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

:root {
    --primary-color: #1a365d;
    --secondary-color: #2c5282;
    --accent-color: #2f855a;
    --accent-hover: #38a169;
    --text-primary: #1a202c;
    --text-secondary: #2d3748;
    --text-light: #4a5568;
    --bg-primary: #ffffff;
    --bg-secondary: #f7fafc;
    --bg-tertiary: #edf2f7;
    --border-color: #e2e8f0;
    --border-focus: #4299e1;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --radius-lg: 12px;
    --max-width: 1200px;
}

html {
    scroll-padding-top: 140px;

}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    line-height: 1.7;
    color: var(--text-secondary);
    background-color: var(--bg-primary);
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Accessibility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

:focus-visible {
    outline: 3px solid var(--border-focus);
    outline-offset: 2px;
    border-radius: 2px;
}

/* Header & Navigation */
header {
    background-color: var(--bg-primary);
    box-shadow: var(--shadow-md);
    position: static;

    top: 0;
    z-index: 1000;
    width: 100%;
    border-bottom: 2px solid var(--bg-tertiary);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    min-height: 70px;
}

.logo {
    text-decoration: none;
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: 700;
    font-family: 'Inter', sans-serif;
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo:hover,
.logo:focus {
    color: var(--secondary-color);
}

.nav-toggle {
    display: none;
    background: var(--bg-primary);
    border: 2px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.5rem 0.75rem;
    font-size: 1rem;
    cursor: pointer;
    border-radius: var(--radius);
    font-family: 'Inter', sans-serif;
    font-weight: 600;
}

.nav-toggle:hover,
.nav-toggle:focus {
    background-color: var(--bg-secondary);
    border-color: var(--secondary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    flex-wrap: wrap;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.875rem;
    padding: 0.5rem 0;
    transition: color 0.2s ease;
    position: relative;
    font-family: 'Inter', sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent-color);
    transition: width 0.2s ease;
}

.nav-link:hover,
.nav-link:focus {
    color: var(--accent-color);
    outline: none;
}

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

.nav-link.active {
    color: var(--accent-color);
}

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

/* Main Content */
main {
    min-height: calc(100vh - 70px - 250px);
    width: 100%;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 4rem 1.5rem 3rem;
    text-align: center;
}

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

.hero h1 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.2;
    font-family: 'Inter', sans-serif;
    letter-spacing: -0.02em;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.95;
    font-weight: 400;
}

.cta-button {
    display: inline-block;
    background-color: var(--accent-color);
    color: white;
    padding: 0.875rem 2rem;
    text-decoration: none;
    border-radius: var(--radius);
    font-weight: 700;
    font-size: 1rem;
    transition: background-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: var(--shadow-md);
    font-family: 'Inter', sans-serif;
}

.cta-button:hover,
.cta-button:focus {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    outline: none;
}

.cta-button:active {
    transform: translateY(0);
}

/* Container */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

/* Section Styles */
.section {
    margin-bottom: 3rem;
    padding: 2rem;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.section h2 {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-family: 'Inter', sans-serif;
    letter-spacing: -0.01em;
}

.section h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 1.5rem 0 0.75rem;
    font-family: 'Inter', sans-serif;
}

.section p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.section ul,
.section ol {
    color: var(--text-secondary);
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.section li {
    margin-bottom: 0.5rem;
}

.section a {
    color: var(--accent-color);
    text-decoration: underline;
    font-weight: 600;
}

.section a:hover,
.section a:focus {
    color: var(--accent-hover);
    outline: none;
}

/* Calculator Cards Grid */
.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.calculator-card {
    background-color: var(--bg-primary);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    text-decoration: none;
    color: inherit;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.calculator-card:hover,
.calculator-card:focus {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

.calculator-card h3 {
    margin: 0;
    font-size: 1.25rem;
    color: var(--primary-color);
}

.calculator-card p {
    margin: 0;
    color: var(--text-light);
    font-size: 0.875rem;
    flex-grow: 1;
}

.card-icon {
    font-size: 2rem;
    line-height: 1;
}

/* Calculator Page */
.page-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 2.5rem 1.5rem 2rem;
    text-align: center;
}

.page-header-content {
    max-width: 900px;
    margin: 0 auto;
}

.page-header h1 {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 0.75rem;
    font-family: 'Inter', sans-serif;
    letter-spacing: -0.02em;
}

.page-header p {
    font-size: 1rem;
    opacity: 0.95;
}

/* Calculator Layout */
.calculator-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    max-width: var(--max-width);
    margin: 2rem auto;
    padding: 0 1.5rem;
}

.calculator-form-container,
.calculator-results-container {
    background-color: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.calculator-form-container h2,
.calculator-results-container h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1.25rem;
    font-family: 'Inter', sans-serif;
}

