/* ========================================
   CSS Variables & Reset
   ======================================== */

:root {
    /* Colors */
    --color-bg: #0f1115;
    --color-bg-elevated: #181c22;
    --color-surface: #1e232a;
    --color-surface-hover: #252b34;
    --color-border: #2d3440;
    --color-border-light: #3d4656;
    
    --color-primary: #00d4aa;
    --color-primary-hover: #00e8bb;
    --color-primary-muted: rgba(0, 212, 170, 0.15);
    --color-primary-text: #004d3d;
    
    --color-secondary: #6366f1;
    --color-secondary-hover: #818cf8;
    --color-secondary-muted: rgba(99, 102, 241, 0.15);
    
    --color-danger: #ef4444;
    --color-danger-hover: #f87171;
    --color-danger-muted: rgba(239, 68, 68, 0.15);
    
    --color-warning: #f59e0b;
    --color-warning-hover: #fbbf24;
    
    --color-success: #22c55e;
    --color-success-hover: #4ade80;
    
    --color-text: #e8ebf0;
    --color-text-secondary: #9aa4b2;
    --color-text-muted: #6b7280;
    
    /* Glassmorphism */
    --glass-bg: rgba(30, 35, 42, 0.7);
    --glass-border: rgba(61, 70, 86, 0.5);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    
    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;
    --space-2xl: 48px;
    
    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 12px;
    --font-size-sm: 14px;
    --font-size-base: 16px;
    --font-size-lg: 18px;
    --font-size-xl: 20px;
    --font-size-2xl: 28px;
    --font-size-3xl: 36px;
    
    /* Z-index */
    --z-dropdown: 100;
    --z-modal: 200;
    --z-toast: 300;
    --z-scanner: 400;
}

/* Reset */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
}

/* ========================================
   Layout
   ======================================== */

.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    max-width: 100%;
    overflow-x: hidden;
}

.main-content {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-lg);
    width: 100%;
    max-width: 480px;
    margin: 0 auto;
}

/* ========================================
   Header & Footer
   ======================================== */

.header {
    padding: var(--space-xl) var(--space-lg) var(--space-lg);
    text-align: center;
}

.header-content {
    max-width: 480px;
    margin: 0 auto;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--space-xs);
}

.logo svg {
    flex-shrink: 0;
}

.tagline {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    font-weight: 400;
}

.footer {
    padding: var(--space-lg);
    text-align: center;
    border-top: 1px solid var(--color-border);
    margin-top: auto;
}

.footer p {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

/* ========================================
   Screens
   ======================================== */

.screen {
    display: none;
    width: 100%;
    animation: fadeIn var(--transition-normal);
}

.screen.active {
    display: block;
}

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

/* ========================================
   Glass Card
   ======================================== */

.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    box-shadow: var(--glass-shadow);
}

/* ========================================
   Typography
   ======================================== */

h1, h2, h3, h4 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-text);
}

h2 { font-size: var(--font-size-xl); }
h3 { font-size: var(--font-size-lg); }

p { color: var(--color-text-secondary); }

/* ========================================
   Buttons
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    font-family: inherit;
    font-size: var(--font-size-sm);
    font-weight: 500;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    white-space: nowrap;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 212, 170, 0.3);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

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

.btn-secondary:hover:not(:disabled) {
    background: var(--color-surface-hover);
    border-color: var(--color-border-light);
}

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

.btn-danger:hover:not(:disabled) {
    background: var(--color-danger-hover);
}

.btn-block {
    width: 100%;
}

.btn-sm {
    padding: var(--space-xs) var(--space-md);
    font-size: var(--font-size-xs);
    gap: var(--space-xs);
}

.btn-back {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    padding: 0;
    background: transparent;
    border: none;
    border-radius: var(--radius-full);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-back:hover {
    background: var(--color-surface);
    color: var(--color-text);
}

.btn-copy {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-md);
    font-size: var(--font-size-xs);
    background: var(--color-surface);
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-copy:hover {
    background: var(--color-surface-hover);
    color: var(--color-text);
    border-color: var(--color-border-light);
}

.btn-close {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    color: var(--color-text-muted);
    font-size: var(--font-size-xl);
    cursor: pointer;
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

.btn-close:hover {
    background: var(--color-surface);
    color: var(--color-text);
}

/* ========================================
   Form Elements
   ======================================== */

input[type="text"],
input[type="file"] {
    font-family: inherit;
    font-size: var(--font-size-base);
}

input[type="text"] {
    width: 100%;
    padding: var(--space-md);
    background: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

input[type="text"]:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-muted);
}

input[type="text"]::placeholder {
    color: var(--color-text-muted);
    letter-spacing: 0.3em;
}

input[type="file"] {
    display: none;
}

/* ========================================
   Utility Classes
   ======================================== */

.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }

.text-center { text-align: center; }
.text-primary { color: var(--color-primary); }
.text-success { color: var(--color-success); }
.text-danger { color: var(--color-danger); }
.text-warning { color: var(--color-warning); }
.text-muted { color: var(--color-text-muted); }
.text-secondary { color: var(--color-text-secondary); }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }

/* ========================================
   Status Dots
   ======================================== */

.status-dot {
    display: inline-block;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--color-text-muted);
    transition: background var(--transition-fast);
}

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

.status-dot.connecting {
    background: var(--color-warning);
    animation: pulse 1.5s ease-in-out infinite;
}

.status-dot.disconnected {
    background: var(--color-danger);
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}

/* ========================================
   Scrollbar
   ======================================== */

::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-border-light);
}

/* ========================================
   Responsive
   ======================================== */

@media (max-width: 480px) {
    :root {
        --space-xl: 32px;
        --font-size-2xl: 24px;
        --font-size-xl: 18px;
    }
    
    .main-content {
        padding: var(--space-md);
        align-items: flex-start;
        min-height: calc(100vh - 120px);
    }
    
    .header {
        padding: var(--space-lg) var(--space-md) var(--space-md);
    }
}