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

:root {
    --primary-color: #003366;
    --accent-color: #2d5016;
    --text-color: #333;
    --bg-color: #f5f5f5;
    --white: #ffffff;
    --border-color: #ddd;
    --shadow: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-hover: 0 4px 8px rgba(0,0,0,0.15);
}

/* Accessibility: Visually hidden but accessible to screen readers */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.site-header {
    background-color: var(--primary-color);
    color: var(--white);
    padding: 1rem 0;
    box-shadow: var(--shadow);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.site-logo a {
    color: var(--white);
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: 600;
    display: inline-block;
    line-height: 1;
}

.site-logo img {
    height: 54px;
    width: auto;
    display: block;
}

.language-switcher {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.language-switcher label:not(.visually-hidden) {
    color: var(--white);
    font-size: 0.9rem;
}

.language-switcher select {
    padding: 0.4rem 0.8rem;
    border: none;
    border-radius: 4px;
    background-color: var(--white);
    color: var(--primary-color);
    font-size: 0.9rem;
    cursor: pointer;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 1001;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--white);
    border-radius: 4px;
    transition: all 0.3s ease;
}

.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

/* Main Navigation */
.main-nav {
    display: flex;
    align-items: center;
    gap: 2rem;
    flex: 1;
    justify-content: center;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0.5rem;
    align-items: center;
    margin: 0;
    padding: 0;
}

.nav-item {
    position: relative;
}

.nav-item > a {
    color: var(--white);
    text-decoration: none;
    padding: 0.6rem 1rem;
    display: block;
    border-radius: 4px;
    transition: background-color 0.3s ease;
    font-size: 0.95rem;
}

.nav-item > a:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

/* Dropdown Styles */
.has-dropdown {
    position: relative;
}

.dropdown-toggle {
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.dropdown-arrow {
    font-size: 0.7rem;
    transition: transform 0.3s ease;
}

.has-dropdown:hover .dropdown-arrow {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--white);
    min-width: 220px;
    box-shadow: var(--shadow-hover);
    border-radius: 4px;
    list-style: none;
    padding: 0.5rem 0;
    margin: 0;
    margin-top: 0.5rem;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    z-index: 1000;
}

.has-dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu li {
    margin: 0;
}

.dropdown-menu a {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.7rem 1rem;
    color: var(--text-color);
    text-decoration: none;
    transition: background-color 0.2s ease;
}

.dropdown-menu a:hover {
    background-color: var(--bg-color);
}

.calc-icon {
    font-size: 1.2rem;
}

/* View All Menu Item */
.view-all-item {
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 0.5rem;
}

.view-all-link {
    font-weight: 600;
}

.view-all-link:hover {
    background-color: rgba(0, 51, 102, 0.05) !important;
}

/* Prevent body scroll when mobile nav is open */
body.nav-open {
    overflow: hidden;
}

/* Desktop/Mobile Language Switcher Toggle */
.mobile-lang {
    display: none;
}

.desktop-lang {
    display: flex;
}

/* Mobile Responsive Styles */
@media (max-width: 768px) {
    .header-content {
        display: flex;
        align-items: center;
        justify-content: space-between;
        gap: 0.5rem;
    }
    
    .site-logo {
        flex: 0 0 auto;
        order: 1;
    }
    
    .mobile-menu-toggle {
        display: flex;
        flex: 0 0 auto;
        order: 3;
    }
    
    .main-nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background-color: var(--primary-color);
        flex-direction: column;
        justify-content: flex-start;
        align-items: stretch;
        padding: 5rem 0 2rem;
        transition: right 0.3s ease;
        z-index: 1000;
        overflow-y: auto;
        gap: 0;
    }
    
    .main-nav.active {
        right: 0;
        box-shadow: -5px 0 15px rgba(0, 0, 0, 0.3);
    }
    
    .nav-menu {
        flex-direction: column;
        align-items: stretch;
        width: 100%;
        gap: 0;
    }
    
    .nav-item {
        width: 100%;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }
    
