/* CSS Variables */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #0ea5e9;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --dark: #1e293b;
    --dark-light: #334155;
    --light: #f8fafc;
    --gray: #64748b;
    --gray-light: #e2e8f0;
    --gradient: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --radius: 12px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background-color: var(--light);
    color: var(--dark);
    line-height: 1.6;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
    box-shadow: var(--shadow);
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 0.5rem;
}

.nav-link {
    text-decoration: none;
    color: var(--dark);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: var(--transition);
    font-weight: 500;
}

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

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    text-align: center;
    padding: 2rem;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.1'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 700px;
}

.hero h1 {
    font-size: 3.5rem;
    color: white;
    margin-bottom: 1.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.hero p {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 2rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

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

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

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

.btn-secondary:hover {
    background: var(--gray);
    color: white;
}

.btn-large {
    padding: 1rem 2.5rem;
    font-size: 1.125rem;
}

/* Sections */
.section {
    padding: 5rem 2rem;
}

.section-alt {
    background: linear-gradient(180deg, var(--gray-light) 0%, var(--light) 100%);
}

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

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--dark);
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--gradient);
    border-radius: 2px;
}

/* Card Grid */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

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

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.card h3 {
    color: var(--primary);
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
}

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

/* Info Box */
.info-box {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    border-left: 4px solid var(--primary);
    box-shadow: var(--shadow);
}

.info-box h3 {
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.stages-list {
    padding-left: 1.5rem;
}

.stages-list li {
    margin-bottom: 0.75rem;
    color: var(--dark-light);
}

.stages-list li strong {
    color: var(--dark);
}

/* Strategy Grid */
.strategy-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.strategy-card {
    background: white;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

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

.strategy-header {
    padding: 1.5rem;
    color: white;
}

.strategy-header.win-win {
    background: linear-gradient(135deg, var(--success) 0%, #059669 100%);
}

.strategy-header.distributive {
    background: linear-gradient(135deg, var(--warning) 0%, #d97706 100%);
}

.strategy-header.principled {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
}

.strategy-header h3 {
    margin: 0;
    font-size: 1.25rem;
}

.strategy-body {
    padding: 1.5rem;
}

.strategy-body p {
    color: var(--gray);
    margin-bottom: 1rem;
}

.strategy-body ul {
    list-style: none;
    margin-bottom: 1rem;
}

.strategy-body li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--dark-light);
}

.strategy-body li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success);
    font-weight: bold;
}

/* Badges */
.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success);
}

.badge-warning {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning);
}

.badge-info {
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary);
}

/* Tactics */
.tactics-container {
    max-width: 800px;
    margin: 0 auto 3rem;
}

.tactic-item {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    padding: 1.5rem;
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.tactic-item:hover {
    transform: translateX(10px);
    box-shadow: var(--shadow-lg);
}

.tactic-number {
    width: 50px;
    height: 50px;
    background: var(--gradient);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    font-weight: bold;
    flex-shrink: 0;
}

.tactic-content h4 {
    color: var(--dark);
    margin-bottom: 0.5rem;
}

.tactic-content p {
    color: var(--gray);
}

/* Warning Box */
.warning-box {
    background: white;
    border-radius: var(--radius);
    padding: 2rem;
    border-left: 4px solid var(--warning);
    box-shadow: var(--shadow);
}

.warning-box h4 {
    color: var(--warning);
    margin-bottom: 1.5rem;
    font-size: 1.25rem;
}

.counter-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
}

.counter-item {
    padding: 1rem;
    background: var(--light);
    border-radius: 8px;
    color: var(--dark-light);
}

.counter-item strong {
    color: var(--dark);
}

/* Quiz Styles */
#quiz-container {
    max-width: 700px;
    margin: 0 auto;
}

#quiz-intro {
    text-align: center;
    background: white;
    padding: 3rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.quiz-description {
    font-size: 1.125rem;
    color: var(--gray);
    margin-bottom: 2rem;
}

.quiz-progress {
    margin-bottom: 2rem;
}

.progress-bar {
    height: 8px;
    background: var(--gray-light);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: var(--gradient);
    transition: width 0.3s ease;
    border-radius: 4px;
}

#progress-text {
    color: var(--gray);
    font-size: 0.875rem;
}

#question-container {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 1.5rem;
}

#question-text {
    color: var(--dark);
    margin-bottom: 1.5rem;
    font-size: 1.25rem;
    line-height: 1.5;
}

#options-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.option-btn {
    padding: 1rem 1.5rem;
    background: var(--light);
    border: 2px solid var(--gray-light);
    border-radius: 8px;
    cursor: pointer;
    text-align: left;
    font-size: 1rem;
    color: var(--dark);
    transition: var(--transition);
}

.option-btn:hover:not(:disabled) {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.05);
}

.option-btn.selected {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.1);
}

.option-btn.correct {
    border-color: var(--success);
    background: rgba(16, 185, 129, 0.1);
    color: var(--success);
}

.option-btn.incorrect {
    border-color: var(--danger);
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
}

.option-btn:disabled {
    cursor: default;
}

#feedback {
    background: white;
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
}

#feedback-content {
    margin-bottom: 1rem;
    font-size: 1rem;
    line-height: 1.6;
}

#feedback-content.correct {
    color: var(--success);
}

#feedback-content.incorrect {
    color: var(--danger);
}

/* Quiz Results */
.results-card {
    background: white;
    padding: 3rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
}

#score-circle {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: var(--gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 2rem;
}

#score-text {
    font-size: 2.5rem;
    font-weight: bold;
    color: white;
}

#results-message {
    font-size: 1.5rem;
    color: var(--dark);
    margin-bottom: 1rem;
}

#results-detail {
    color: var(--gray);
    margin-bottom: 2rem;
}

.results-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

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

.results-actions .btn-primary:hover {
    background: var(--primary-dark);
}

/* Footer */
.footer {
    background: var(--dark);
    color: var(--gray-light);
    text-align: center;
    padding: 2rem;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Responsive Design */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }

    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .section {
        padding: 3rem 1rem;
    }

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

    .tactic-item {
        flex-direction: column;
        text-align: center;
    }

    .tactic-number {
        margin: 0 auto;
    }

    .results-actions {
        flex-direction: column;
    }
}