:root {
    --primary-color: #4a90e2;
    --secondary-color: #2c3e50;
    --background-color: #f5f6fa;
    --text-color: #2c3e50;
    --border-color: #dcdde1;
}

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

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

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

header p {
    font-size: 1.1rem;
    color: var(--secondary-color);
}

section {
    margin-bottom: 3rem;
    background: white;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    padding: 2rem;
}

.player-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

.video-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    background: #000;
    border-radius: 8px;
    overflow: hidden;
    margin-bottom: 1rem;
}

#videoElement {
    width: 100%;
    aspect-ratio: 16/9;
    background: #000;
    border-radius: 8px;
}

.controls {
    margin-top: 1rem;
    display: flex;
    justify-content: center;
}

.file-input-container {
    flex: 0 1 auto;
    min-width: 200px;
}

.file-input-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: white;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
    justify-content: center;
}

.file-input-label:hover {
    background-color: #357abd;
}

#fileInput {
    display: none;
}

.control-button {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 5px;
    background-color: var(--secondary-color);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: background-color 0.3s;
}

.control-button:hover {
    background-color: #1a252f;
}

.control-button i {
    font-size: 1rem;
}

.features-section h2,
.faq-section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

.features-section ul {
    list-style: none;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.features-section li {
    padding: 1rem;
    background: var(--background-color);
    border-radius: 8px;
    text-align: center;
    font-size: 1.1rem;
}

.faq-item {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--background-color);
    border-radius: 8px;
}

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

.faq-item p {
    color: var(--text-color);
}

footer {
    text-align: center;
    padding: 2rem 0;
    color: var(--secondary-color);
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
    margin-top: 2rem;
}

footer p {
    margin-bottom: 0.5rem;
}

@media (max-width: 768px) {
    .app-container {
        padding: 1rem;
    }

    header h1 {
        font-size: 2rem;
    }

    section {
        padding: 1.5rem;
    }

    .controls {
        flex-direction: column;
    }

    .file-input-container {
        width: 100%;
    }

    .control-button {
        width: 100%;
        justify-content: center;
    }

    .features-section ul {
        grid-template-columns: 1fr;
    }
}

.intro-section {
    text-align: center;
    margin-bottom: 2rem;
}

.intro-content {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.1rem;
    line-height: 1.8;
}

.player-instructions {
    text-align: center;
    margin-bottom: 1rem;
    color: var(--primary-color);
    font-size: 1.2rem;
}

.feature-icon {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.features-section li {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem;
}

.features-section h3 {
    margin: 1rem 0;
    color: var(--secondary-color);
}

.usage-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.step {
    text-align: center;
    padding: 2rem;
    background: var(--background-color);
    border-radius: 8px;
    position: relative;
}

.step-number {
    position: absolute;
    top: -1rem;
    left: 50%;
    transform: translateX(-50%);
    width: 2.5rem;
    height: 2.5rem;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.2rem;
}

.step h3 {
    margin: 1rem 0;
    color: var(--secondary-color);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 2rem;
    padding: 1.5rem;
    border-radius: 8px;
    background: var(--background-color);
    transition: transform 0.3s ease;
}

.faq-item:hover {
    transform: translateY(-2px);
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
}

.disclaimer {
    margin-top: 1rem;
    font-size: 0.8rem;
    color: #666;
}

@media (max-width: 768px) {
    .intro-content {
        padding: 0 1rem;
        font-size: 1rem;
    }

    .usage-steps {
        grid-template-columns: 1fr;
    }

    .step {
        padding: 1.5rem;
    }

    .features-section li {
        padding: 1.5rem;
    }
}