/* Dark Minimal Design */
:root {
    --bg-primary: #0a0a0a;
    --bg-secondary: #151515;
    --bg-tertiary: #1a1a1a;
    --bg-card: #121212;
    
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --text-muted: #666666;
    
    --accent-primary: #2563eb;
    --accent-hover: #3b82f6;
    --accent-muted: #1e40af;
    
    --border-color: #333333;
    --border-light: #262626;
    
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;
    
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.4);
    
    --radius: 8px;
    --radius-lg: 12px;
    
    --transition: all 0.2s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    overflow-x: hidden;
}

/* App Container */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
}

/* Header */
.header {
    background: var(--bg-secondary);
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    transition: var(--transition);
}

.dot.online {
    background: var(--success);
    box-shadow: 0 0 8px var(--success);
}

.dot.offline {
    background: var(--error);
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 2rem;
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}

/* Screen Management */
.screen {
    display: none;
}

.screen.active {
    display: block;
}

/* Welcome Screen */
.welcome-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2rem;
    text-align: center;
    margin-bottom: 2rem;
}

.welcome-card h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.welcome-card p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* Form Sections */
.form-section {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.form-section h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Input Styles */
.room-name-input,
.room-password-input,
.nickname-input,
.invitation-input,
#messageInput {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    color: var(--text-primary);
    font-size: 0.875rem;
    transition: var(--transition);
    outline: none;
}

.room-name-input:focus,
.room-password-input:focus,
.nickname-input:focus,
.invitation-input:focus,
#messageInput:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}

.room-name-input::placeholder,
.room-password-input::placeholder,
.nickname-input::placeholder,
.invitation-input::placeholder,
#messageInput::placeholder {
    color: var(--text-muted);
}

/* Button Styles */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 0.875rem;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    outline: none;
}

.btn.primary {
    background: var(--accent-primary);
    color: white;
}

.btn.primary:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

.btn.secondary {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.btn.secondary:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

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

.btn.danger:hover {
    background: #dc2626;
}

/* Chat Interface */
.chat-interface {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    height: 600px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-header {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.chat-header h3 {
    color: var(--text-primary);
    font-size: 1.125rem;
    font-weight: 600;
}

.participants-panel {
    padding: 0.75rem 1rem;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.messages-container {
    flex: 1;
    padding: 1rem;
    overflow-y: auto;
    background: var(--bg-primary);
}

.message {
    background: var(--bg-secondary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
    padding: 0.75rem;
    margin-bottom: 0.75rem;
    animation: slideIn 0.2s ease-out;
}

.message.own {
    background: var(--accent-muted);
    border-color: var(--accent-primary);
    margin-left: 20%;
}

.message-header {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 0.25rem;
    font-weight: 500;
}

.message-content {
    color: var(--text-primary);
    word-wrap: break-word;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Message Input */
.message-input-container {
    display: flex;
    padding: 1rem;
    gap: 0.75rem;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
}

.message-input-container #messageInput {
    flex: 1;
    margin-bottom: 0;
}

.message-input-container #sendBtn {
    background: var(--accent-primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

.message-input-container #sendBtn:hover {
    background: var(--accent-hover);
}

/* Error Messages */
.error-message {
    background: var(--error);
    color: white;
    padding: 0.75rem 1rem;
    border-radius: var(--radius);
    margin-bottom: 1rem;
    font-size: 0.875rem;
}

/* Form Hints */
.form-hint {
    color: var(--text-muted);
    font-size: 0.75rem;
    margin-top: 0.25rem;
}

/* Room Controls */
.room-controls {
    display: flex;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: var(--bg-tertiary);
    border-top: 1px solid var(--border-color);
}

.room-controls h4 {
    flex: 1;
    margin: 0;
    font-size: 0.875rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
}

/* Scrollbar */
.messages-container::-webkit-scrollbar {
    width: 6px;
}

.messages-container::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

.messages-container::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.messages-container::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* Responsive */
@media (max-width: 768px) {
    .main-content {
        padding: 1rem;
    }
    
    .welcome-card,
    .form-section {
        padding: 1rem;
    }
    
    .message.own {
        margin-left: 10%;
    }
    
    .hide-mobile {
        display: none;
    }
    
    .room-controls {
        flex-wrap: wrap;
    }
}

/* Additional states */
.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn:disabled:hover {
    transform: none;
}

/* Loading state */
.loading {
    opacity: 0.7;
    pointer-events: none;
}