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

body {
    font-family: Arial, Helvetica, sans-serif;
    color: #333;
    background-color: #fff;
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: #333;
}

ul {
    list-style: none;
}

.container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    max-width: 900px;
    margin: 60px auto 0 auto;
    padding: 0 24px;
}

/* Desktop Header */
.desktop-header {
    padding: 1.5rem 0;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.header-content {
    display: flex;
    flex-direction: column;
}

.logo {
    font-size: 1.875rem;
    font-weight: bold;
    color: #333;
}

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

.desktop-nav ul {
    display: flex;
    gap: 2rem;
    align-items: center;
    justify-content: flex-start;
}

.desktop-nav ul li:last-child {
    margin-left: 0;
}

.desktop-nav a {
    color: #333;
    transition: color 0.3s;
}

.desktop-nav a:hover {
    color: #666;
}

/* Mobile Header */
.mobile-header {
    padding: 0.75rem 1rem;
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: 40;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.mobile-header .header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-direction: row;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 0.5rem;
}

.mobile-header .logo {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.5px;
}

.mobile-controls {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.menu-toggle {
    display: flex;
    align-items: center;
    padding: 0.5rem;
    border: none;
    border-radius: 0.5rem;
    background: none;
    cursor: pointer;
    transition: all 0.2s ease;
    color: #333;
}

.menu-toggle:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

.menu-toggle:active {
    transform: scale(0.95);
}

/* Mobile Sidebar */
.mobile-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.98);
    z-index: 50;
    transform: translateX(100%);
    opacity: 0;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    visibility: hidden;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.mobile-sidebar.active {
    transform: translateX(0);
    opacity: 1;
    visibility: visible;
}

.sidebar-content {
    padding: 1.5rem;
    height: 100%;
    max-width: 400px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.8);
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.sidebar-header .logo {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.5px;
}

.close-menu {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.75rem;
    border-radius: 9999px;
    transition: all 0.2s ease;
    color: #333;
}

.close-menu:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

.close-menu:active {
    transform: scale(0.95);
}

.mobile-nav {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.mobile-nav ul {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.mobile-nav a {
    font-size: 1.125rem;
    color: #333;
    display: block;
    padding: 0.75rem 1rem;
    transition: all 0.2s ease;
    border-radius: 0.5rem;
    font-weight: 500;
}

.mobile-nav a:hover {
    background-color: rgba(0, 0, 0, 0.05);
    color: #5b21b6;
}

.mobile-nav a:active {
    transform: scale(0.98);
}

/* Main Content */
main {
    flex: 1;
}

h1 {
    font-size: 2.5rem;
    font-weight: 400;
    margin-bottom: 16px;
}

.subtitle {
    color: #666;
    font-size: 1rem;
    margin-bottom: 48px;
}

.video-title {
    font-size: 2rem;
    font-weight: 400;
    margin-bottom: 8px;
}

.video-desc {
    color: #666;
    font-size: 1rem;
    margin-bottom: 16px;
}

.video-embed {
    margin-top: 16px;
    margin-bottom: 60px;
}

.video-embed video {
    width: 100%;
    max-width: 1280px;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

/* Footer */
footer {
    margin-top: auto;
    padding: 1.5rem 0;
    display: block;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    font-size: 0.875rem;
    color: #6b7280;
    display: block;
}

.footer-content a {
    color: #333;
}

.footer-content a:hover {
    text-decoration: underline;
}

/* Language Toggle Link */
.lang-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: 1px solid #e5e7eb;
    border-radius: 0.5rem;
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    color: #333;
    text-decoration: none;
    gap: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
}

.lang-toggle:hover {
    background-color: #5b21b6;
    color: white;
    border-color: #5b21b6;
    text-decoration: none;
}

.lang-toggle .icon {
    width: 20px;
    height: 20px;
}

.lang-toggle span {
    font-size: 0.875rem;
}

/* Media Queries */
@media (max-width: 768px) {
    .desktop-header {
        display: none;
    }

    .mobile-header {
        display: block;
    }

    .container {
        margin: 40px 0 0 0;
        padding: 0 16px;
    }

    .lang-toggle {
        padding: 0.5rem;
        border-radius: 0.5rem;
        background: rgba(0, 0, 0, 0.05);
        border: none;
    }

    .lang-toggle:hover {
        background: rgba(0, 0, 0, 0.1);
    }

    .lang-toggle:active {
        transform: scale(0.95);
    }

    .lang-toggle .icon {
        width: 18px;
        height: 18px;
    }

    .lang-toggle span {
        display: none;
    }
}