@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&family=Inter:wght@400;500;600&display=swap');

:root {
    --primary-color: #7C4DFF;
    --primary-hover: #651FFF;
    --text-color: #2d3436;
    --bg-color: #f7f7ff;
    --card-bg: white;
    --border-color: #e6e6ff;
    --header-bg: #5E35B1;
    --footer-bg: #4527A0;
    --shadow-color: rgba(124, 77, 255, 0.1);
    --gradient-start: #7C4DFF;
    --gradient-end: #651FFF;
    --transition: all 0.3s ease;
    --heading-font: 'Poppins', sans-serif;
    --body-font: 'Inter', sans-serif;
}

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

body {
    font-family: var(--body-font);
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: var(--transition);
    line-height: 1.6;
    background-image: linear-gradient(135deg, var(--bg-color) 0%, rgba(124, 77, 255, 0.05) 100%);
    font-size: 16px;
    font-weight: 400;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--heading-font);
    font-weight: 600;
    line-height: 1.3;
    letter-spacing: -0.02em;
}

/* Header Styles */
.main-header {
    background: linear-gradient(135deg, var(--header-bg), var(--primary-color));
    color: white;
    padding: 0.5rem 0;
    box-shadow: 0 1px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
}

.logo-container {
    display: flex;
    flex-direction: column;
}

.logo-container h1 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
}

.logo-container .tagline {
    font-size: 0.9rem;
    margin: 0;
    opacity: 0.9;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: clamp(1rem, 2vw, 2rem);
}

.nav-category {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: var(--transition);
    font-weight: 500;
    position: relative;
    display: inline-block;
}

.nav-category:hover {
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.menu-toggle .bar {
    display: block;
    width: 25px;
    height: 3px;
    background-color: white;
    margin: 5px 0;
    transition: var(--transition);
    border-radius: 3px;
}

/* Mobile Header Styles */
@media screen and (max-width: 768px) {
    .main-header {
        padding: 0.3rem 0;
    }

    .header-content {
        padding: 0.3rem 0;
    }

    .logo-container h1 {
        font-size: 1.2rem;
    }

    .logo-container .tagline {
        font-size: 0.8rem;
    }

    .nav-links li {
        margin-left: 0.8rem;
    }

    .nav-links a {
        font-size: 0.9rem;
        padding: 0.3rem 0;
    }

    .menu-toggle {
        display: block;
        position: absolute;
        right: 1rem;
        top: 1rem;
    }

    .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        gap: 0.5rem;
        margin-top: 1rem;
    }

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

    .menu-toggle.active .bar:nth-child(1) {
        transform: rotate(-45deg) translate(-5px, 6px);
    }

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

    .menu-toggle.active .bar:nth-child(3) {
        transform: rotate(45deg) translate(-5px, -6px);
    }
}

/* Main Content */
.main-content {
    flex: 1;
    width: min(95%, 1200px);
    margin: 2rem auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.calculator-container {
    background-color: var(--card-bg);
    border-radius: 16px;
    box-shadow: 0 8px 30px var(--shadow-color);
    padding: clamp(1.5rem, 3vw, 2.5rem);
    margin-bottom: 2rem;
    width: 100%;
    max-width: 800px;
    transition: var(--transition);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
}

.calculator-container:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px var(--shadow-color);
}

.calculator-container h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: clamp(1.5rem, 2.5vw, 2rem);
    text-align: center;
    position: relative;
    padding-bottom: 0.5rem;
}

.calculator-container h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(to right, var(--gradient-start), var(--gradient-end));
    border-radius: 3px;
}

/* Calculator Form */
.calculator-form {
    display: grid;
    gap: 1.5rem;
}

.input-group {
    display: grid;
    gap: 0.5rem;
    position: relative;
}

label {
    color: var(--text-color);
    font-size: 0.95rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--heading-font);
}

input, select {
    padding: 0.875rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    font-size: 1rem;
    background-color: var(--card-bg);
    color: var(--text-color);
    transition: var(--transition);
    width: 100%;
    font-family: var(--body-font);
}

input:hover, select:hover {
    border-color: var(--primary-color);
}

input:focus, select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--shadow-color);
}

button {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    border: none;
    padding: 1rem 1.5rem;
    border-radius: 12px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    position: relative;
    overflow: hidden;
    font-family: var(--heading-font);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-color);
}

button:active {
    transform: translateY(0);
}

/* Results Section */
.results {
    display: none;
    background-color: var(--bg-color);
    padding: 1.5rem;
    border-radius: 12px;
    margin-top: 1.5rem;
    border: 2px solid var(--border-color);
    animation: fadeIn 0.3s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.results h3 {
    color: var(--primary-color);
    font-size: 1.25rem;
    margin-bottom: 1rem;
    font-weight: 600;
    text-align: center;
    font-family: var(--heading-font);
}

