/* Base Styles */
:root {
    --primary-color: #4a6baf;
    --primary-dark: #3a5a9f;
    --secondary-color: #6c757d;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Layout */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Header & Navigation */
header {
    background-color: white;
    box-shadow: var(--box-shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

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

.nav-links li {
    margin-left: 1.5rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--dark-color);
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.nav-links a i {
    font-size: 0.9rem;
}

/* Main Content */
main {
    flex: 1;
    padding: 2rem 0;
}

.content-container {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
    margin-bottom: 2rem;
}

h1 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-size: 2rem;
}

.calculator-description {
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

/* Calculator Form */
.calculator-form {
    margin-bottom: 2rem;
}

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

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

select, input[type="number"] {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

select:focus, input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(74, 107, 175, 0.2);
}

input[type="number"] {
    -moz-appearance: textfield;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.input-group {
    display: flex;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.input-group input {
    flex: 1;
    border: none;
    border-radius: 0;
}

.input-group select {
    width: auto;
    border: none;
    border-left: 1px solid #ddd;
    background-color: #f8f9fa;
}

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

.primary-button, .secondary-button {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.primary-button {
    background-color: var(--primary-color);
    color: white;
    flex: 1;
}

.primary-button:hover {
    background-color: var(--primary-dark);
}

.secondary-button {
    background-color: #f8f9fa;
    color: var(--dark-color);
    border: 1px solid #ddd;
}

.secondary-button:hover {
    background-color: #e9ecef;
}

/* Results Section */
.result-container {
    background-color: #f8f9fa;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 2rem;
}

.result-container h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.result-item {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    text-align: center;
    box-shadow: var(--box-shadow);
}

.highlight {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-color);
    display: block;
    margin-bottom: 0.5rem;
}

.result-item label {
    font-size: 0.9rem;
    color: var(--secondary-color);
}

.calculation-breakdown {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--box-shadow);
}

.calculation-breakdown h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.calculation-breakdown p {
    line-height: 1.8;
}

/* Info Section */
.info-section {
    margin-top: 2rem;
}

.info-section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.tips-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.tip-card {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.tip-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.tip-card i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.tip-card h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.tip-card p {
    color: var(--secondary-color);
    font-size: 0.9rem;
}

/* Footer */
footer {
    background-color: var(--dark-color);
    color: white;
    padding: 2rem 0;
    margin-top: auto;
}

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

.footer-section h4 {
    color: white;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

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

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

.footer-section a {
    color: #adb5bd;
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    text-align: center;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid #495057;
    color: #adb5bd;
    font-size: 0.9rem;
}

/* Dark Mode Toggle */
.dark-mode-toggle {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--primary-color);
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: var(--box-shadow);
    z-index: 99;
    transition: var(--transition);
}

.dark-mode-toggle:hover {
    background-color: var(--primary-dark);
    transform: scale(1.1);
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary-color);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    z-index: 100;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.toast.show {
    opacity: 1;
}

/* Dark Mode Styles */
body.dark-mode {
    background-color: #121212;
    color: #e0e0e0;
}

body.dark-mode header {
    background-color: #1e1e1e;
}

body.dark-mode .content-container,
body.dark-mode .result-container,
body.dark-mode .calculation-breakdown,
body.dark-mode .tip-card {
    background-color: #1e1e1e;
    color: #e0e0e0;
}

body.dark-mode select,
body.dark-mode input[type="number"],
body.dark-mode .input-group {
    background-color: #2d2d2d;
    color: #e0e0e0;
    border-color: #444;
}

body.dark-mode .input-group select {
    background-color: #2d2d2d;
}

body.dark-mode .secondary-button {
    background-color: #2d2d2d;
    border-color: #444;
    color: #e0e0e0;
}

body.dark-mode footer {
    background-color: #121212;
}

body.dark-mode .footer-section a {
    color: #aaa;
}

/* Responsive Design */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        align-items: flex-start;
    }

    .nav-links {
        margin-top: 1rem;
    }

    .nav-links li {
        margin-left: 0;
        margin-right: 1.5rem;
    }

    .button-group {
        flex-direction: column;
    }
}