:root {
    /* Color Palette - Modern Dark Theme with Vibrant Accents */
    --bg-primary: hsl(220, 18%, 10%);
    --bg-secondary: hsl(220, 18%, 14%);
    --bg-tertiary: hsl(220, 18%, 18%);
    --bg-glass: hsla(220, 18%, 20%, 0.7);
    
    --text-primary: hsl(0, 0%, 98%);
    --text-secondary: hsl(220, 10%, 70%);
    --text-muted: hsl(220, 10%, 50%);
    
    --accent-primary: hsl(142, 70%, 45%);
    --accent-secondary: hsl(142, 70%, 55%);
    --accent-gradient: linear-gradient(135deg, hsl(142, 70%, 45%), hsl(142, 70%, 60%));
    
    --success: hsl(142, 70%, 45%);
    --error: hsl(0, 70%, 55%);
    --warning: hsl(38, 92%, 50%);
    --info: hsl(210, 100%, 60%);
    
    --border-color: hsl(220, 18%, 25%);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(37, 211, 102, 0.3);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* Background Animation */
body::before {
    content: '';
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 20% 50%, hsla(142, 70%, 45%, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 80% 80%, hsla(210, 100%, 60%, 0.1) 0%, transparent 50%);
    animation: backgroundShift 20s ease infinite;
    z-index: -1;
    pointer-events: none;
}

@keyframes backgroundShift {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(-5%, -5%); }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md);
}

/* Header */
.header {
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg) 0;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.75rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: fadeInDown 0.6s ease;
}

.logo-icon {
    width: 40px;
    height: 40px;
    stroke: var(--accent-primary);
    filter: drop-shadow(var(--shadow-glow));
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Status Badge */
.status-badge {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    font-size: 0.875rem;
    font-weight: 500;
    animation: fadeInDown 0.6s ease 0.2s both;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--text-muted);
    animation: pulse 2s ease infinite;
}

.status-badge.connected .status-dot {
    background: var(--success);
    box-shadow: 0 0 10px var(--success);
}

.status-badge.disconnected .status-dot {
    background: var(--error);
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* Cards */
.card {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
    animation: fadeInUp 0.6s ease both;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.card:nth-child(1) { animation-delay: 0.1s; }
.card:nth-child(2) { animation-delay: 0.2s; }
.card:nth-child(3) { animation-delay: 0.3s; }
.card:nth-child(4) { animation-delay: 0.4s; }

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card-header {
    margin-bottom: var(--spacing-md);
}

.card-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* QR Code Section */
.qr-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 300px;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.qr-placeholder {
    text-align: center;
    color: var(--text-secondary);
}

.qr-code {
    max-width: 280px;
    width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    animation: scaleIn 0.4s ease;
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.8);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--border-color);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--spacing-sm);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.qr-instructions {
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
}

.qr-instructions ol {
    margin-left: var(--spacing-md);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.qr-instructions li {
    margin-bottom: var(--spacing-xs);
}

.qr-instructions strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* Connected Section */
.connected-content {
    text-align: center;
    padding: var(--spacing-lg) 0;
}

.success-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-glow);
    animation: successPulse 2s ease infinite;
}

.success-icon svg {
    width: 100%;
    height: 100%;
    stroke: white;
}

@keyframes successPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

/* Form Styles */
.message-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.form-group label {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.9375rem;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px hsla(142, 70%, 45%, 0.1);
}

.form-group small {
    color: var(--text-muted);
    font-size: 0.8125rem;
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 0.9375rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: inherit;
}

.btn svg {
    width: 18px;
    height: 18px;
}

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

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

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

/* Activity Log */
.activity-log {
    max-height: 400px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.activity-log::-webkit-scrollbar {
    width: 8px;
}

.activity-log::-webkit-scrollbar-track {
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
}

.activity-log::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: var(--radius-sm);
}

.activity-log::-webkit-scrollbar-thumb:hover {
    background: var(--accent-primary);
}

.activity-item {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--accent-primary);
    animation: slideInRight 0.3s ease;
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.activity-time {
    font-size: 0.75rem;
    color: var(--text-muted);
    white-space: nowrap;
    min-width: 80px;
}

.activity-message {
    font-size: 0.875rem;
    color: var(--text-secondary);
    flex: 1;
}

.activity-item.success {
    border-left-color: var(--success);
}
@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.toast-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.toast-icon {
    font-size: 1.25rem;
}

.toast.success {
    border-left: 4px solid var(--success);
}

.toast.error {
    border-left: 4px solid var(--error);
}

.toast.info {
    border-left: 4px solid var(--info);
}

/* Footer */
.footer {
    text-align: center;
    padding: var(--spacing-lg) 0;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.heart {
    color: var(--error);
    animation: heartbeat 1.5s ease infinite;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    10%, 30% { transform: scale(1.1); }
    20%, 40% { transform: scale(1); }
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Login Overlay */
.login-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.login-card {
    width: 100%;
    max-width: 400px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-sm);
    }
    
    .header-content {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .logo {
        font-size: 1.5rem;
    }
    
    .card {
        padding: var(--spacing-md);
    }
    
    .toast {
        bottom: var(--spacing-sm);
        right: var(--spacing-sm);
        left: var(--spacing-sm);
        max-width: none;
    }
}