:root {
    --primary: #4F46E5;
    --primary-hover: #4338CA;
    --bg: #F3F4F6;
    --surface: #FFFFFF;
    --text: #1F2937;
    --text-light: #6B7280;
    --border: #E5E7EB;
    --success: #10B981;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

body {
    background-color: var(--bg);
    color: var(--text);
    display: flex;
    justify-content: center;
    min-height: 100vh;
}

.app-container {
    width: 100%;
    max-width: 480px;
    background-color: var(--surface);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    height: 100vh;
}

@media (min-width: 480px) {
    .app-container {
        height: auto;
        min-height: 600px;
        margin-top: 2rem;
        border-radius: 1rem;
        overflow: hidden;
    }
}

header {
    background-color: var(--primary);
    color: white;
    padding: 1.5rem;
    text-align: center;
}

header h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.tabs {
    display: flex;
    border-bottom: 1px solid var(--border);
}

.tab-btn {
    flex: 1;
    padding: 1rem;
    background: none;
    border: none;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-light);
    cursor: pointer;
    transition: all 0.2s;
    border-bottom: 2px solid transparent;
}

.tab-btn.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
}

main {
    flex: 1;
    padding: 1.5rem;
    overflow-y: auto;
}

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.card h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text);
}

.input-group {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

input[type="text"] {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
    width: 100%;
}

input[type="text"]:focus {
    border-color: var(--primary);
}

button {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}

.primary-btn, #connect-btn {
    background-color: var(--primary);
    color: white;
}

.primary-btn:hover, #connect-btn:hover {
    background-color: var(--primary-hover);
}

.primary-btn:disabled, #connect-btn:disabled {
    background-color: var(--text-light);
    cursor: not-allowed;
}

.status-text {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-bottom: 1rem;
    text-align: center;
}

.hidden {
    display: none !important;
}

.file-label {
    display: block;
    width: 100%;
    padding: 2rem;
    border: 2px dashed var(--border);
    border-radius: 0.75rem;
    text-align: center;
    color: var(--text-light);
    cursor: pointer;
    transition: all 0.2s;
    margin-bottom: 1rem;
}

.file-label:hover {
    border-color: var(--primary);
    color: var(--primary);
    background-color: #EEF2FF;
}

.progress-container {
    margin-top: 1.5rem;
}

.progress-bar {
    width: 100%;
    height: 0.5rem;
    background-color: var(--border);
    border-radius: 999px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-fill {
    height: 100%;
    background-color: var(--success);
    width: 0%;
    transition: width 0.1s linear;
}

.progress-text {
    text-align: right;
    font-size: 0.875rem;
    color: var(--text-light);
}

/* New Styles for Multiple Files & QR */
.file-list {
    list-style: none;
    margin-top: 1rem;
    max-height: 200px;
    overflow-y: auto;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem;
    background: var(--bg);
    border-radius: 0.5rem;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    border: 1px solid var(--border);
}

.divider {
    display: flex;
    align-items: center;
    text-align: center;
    margin: 1.5rem 0;
    color: var(--text-light);
}

.divider::before, .divider::after {
    content: '';
    flex: 1;
    border-bottom: 1px solid var(--border);
}

.divider span {
    padding: 0 1rem;
    font-size: 0.875rem;
    font-weight: 500;
}

#qr-canvas {
    margin: 1rem auto;
    border: 8px solid white;
    border-radius: 0.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    max-width: 100%;
}

.action-buttons {
    display: flex;
    gap: 0.5rem;
}

.action-btn {
    padding: 0.4rem 0.8rem;
    font-size: 0.75rem;
    border-radius: 0.25rem;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}