/* VIX Index Replication - Dashboard Styles */

:root {
    --primary: #1f77b4;
    --primary-dark: #1a5a8a;
    --secondary: #ff7f0e;
    --success: #2ca02c;
    --danger: #d62728;
    --purple: #9467bd;
    --dark: #0f172a;
    --light: #f8fafc;
    --gray: #64748b;
    --border: #e2e8f0;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

/* Navigation */
.navbar {
    background: var(--dark);
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-brand h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--dark) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 6rem 2rem;
    text-align: center;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.25rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 2rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.btn {
    padding: 0.875rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
    border: none;
    cursor: pointer;
}

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

.btn-primary:hover {
    background: #e66a00;
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
}

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

.section-alt {
    background: white;
}

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

.section h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    text-align: center;
    color: var(--dark);
}

/* Feature Grid */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border);
}

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

.feature-card p {
    color: var(--gray);
}

/* Methodology Section */
.methodology-content {
    max-width: 900px;
    margin: 0 auto;
}

.methodology-content h3 {
    color: var(--dark);
    margin: 2rem 0 1rem;
}

.formula-box {
    background: var(--light);
    border-left: 4px solid var(--primary);
    padding: 1.5rem 2rem;
    margin: 1.5rem 0;
    border-radius: 0 8px 8px 0;
    overflow-x: auto;
}

.formula-explanation {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.formula-explanation ul {
    list-style: none;
    padding-left: 0;
}

.formula-explanation li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border);
}

.formula-explanation li:last-child {
    border-bottom: none;
}

/* Steps Grid */
.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.step {
    text-align: center;
    padding: 1.5rem;
    background: var(--light);
    border-radius: 12px;
}

.step-number {
    width: 40px;
    height: 40px;
    background: var(--primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    font-weight: 700;
}

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

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

/* Chart Gallery */
.chart-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.chart-item {
    background: white;
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    text-align: center;
}

.chart-item h4 {
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.chart-item p {
    font-size: 0.9rem;
    color: var(--gray);
}

/* References */
.references-list {
    list-style: none;
    max-width: 800px;
    margin: 0 auto;
}

.references-list li {
    padding: 1rem;
    background: var(--light);
    margin-bottom: 1rem;
    border-radius: 8px;
    border-left: 3px solid var(--primary);
}

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

footer p {
    margin: 0.25rem 0;
    opacity: 0.8;
}

/* Calculator Page Specific */
.calculator-container {
    max-width: 1000px;
    margin: 2rem auto;
    padding: 0 2rem;
}

.input-section {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    margin-bottom: 2rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--dark);
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(31, 119, 180, 0.1);
}

.results-section {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.vix-result {
    text-align: center;
    padding: 2rem;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    border-radius: 12px;
    margin-bottom: 2rem;
}

.vix-result .vix-value {
    font-size: 4rem;
    font-weight: 700;
}

.vix-result .vix-label {
    font-size: 1.25rem;
    opacity: 0.9;
}

.step-results {
    display: grid;
    gap: 1rem;
}

.step-result {
    padding: 1rem;
    background: var(--light);
    border-radius: 8px;
    border-left: 3px solid var(--primary);
}

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

.step-result p {
    color: var(--gray);
    font-family: 'Consolas', monospace;
}

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

    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 1rem;
    }

    .hero h2 {
        font-size: 1.75rem;
    }

    .hero-buttons {
        flex-direction: column;
    }

    .steps-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}