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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #f59e0b;
    --accent-color: #10b981;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --background: #ffffff;
    --background-light: #f9fafb;
    --background-dark: #f3f4f6;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
    scroll-behavior: smooth;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--primary-color);
}

.nav-logo i {
    font-size: 1.5rem;
}

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

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

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

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--background-light) 0%, var(--background) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="%23e5e7eb" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.5;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.6;
}

.hero-meta {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.author-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.author-avatar i {
    font-size: 3rem;
    color: var(--primary-color);
}

.author-details {
    display: flex;
    flex-direction: column;
}

.author-name {
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.author-title {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.publication-info {
    display: flex;
    gap: 1rem;
    font-size: 0.9rem;
    color: var(--text-light);
}

.hero-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.tag {
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* Design Thinking Circle */
.design-thinking-circle {
    position: relative;
    width: 400px;
    height: 400px;
    margin: 0 auto;
}

.circle-step {
    position: absolute;
    width: 80px;
    height: 80px;
    background: white;
    border: 3px solid var(--primary-color);
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--primary-color);
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    cursor: pointer;
}

.circle-step:hover {
    transform: scale(1.1);
    background: var(--primary-color);
    color: white;
}

.circle-step i {
    font-size: 1.5rem;
    margin-bottom: 0.25rem;
}

.circle-step[data-step="1"] { top: 0; left: 50%; transform: translateX(-50%); }
.circle-step[data-step="2"] { top: 25%; right: 0; }
.circle-step[data-step="3"] { bottom: 25%; right: 0; }
.circle-step[data-step="4"] { bottom: 0; left: 50%; transform: translateX(-50%); }
.circle-step[data-step="5"] { top: 25%; left: 0; }

/* Section Styles */
.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: var(--primary-color);
    border-radius: 2px;
}

/* Challenge Section */
.challenge {
    padding: 80px 0;
    background: var(--background);
}

.lead {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    text-align: center;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.challenge-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.challenge-item {
    display: flex;
    gap: 1.5rem;
    padding: 2rem;
    background: var(--background-light);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.challenge-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.challenge-icon {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.challenge-info h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.challenge-info p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Process Section */
.process {
    padding: 80px 0;
    background: var(--background-light);
}

.process-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.process-timeline::before {
    content: '';
    position: absolute;
    left: 30px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--primary-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    padding-left: 80px;
}

.timeline-marker {
    position: absolute;
    left: 0;
    top: 0;
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    box-shadow: var(--shadow-md);
    z-index: 1;
}

.timeline-content {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.timeline-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.timeline-content p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.resources {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.resource-tag {
    background: var(--secondary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
}

.timeline-duration {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent-color);
    font-weight: 500;
    margin-top: 1rem;
}

/* Results Section */
.results {
    padding: 80px 0;
    background: var(--background);
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.result-card {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-color);
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.result-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
}

.result-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.result-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin: 0 auto 1.5rem;
}

.result-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.result-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.implementation-note {
    background: linear-gradient(135deg, var(--accent-color), #059669);
    color: white;
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
}

.note-icon {
    flex-shrink: 0;
    font-size: 2rem;
    opacity: 0.8;
}

.note-content h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.note-content p {
    line-height: 1.6;
    opacity: 0.9;
}

/* Takeaways Section */
.takeaways {
    padding: 80px 0;
    background: var(--background-light);
}

.takeaway-highlight {
    text-align: center;
    margin-bottom: 3rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.takeaway-highlight i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.takeaway-highlight blockquote {
    font-size: 1.5rem;
    font-style: italic;
    color: var(--text-primary);
    margin-bottom: 1rem;
    line-height: 1.4;
}

.takeaway-highlight cite {
    font-size: 1.1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.key-ingredients h3 {
    font-size: 1.5rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.ingredients-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.ingredient {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.ingredient:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.ingredient i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.ingredient span {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* References Section */
.references {
    padding: 60px 0;
    background: var(--background);
}

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

.reference-item {
    display: flex;
    gap: 1rem;
    padding: 1.5rem;
    background: var(--background-light);
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    border-left: 4px solid var(--primary-color);
}

.reference-item i {
    color: var(--primary-color);
    font-size: 1.2rem;
    margin-top: 0.2rem;
    flex-shrink: 0;
}

.reference-text {
    line-height: 1.6;
    color: var(--text-secondary);
}

.reference-text a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.reference-text a:hover {
    text-decoration: underline;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 60px 0 40px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
}

.author-section h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: white;
}

.author-section p {
    line-height: 1.6;
    color: #d1d5db;
    margin-bottom: 1.5rem;
}

.author-links {
    display: flex;
    gap: 1rem;
}

.social-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #d1d5db;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border: 1px solid #374151;
    border-radius: var(--border-radius);
    transition: var(--transition);
}

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

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

.footer-info p {
    color: #9ca3af;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .design-thinking-circle {
        width: 300px;
        height: 300px;
    }
    
    .circle-step {
        width: 60px;
        height: 60px;
        font-size: 0.7rem;
    }
    
    .circle-step i {
        font-size: 1.2rem;
    }
    
    .challenge-details {
        grid-template-columns: 1fr;
    }
    
    .results-grid {
        grid-template-columns: 1fr;
    }
    
    .ingredients-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-info {
        text-align: center;
    }
    
    .timeline-item {
        padding-left: 60px;
    }
    
    .timeline-marker {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
    
    .process-timeline::before {
        left: 20px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }
    
    .nav-container {
        padding: 0 1rem;
    }
    
    .hero {
        padding: 100px 0 60px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .ingredients-grid {
        grid-template-columns: 1fr;
    }
}

/* Animation Classes */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease-out;
}

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

.slide-in-left {
    opacity: 0;
    transform: translateX(-50px);
    transition: all 0.6s ease-out;
}

.slide-in-left.visible {
    opacity: 1;
    transform: translateX(0);
}

.slide-in-right {
    opacity: 0;
    transform: translateX(50px);
    transition: all 0.6s ease-out;
}

.slide-in-right.visible {
    opacity: 1;
    transform: translateX(0);
}