    .nav-item > a {
        padding: 1rem 1.5rem;
        border-radius: 0;
    }
    
    /* Mobile Dropdown Styles */
    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background-color: rgba(0, 0, 0, 0.2);
        margin: 0;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
        border-radius: 0;
    }
    
    .has-dropdown.active .dropdown-menu {
        max-height: 1000px;
        overflow-y: auto;
    }
    
    .has-dropdown.active .dropdown-arrow {
        transform: rotate(180deg);
    }
    
    .dropdown-menu a {
        padding: 0.8rem 2rem;
        color: var(--white);
        font-size: 0.9rem;
    }
    
    .dropdown-menu a:hover {
        background-color: rgba(255, 255, 255, 0.1);
    }
    
    /* Hide desktop language switcher on mobile */
    .desktop-lang {
        display: none;
    }
    
    /* Show mobile language switcher */
    .mobile-lang {
        display: flex;
        flex: 0 0 auto;
        order: 2;
        align-items: center;
    }
    
    .mobile-lang select {
        font-size: 0.85rem;
        padding: 0.3rem 0.6rem;
        background-color: var(--white);
        color: var(--primary-color);
        border: none;
        border-radius: 4px;
        cursor: pointer;
    }
}

/* Breadcrumb */
.breadcrumb {
    background-color: var(--white);
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--border-color);
}

.breadcrumb-list {
    display: flex;
    list-style: none;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
}

.breadcrumb-item:not(:last-child)::after {
    content: '/';
    margin-left: 0.5rem;
    color: #999;
}

.breadcrumb-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.breadcrumb-item a:hover {
    text-decoration: underline;
}

.breadcrumb-item span {
    color: #666;
}

/* Main Content */
.main-content {
    padding: 2rem 0;
    min-height: calc(100vh - 200px);
}

/* Two-Column Layout with Sidebar */
.content-with-sidebar {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: 2rem;
    align-items: start;
}

.main-calculator-content {
    min-width: 0; /* Prevent overflow */
}

/* Homepage */
.page-title {
    color: var(--primary-color);
    margin-bottom: 2rem;
    font-size: 2rem;
}

.categories-section {
    display: grid;
    gap: 2rem;
}

.category-block {
    background-color: var(--white);
    border-radius: 4px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.category-title {
    color: var(--accent-color);
    margin-bottom: 1rem;
    font-size: 1.5rem;
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: 0.5rem;
}

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.calculator-card {
    display: block;
    padding: 1rem;
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    text-decoration: none;
    color: var(--text-color);
    transition: all 0.3s ease;
}

.calculator-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-color);
}

.calculator-card h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.calculator-card p {
    font-size: 0.9rem;
    color: #666;
}

/* Calculator Page */
.calculator-wrapper {
    width: 100%;
    max-width: 100%;
}

.calculator-header {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 4px;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.calculator-title {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.calculator-description {
    color: #555;
    font-size: 1.05rem;
    line-height: 1.7;
    font-style: italic;
    border-left: 3px solid var(--accent-color);
    padding-left: 1rem;
    margin-top: 1rem;
}

.calculator-form {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 4px;
    box-shadow: var(--shadow);
}

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

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
    font-weight: 500;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.7rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 51, 102, 0.1);
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
    width: auto;
}

.button-group {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.btn {
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.btn-primary:hover {
    background-color: #004080;
}

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

.btn-secondary:hover {
    background-color: #3d6820;
}

.btn-calculate {
    background-color: var(--primary-color);
    color: var(--white);
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-calculate:hover {
    background-color: #004080;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,51,102,0.3);
}

.btn-reset {
    background-color: var(--accent-color);
    color: var(--white);
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-reset:hover {
    background-color: #3d6820;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(45,80,22,0.3);
}

/* Result Display */
.result-section {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 4px;
    margin-top: 2rem;
    box-shadow: var(--shadow);
    display: none;
}

.result-section.show {
    display: block;
}

.result-title {
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.result-item {
    padding: 0.8rem;
    background-color: var(--bg-color);
    border: 1px solid #ccc;
    margin-bottom: 0.8rem;
    border-radius: 4px;
}