/* Form Styles */
.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.form-group input[type="number"],
.form-group input[type="text"],
.form-group select {
    width: 100%;
    padding: 0.625rem 0.75rem;
    font-size: 0.875rem;
    font-family: 'Inter', sans-serif;
    color: var(--text-secondary);
    background-color: var(--bg-primary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-group input[type="number"]:hover,
.form-group input[type="text"]:hover,
.form-group select:hover {
    border-color: var(--secondary-color);
}

.form-group input[type="number"]:focus,
.form-group input[type="text"]:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px rgba(66, 153, 225, 0.3);
}

.form-group small {
    display: block;
    margin-top: 0.375rem;
    font-size: 0.75rem;
    color: var(--text-light);
}

/* Result Display */
.result-item {
    margin-bottom: 0.875rem;
    padding-bottom: 0.875rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.result-item:last-of-type {
    border-bottom: 2px solid var(--border-color);
    margin-bottom: 1rem;
}

.result-label {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.result-value {
    font-weight: 700;
    color: var(--accent-color);
    font-size: 0.875rem;
    text-align: right;
    word-break: break-word;
}

.result-total {
    font-size: 1.25rem !important;
    color: var(--primary-color) !important;
}

/* Ad Slot */
.ad-slot {
    max-width: 728px;
    margin: 2rem auto;
    padding: 2rem;
    background: linear-gradient(135deg, var(--bg-tertiary) 0%, var(--bg-secondary) 100%);
    border: 2px dashed #cbd5e0;
    border-radius: var(--radius-lg);
    text-align: center;
    color: var(--text-light);
    font-weight: 600;
    font-size: 0.875rem;
    font-family: 'Inter', sans-serif;
    min-height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Content Section */
.content-section {
    max-width: var(--max-width);
    margin: 2rem auto;
    padding: 0 1.5rem;
}

/* Info Box */
.info-box {
    background-color: #e6fffa;
    border-left: 4px solid var(--accent-color);
    padding: 1rem 1.25rem;
    margin: 1rem 0;
    border-radius: 0 var(--radius) var(--radius) 0;
    color: var(--text-secondary);
}

/* Footer */
footer {
    background-color: var(--primary-color);
    color: white;
    padding: 2rem 1.5rem 1.5rem;
    margin-top: 3rem;
}

.footer-content {
    max-width: var(--max-width);
    margin: 0 auto;
}

.footer-links {
    display: flex;
    gap: 1.5rem;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 1rem;
    list-style: none;
}

.footer-links a {
    color: white;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.875rem;
    transition: opacity 0.2s ease;
    font-family: 'Inter', sans-serif;
}

.footer-links a:hover,
.footer-links a:focus {
    opacity: 0.8;
    outline: none;
    text-decoration: underline;
}

.footer-bottom {
    text-align: center;
    padding-top: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.9);
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 968px) {
    .calculator-layout {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
}

@media (max-width: 768px) {
    .nav-toggle {
        display: block;
    }

    .nav-menu {
        display: none;
        width: 100%;
        flex-direction: column;
        gap: 0;
        background-color: var(--bg-primary);
        position: absolute;
        top: 70px;
        left: 0;
        box-shadow: var(--shadow-md);
        border-bottom: 2px solid var(--bg-tertiary);
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-menu li {
        width: 100%;
        border-top: 1px solid var(--bg-tertiary);
    }

    .nav-link {
        display: block;
        padding: 0.875rem 1.5rem;
        width: 100%;
    }

    .nav-link::after {
        display: none;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1.125rem;
    }

    .section {
        padding: 1.25rem;
    }

    .container {
        padding: 1.25rem;
    }

    .calculator-layout {
        padding: 0 1rem;
    }

    .ad-slot {
        margin: 1.5rem 1rem;
    }
}

@media (max-width: 480px) {
    .nav-container {
        padding: 0 1rem;
    }

    .hero {
        padding: 3rem 1rem 2rem;
    }

    .hero h1 {
        font-size: 1.75rem;
    }

    .page-header {
        padding: 2rem 1rem 1.5rem;
    }

    .page-header h1 {
        font-size: 1.75rem;
    }

    .section h2 {
        font-size: 1.5rem;
    }

    .calculators-grid {
        grid-template-columns: 1fr;
    }
}
@media (max-width: 600px) {
  .nav-container {
    flex-wrap: nowrap;
    padding: 0 0.75rem;
    gap: 0.5rem;
  }
  .logo {
    font-size: 1.1rem;
    gap: 0.35rem;
  }
  .nav-toggle {
    padding: 0.4rem 0.6rem;
    font-size: 0.9rem;
    white-space: nowrap;
  }
}