.results p {
    margin-bottom: 1rem;
    color: var(--text-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem;
    border-radius: 8px;
    background-color: var(--card-bg);
}

.results ul {
    list-style: none;
    display: grid;
    gap: 0.75rem;
}

.results li {
    color: var(--text-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem;
    background-color: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 2px 4px var(--shadow-color);
}

.results span {
    color: var(--primary-color);
    font-weight: 600;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    background-color: var(--shadow-color);
    font-family: var(--heading-font);
}

/* Information Section */
.info-section {
    display: grid;
    gap: 2rem;
}

.info-card {
    background-color: var(--card-bg);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 4px 20px var(--shadow-color);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.info-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px var(--shadow-color);
}

.info-card h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    font-family: var(--heading-font);
    font-weight: 600;
    position: relative;
    padding-bottom: 0.75rem;
}

.info-card h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(to right, var(--gradient-start), var(--gradient-end));
    border-radius: 3px;
}

.info-card p {
    color: var(--text-color);
    font-size: 1rem;
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.info-list {
    list-style: none;
    display: grid;
    gap: 1rem;
}

.info-list li {
    background-color: var(--bg-color);
    padding: 1.25rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    display: grid;
    gap: 0.5rem;
}

.info-list li:hover {
    transform: translateX(5px);
    box-shadow: 0 4px 15px var(--shadow-color);
}

.info-list strong {
    color: var(--primary-color);
    font-family: var(--heading-font);
    font-weight: 600;
    font-size: 1.1rem;
    display: block;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.tip-card {
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.tip-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 15px var(--shadow-color);
}

.tip-card h4 {
    color: var(--primary-color);
    font-family: var(--heading-font);
    font-size: 1.2rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.tip-card p {
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-color);
}

/* Custom Checkbox Styling */
.checkbox-group {
    display: flex;
    align-items: center;
    margin: 8px 0;
    position: relative;
    cursor: pointer;
}

.checkbox-group input[type="checkbox"] {
    opacity: 0;
    position: absolute;
    cursor: pointer;
}

.checkbox-group label {
    padding-left: 35px;
    position: relative;
    cursor: pointer;
    font-size: 16px;
    line-height: 25px;
    color: #333;
    user-select: none;
}

.checkbox-group label:before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 22px;
    height: 22px;
    border: 2px solid #4a90e2;
    border-radius: 4px;
    background: #fff;
    transition: all 0.2s ease;
}

.checkbox-group label:after {
    content: '';
    position: absolute;
    left: 8px;
    top: 4px;
    width: 6px;
    height: 12px;
    border: solid #4a90e2;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
    opacity: 0;
    transition: all 0.2s ease;
}

.checkbox-group input[type="checkbox"]:checked + label:before {
    background: #fff;
    border-color: #4a90e2;
}

.checkbox-group input[type="checkbox"]:checked + label:after {
    opacity: 1;
}

.checkbox-group:hover label:before {
    border-color: #2171d3;
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.1);
}

.checkbox-group input[type="checkbox"]:focus + label:before {
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.2);
}

/* Checkbox group container */
.features-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    padding: 15px 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

    .main-header nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }

    .calculator-container {
        padding: 1.25rem;
    }

    .input-group {
        grid-template-columns: 1fr;
    }

    .results li {
        flex-direction: column;
        text-align: center;
        gap: 0.5rem;
    }
}

/* Performance Optimizations */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* Footer Styles */
.main-footer {
    background: linear-gradient(135deg, var(--footer-bg), var(--primary-color));
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 3rem;
}

.footer-content {
    width: min(95%, 1200px);
    margin: 0 auto;
    padding: 0 1rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    font-family: var(--heading-font);
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: white;
}

.footer-section ul {
    list-style: none;
}

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

.footer-section a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    transition: var(--transition);
}

.footer-section a:hover {
    color: white;
    text-decoration: underline;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.9);
    line-height: 1.6;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 1rem;
    margin-top: 2rem;
    text-align: center;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.version {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* Container */
.container {
    width: min(1200px, 90%);
    margin: 0 auto;
    padding: 0 1rem;
}

/* Theme Switch Styles */
.theme-switch-wrapper {
    position: fixed;
    top: 20px;
    right: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.theme-switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--primary-color);
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}

/* Tabs Styling */
.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 10px;
}

.tab-btn {
    background: none;
    border: none;
    padding: 10px 20px;
    cursor: pointer;
    color: var(--text-color);
    font-size: 16px;
    border-radius: 5px;
    transition: background-color 0.3s;
}

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

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

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Responsive Design */
@media (max-width: 600px) {
    .calculator-container {
        padding: 20px;
    }
    
    .tabs {
        flex-direction: column;
    }
    
    .theme-switch-wrapper {
        top: 10px;
        right: 10px;
    }
}