.result-label {
    font-weight: 500;
    color: var(--primary-color);
    margin-right: 0.5rem;
}

.result-value {
    color: var(--text-color);
    font-size: 1.1rem;
}

.error-message {
    background-color: #fee;
    color: #c33;
    padding: 1rem;
    border-radius: 4px;
    border: 1px solid #ccc;
}

/* Footer */
.site-footer {
    background-color: var(--primary-color);
    color: var(--white);
    padding: 2rem 0;
    margin-top: 3rem;
    text-align: center;
}

.site-footer p {
    margin: 0.5rem 0;
}

/* Sidebar Styles */
.calculator-sidebar {
    background-color: var(--white);
    border-radius: 4px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    position: sticky;
    top: 2rem;
    max-height: calc(100vh - 4rem);
    overflow-y: auto;
}

.sidebar-search {
    margin-bottom: 2rem;
    position: relative;
}

.search-input {
    width: 100%;
    padding: 0.8rem 1rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 0.95rem;
    transition: border-color 0.3s;
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.search-results {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin-top: 0.5rem;
    background-color: var(--white);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    max-height: 300px;
    overflow-y: auto;
    z-index: 100;
}

.search-result-item {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    padding: 0.8rem 1rem;
    text-decoration: none;
    color: var(--text-color);
    border-bottom: 1px solid var(--bg-color);
    transition: background-color 0.2s;
}

.search-result-item:last-child {
    border-bottom: none;
}

.search-result-item:hover {
    background-color: var(--bg-color);
    color: var(--primary-color);
}

.search-icon {
    font-size: 1rem;
}

.no-results {
    padding: 1rem;
    text-align: center;
    color: #999;
    font-size: 0.9rem;
}

.sidebar-title {
    color: var(--primary-color);
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.8rem;
    border-bottom: 2px solid var(--primary-color);
}

.sidebar-category {
    margin-bottom: 1.5rem;
}

.category-heading {
    color: var(--accent-color);
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

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

.calculator-list li {
    margin-bottom: 0.3rem;
}

.calculator-link {
    display: block;
    padding: 0.5rem 0.8rem;
    text-decoration: none;
    color: var(--text-color);
    border-radius: 4px;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.calculator-link:hover {
    background-color: var(--bg-color);
    color: var(--primary-color);
    padding-left: 1.2rem;
}

/* Global KaTeX Responsive Styles */
.katex-display {
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
    max-width: 100%;
}

.katex {
    max-width: 100%;
}

.formulas-section h2 {
    margin: 1rem 0rem;
}

.examples-section h2 {
    margin: 1rem 0rem;
}

.faq-section h2 {
    margin: 2rem 0rem;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .content-with-sidebar {
        grid-template-columns: 1fr 280px;
        gap: 1.5rem;
    }
    
    .calculator-sidebar {
        padding: 1.2rem;
    }
}

@media (max-width: 768px) {
    .content-with-sidebar {
        grid-template-columns: 1fr;
    }
    
    .calculator-sidebar {
        position: static;
        max-height: none;
        margin-top: 2rem;
        order: 2;
    }
    
    .main-calculator-content {
        order: 1;
    }
    
    .calculator-grid {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .button-group {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .page-title {
        font-size: 1.5rem;
    }
    
    /* Global KaTeX formula sizing on tablets */
    .katex {
        font-size: 0.95em !important;
    }
}

/* Global Action Buttons Styling */
.btn-action {
    flex: 1;
    min-width: 150px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.8rem 1.5rem;
    background-color: var(--white);
    border: 2px solid var(--primary-color);
    border-radius: 4px;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-action:hover {
    background-color: var(--primary-color);
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 51, 102, 0.2);
}

.btn-action svg {
    stroke-width: 2.5;
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .calculator-form,
    .calculator-header,
    .result-section {
        padding: 1.5rem;
    }
    
    /* Global KaTeX formula sizing on mobile */
    .katex {
        font-size: 0.9em !important;
    }
    
    .katex-display {
        font-size: 0.85em;
    }
}