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

.light-theme {
    --bg-color: #f5f5f5;
    --text-color: #000;
    --header-bg: #000;
    --header-text: #fff;
    --accent-green: #0f0;
    --accent-red: red;
    --nav-hover: #333;
}

.dark-theme {
    --bg-color: #000;
    --text-color: #fff;
    --header-bg: #1a1a1a;
    --header-text: #fff;
    --accent-green: #0c0;
    --accent-red: #c00;
    --nav-hover: #2a2a2a;
}

.light-theme .content-wrapper {
    background: rgba(255, 255, 255, 0.95);
    color: #000;
}

.light-theme h2 {
    color: #0a0;
}

.light-theme .welcome-box {
    background: rgba(0, 255, 0, 0.15);
    color: #000;
}

body {
    font-family: Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    padding-top: 110px;
    transition: all 0.3s ease;
}

.fixed-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--header-bg);
    color: var(--header-text);
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 5px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo {
    height: 100px;
    width: auto;
    max-width: 150px;
    object-fit: contain;
}

.sender-name {
    font-size: 1.6em;
    color: #0f0;
    text-shadow: 0 0 10px #0f0, 0 0 20px #0f0, 0 0 30px #0f0, 2px 2px 4px rgba(0, 0, 0, 0.5);
    animation: neon-pulse 2s ease-in-out infinite;
    white-space: nowrap;
}

@keyframes neon-pulse {
    0%, 100% {
        text-shadow: 0 0 10px #0f0, 0 0 20px #0f0, 0 0 30px #0f0;
    }
    50% {
        text-shadow: 0 0 20px #0f0, 0 0 30px #0f0, 0 0 40px #0f0, 0 0 50px #0f0;
    }
}

.header-right {
    display: flex;
    align-items: center;
    gap: 15px;
}

#datetime {
    display: none;
}

.theme-toggle {
    background: var(--accent-green);
    border: none;
    padding: 10px 15px;
    font-size: 1.2em;
    cursor: pointer;
    border-radius: 5px;
    transition: all 0.3s;
    color: #000;
}

.light-theme .theme-toggle {
    background: #fff;
    color: #000;
    border: 2px solid #0f0;
}

.dark-theme .theme-toggle {
    background: #0f0;
    color: #000;
}

.theme-toggle:hover {
    transform: scale(1.1);
    background: #f00;
    color: #fff;
}

nav {
    background: var(--nav-hover);
    display: flex;
    justify-content: center;
    gap: 8px;
    padding: 8px;
    flex-wrap: wrap;
    max-width: 1200px;
    margin: 0 auto;
}

nav a, .play-btn {
    color: var(--header-text);
    text-decoration: none;
    padding: 8px 15px;
    border-radius: 5px;
    transition: all 0.3s;
    border: 2px solid transparent;
    font-size: 0.95em;
}

nav a:hover, .play-btn:hover {
    background: var(--accent-green);
    color: #000;
}

nav a.active {
    border-color: var(--accent-red);
}

.play-btn {
    background: var(--accent-red);
    border: none;
    cursor: pointer;
    font-weight: bold;
}

main {
    min-height: calc(100vh - 150px);
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    padding: 30px;
    position: relative;
}

main::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    z-index: 0;
}

main .content-wrapper {
    position: relative;
    z-index: 1;
}

.content-wrapper {
    max-width: 1200px;
    margin: 0 auto;
    background: rgba(0, 0, 0, 0.8);
    padding: 30px;
    border-radius: 10px;
}

.dark-theme .content-wrapper {
    background: rgba(20, 20, 20, 0.95);
}

h2 {
    color: var(--accent-green);
    margin-bottom: 20px;
    border-bottom: 2px solid var(--accent-red);
    padding-bottom: 10px;
}

.welcome-box {
    background: rgba(0, 255, 0, 0.1);
    padding: 30px;
    border-radius: 10px;
    border-left: 5px solid var(--accent-green);
    margin: 20px 0;
    font-size: 1.2em;
    line-height: 1.8;
}

.no-content {
    text-align: center;
    padding: 60px;
    background: rgba(255, 255, 0, 0.1);
    border-radius: 10px;
    border: 2px dashed var(--accent-green);
}

@media (max-width: 768px) {
    .header-left {
        flex-direction: column;
        gap: 10px;
    }
    
    .sender-name {
        font-size: 1.5em;
    }
    
    nav {
        flex-direction: column;
    }
    
    body {
        padding-top: 250px;
    }
}