/* Base Styles */
:root {
    --primary-color: #007bff;
    --primary-dark: #0056b3;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --light-bg: #f8f9fa;
    --white: #ffffff;
    --shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    --transition: all 0.2s ease;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --container-width: 1200px;
    --border-radius: 4px;
    --header-height: 60px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--light-bg);
    margin: 0;
    padding: 0;
    padding-top: var(--header-height);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    line-height: 1.6;
    color: #333;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-bottom: var(--spacing-md);
    color: #333;
    line-height: 1.2;
    font-weight: 600;
}

h1 { font-size: 2rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.1rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
}

/* Layout Components */
.container {
    width: 100%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: var(--spacing-md);
}

.card {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: var(--spacing-lg);
    margin: var(--spacing-md);
    transition: var(--transition);
}

/* Navigation */
.navbar {
    background-color: var(--primary-color);
    padding: 0;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
    height: var(--header-height);
    display: flex;
    align-items: center;
}

.navbar-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    width: 100%;
    height: 100%;
    position: relative;
}

.brand-logo {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--white);
    text-decoration: none;
    padding: var(--spacing-sm) 0;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    width: 44px;
    height: 44px;
    cursor: pointer;
    position: relative;
    z-index: 1001;
    padding: 10px;
    margin: -10px;
    touch-action: manipulation;
}

.menu-icon {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--white);
    position: relative;
    transition: var(--transition);
}

.menu-icon::before,
.menu-icon::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 2px;
    background-color: var(--white);
    transition: var(--transition);
}

.menu-icon::before {
    top: -6px;
}

.menu-icon::after {
    bottom: -6px;
}

.mobile-menu-btn.active .menu-icon {
    background-color: transparent;
}

.mobile-menu-btn.active .menu-icon::before {
    transform: rotate(45deg);
    top: 0;
}

.mobile-menu-btn.active .menu-icon::after {
    transform: rotate(-45deg);
    bottom: 0;
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    list-style: none;
    margin: 0;
    padding: 0;
    height: 100%;
}

.nav-links li {
    height: 100%;
}

.nav-links a {
    color: var(--white);
    text-decoration: none;
    padding: 0 var(--spacing-md);
    height: 100%;
    display: flex;
    align-items: center;
    transition: var(--transition);
}

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

/* Form Elements */
.input-field {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background-color: var(--white);
}

.input-field:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 2px rgba(0, 123, 255, 0.25);
}

select.input-field {
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    background-size: 1em;
    padding-right: 2.5rem;
}

textarea.input-field {
    min-height: 100px;
    resize: vertical;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    gap: 0.5rem;
    background-color: var(--primary-color);
    color: var(--white);
}

.btn:hover:not(:disabled) {
    background-color: var(--primary-dark);
}

.btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

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

.btn-secondary:hover:not(:disabled) {
    background-color: #5a6268;
}

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

.btn-success:hover:not(:disabled) {
    background-color: #218838;
}

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

.btn-danger:hover:not(:disabled) {
    background-color: #c82333;
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--spacing-md);
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* Utility Classes */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-sm { gap: var(--spacing-sm); }
.gap-md { gap: var(--spacing-md); }
.gap-lg { gap: var(--spacing-lg); }
.text-center { text-align: center; }
.hidden { display: none; }

/* Footer */
.footer {
    background-color: var(--primary-color);
    color: var(--white);
    padding: var(--spacing-lg);
    margin-top: auto;
}

.footer-content {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    text-align: center;
    max-width: var(--container-width);
    margin: 0 auto;
}

/* Responsive Design */
@media (max-width: 1200px) {
    :root {
        --container-width: 100%;
    }
}

@media (max-width: 992px) {
    .grid-4 {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }

    .mobile-menu-btn {
        display: block;
    }

    .card {
        margin: var(--spacing-sm);
        padding: var(--spacing-md);
    }

    .nav-links {
        display: none;
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background-color: var(--primary-color);
        flex-direction: column;
        padding: 0;
        gap: 0;
        height: auto;
        z-index: 1000;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    }

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

    .nav-links li {
        width: 100%;
        height: auto;
    }

    .nav-links a {
        padding: 1rem var(--spacing-md);
        width: 100%;
        height: auto;
        min-height: 44px;
        border-bottom: 1px solid var(--primary-dark);
    }

    .nav-links li:last-child a {
        border-bottom: none;
    }

    .grid-3, .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }

    .btn {
        width: 100%;
    }
}

@media (max-width: 576px) {
    .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }

    .container {
        padding: var(--spacing-sm);
    }

    .brand-logo {
        font-size: 1.1rem;
    }

    .input-field {
        font-size: 16px;
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --light-bg: #1a1a1a;
        --white: #2d2d2d;
    }

    body {
        color: #e0e0e0;
    }

    h1, h2, h3, h4, h5, h6 {
        color: #e0e0e0;
    }

    .input-field {
        background-color: #333;
        color: #e0e0e0;
        border-color: #444;
    }

    .input-field:focus {
        border-color: var(--primary-color);
    }

    select.input-field {
        background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23e0e0e0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    }
}