/* Global Styles */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #333;
    --background-color: #f5f6fa;
    --card-background: #ffffff;
    --border-radius: 8px;
    --box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    margin: 0;
    padding: 0;
}

header {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-bottom: 2rem;
}

header h1 {
    margin: 0;
    font-size: 2.5rem;
}

header p {
    margin: 0.5rem 0 0;
    font-size: 1.2rem;
    opacity: 0.9;
}

main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Card Section Styles */
.card-section {
    margin-bottom: 2rem;
    background: var(--card-background);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
}

/* Introduction Cards */
.introduction {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.intro-card {
    padding: 1.5rem;
    background: var(--card-background);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.feature-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.feature-list li {
    display: flex;
    align-items: center;
    margin-bottom: 0.8rem;
}

.feature-list i {
    margin-right: 0.8rem;
    color: var(--secondary-color);
}

/* Calculator Form Styles */
.calculator-container {
    display: grid;
    grid-template-columns: 7fr 3fr;
    gap: 2rem;
}

.calculator-container form {
    max-width: 600px;
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

input, select {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
}

.calculate-btn {
    background-color: var(--secondary-color);
    color: white;
    padding: 1rem 2rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1.1rem;
    transition: background-color 0.3s;
}

.calculate-btn:hover {
    background-color: #2980b9;
}

/* Results Styles */
.results {
    background: var(--card-background);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.result-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
    padding: 0.5rem 0;
    border-bottom: 1px solid #eee;
}

/* Formula Section Styles */
.formula-card {
    background: var(--card-background);
    padding: 2rem;
    border-radius: var(--border-radius);
}

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

.formula-list li {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
    position: relative;
}

.formula-list li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
}

/* FAQ Accordion Styles */
.accordion-item {
    margin-bottom: 1rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
}

.accordion-header {
    margin: 0;
    padding: 1rem;
    background-color: #f8f9fa;
    cursor: pointer;
    position: relative;
}

.accordion-header::after {
    content: '+';
    position: absolute;
    right: 1rem;
    transition: transform 0.3s;
}

.accordion-item.active .accordion-header::after {
    transform: rotate(45deg);
}

.accordion-content {
    padding: 0 1rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
}

.accordion-item.active .accordion-content {
    max-height: 200px;
    padding: 1rem;
}

.accordion-item.active .accordion-content {
    padding: 1rem;
    max-height: 500px;
}

/* Related Tools Grid */
.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.calculator-card {
    display: block;
    text-decoration: none;
    color: var(--text-color);
    background: var(--card-background);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    transition: transform 0.3s;
}

.calculator-card:hover {
    transform: translateY(-5px);
}

.calculator-card i {
    font-size: 2rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
    display: block;
}

/* Footer Styles */
footer {
    text-align: center;
    padding: 2rem;
    background-color: var(--primary-color);
    color: white;
    margin-top: 3rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .calculator-container {
        grid-template-columns: 1fr;
    }

    .introduction {
        grid-template-columns: 1fr;
    }

    .calculator-grid {
        grid-template-columns: 1fr;
    }

    header h1 {
        font-size: 2rem;
    }

    header p {
        font-size: 1rem;
    }
}