```css
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600;700&display=swap');

body {
    font-family: 'Poppins', sans-serif;
    background-color: #111827;
    color: #f3f4f6;
}

/* Custom scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #1f2937;
}

::-webkit-scrollbar-thumb {
    background: #f97316;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #ea580c;
}

/* Animation classes */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.fade-in {
    animation: fadeIn 0.5s ease-in-out;
}

/* Utility classes */
.max-w-8xl {
    max-width: 90rem;
}

.min-h-80 {
    min-height: 20rem;
}

.hover-grow {
    transition: transform 0.2s ease;
}

.hover-grow:hover {
    transform: scale(1.05);
}

/* Responsive video container */
.video-container {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
}

.video-container iframe,
.video-container object,
.video-container embed {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* Gradient text */
.text-gradient {
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Tooltip */
.tooltip {
    position: relative;
}

.tooltip::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: #1f2937;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    white-space: nowrap;
    opacity: 0;
    transition: opacity 0.2s;
    pointer-events: none;
    z-index: 10;
}

.tooltip:hover::after {
    opacity: 1;
}

/* Custom checkbox */
.custom-checkbox input[type="checkbox"] {
    opacity: 0;
    position: absolute;
}

.custom-checkbox .checkmark {
    position: relative;
    display: inline-block;
    width: 1.25rem;
    height: 1.25rem;
    background-color: #1f2937;
    border: 2px solid #f97316;
    border-radius: 0.25rem;
    margin-right: 0.5rem;
}

.custom-checkbox input[type="checkbox"]:checked + .checkmark {
    background-color: #f97316;
}

.custom-checkbox .checkmark::after {
    content: "";
    position: absolute;
    display: none;
    left: 0.375rem;
    top: 0.125rem;
    width: 0.3125rem;
    height: 0.625rem;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.custom-checkbox input[type="checkbox"]:checked + .checkmark::after {
    display: block;
}
```