(--text-dark);
}

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

.footer-content p {
    font-size: 0.9rem;
    color: var(--text-dark);
}

.footer-links {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.footer-links a {
    font-size: 0.9rem;
    color: var(--text-dark);
}

.footer-links a:hover {
    color: var(--text-muted);
}

.footer-links a[aria-label="GitHub"] {
    font-size: 1.5rem;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

@media (max-width: 1024px) {
    .skills-grid, .projects-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    html {
        font-size: 15px;
    }
    
    .section-padding {
        padding: 4.5rem 0;
    }
    
    /* Navigation */
    .mobile-menu-toggle {
        display: block;
    }
    
    .nav-links {
        position: fixed;
        top: var(--header-height);
        left: -100%;
        width: 100%;
        height: calc(100vh - var(--header-height));
        background-color: var(--bg-dark);
        border-top: 1px solid var(--border-color);
        flex-direction: column;
        padding: 3rem 1.5rem;
        gap: 2rem;
        align-items: stretch;
        transition: var(--transition-normal);
        z-index: 999;
    }
    
    .nav-links.active {
        left: 0;
    }
    
    .nav-cta {
        margin-left: 0;
        text-align: center;
    }
    
    /* Hero */
    .hero-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
        padding: 4rem 0;
    }
    
    .hero-content h1 {
        font-size: 2.75rem;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    /* About */
    .about-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }
    
    /* Skills & Projects */
    .skills-grid, .projects-grid {
        grid-template-columns: 1fr;
    }
    
    /* Timeline */
    .timeline::after {
        left: 31px;
    }
    
    .timeline-item {
        width: 100%;
        padding-left: 55px;
        padding-right: 0;
    }
    
    .timeline-item.left {
        text-align: left;
    }
    
    .timeline-item.right {
        left: 0;
    }
    
    .timeline-item::after {
        left: 23px !important;
        right: auto !important;
    }
    
    /* Contact */
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 1.5rem;
        text-align: center;
    }
}