:root {
    --bg-color: #f0f4f8;
    --card-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #cbd5e1;
    --input-bg: #ffffff;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --focus-border: #64748b;
    --focus-ring: rgba(100, 116, 139, 0.4);
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --error-color: #ef4444;
    --error-hover: #dc2626;
    --success-color: #10b981;
    --success-hover: #059669;
    --warning-color: #f59e0b;
    --warning-hover: #d97706;
    --transition: all 0.2s ease;
}

[data-theme="dark"] {
    --bg-color: #31353a;
    --card-bg: #26292d;
    --text-main: #f8fafc;
    --text-muted: #9ba1a6;
    --border-color: #4a5057;
    --input-bg: #1e2124;
    --primary: #60a5fa;
    --primary-hover: #93c5fd;
    --focus-border: #9ba1a6;
    --focus-ring: rgba(155, 161, 166, 0.4);
    --shadow-md: 0 8px 12px -3px rgb(0 0 0 / 0.3);
    --error-color: #f87171;
    --error-hover: #ef4444;
    --success-color: #34d399;
    --success-hover: #10b981;
    --warning-color: #fbbf24;
    --warning-hover: #f59e0b;
}

* {
    box-sizing: border-box;
    font-family: 'JetBrains Mono', monospace;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    padding: 1.5rem;
    margin: 0;
    transition: var(--transition);
    font-size: 16px;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.25rem;
}

h1 {
    font-size: 1.75rem;
    font-weight: 700;
    margin: 0;
}

.theme-control {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.theme-label {
    font-size: 0.9rem;
    font-weight: 500;
}

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

.theme-switch {
    position: relative;
    width: 50px;
    height: 28px;
    background-color: var(--border-color);
    border-radius: 999px;
    cursor: pointer;
    transition: var(--transition);
}

.theme-switch:focus {
    outline: none;
    box-shadow: 0 0 0 3px var(--focus-ring);
}

.toggle-thumb {
    position: absolute;
    top: 3px;
    left: 3px;
    width: 22px;
    height: 22px;
    background-color: white;
    border-radius: 50%;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
}

#darkModeToggle:checked + .theme-switch {
    background-color: var(--primary);
}

#darkModeToggle:checked + .theme-switch .toggle-thumb {
    transform: translateX(22px);
}

.main-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 1.25rem;
}

@media (min-width: 768px) {
    .main-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
    .full-width {
        grid-column: 1 / -1;
    }
}

.card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.card h2 {
    margin-top: 0;
    margin-bottom: 1.25rem;
    font-size: 1.2rem;
    color: var(--text-main);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    min-width: 0;
}

.input-wrapper {
    display: flex;
    flex-direction: column;
    flex: 1;
    position: relative;
    min-width: 0;
}

.input-with-btn {
    display: flex;
    gap: 0.75rem;
    align-items: flex-start;
    width: 100%;
}

.input-with-btn input {
    width: 100%;
}

button {
    background-color: var(--primary);
    color: #ffffff;
    border: none;
    padding: 0 1.5rem;
    border-radius: 6px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    outline: none;
    height: 38px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

button:hover:not(:disabled) {
    background-color: var(--primary-hover);
}

button:focus:not(:disabled) {
    box-shadow: 0 0 0 3px var(--focus-ring);
    outline: none;
}

button:disabled {
    background-color: var(--border-color);
    color: var(--text-muted);
    cursor: not-allowed;
}

label {
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--text-muted);
}

input[type="text"] {
    width: 100%;
    height: 38px;
    padding: 0.6rem 0.85rem;
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.95rem;
    color: var(--text-main);
    outline: none;
    transition: var(--transition);
}

input:focus {
    border-color: var(--focus-border);
    box-shadow: 0 0 0 3px var(--focus-ring);
    outline: none;
}

.error-msg {
    display: none;
    color: var(--error-color);
    font-size: 0.85rem;
    margin-top: 0.5rem;
    font-weight: 600;
}
.error-msg.active {
    display: block;
}

.status-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.3rem 0.75rem;
    border-radius: 99px;
    font-size: 0.8rem;
    font-weight: 700;
    background-color: var(--border-color);
    color: var(--text-main);
}
.status-badge.connected {
    background-color: rgba(16, 185, 129, 0.15);
    color: var(--success-color);
}
.status-badge.disconnected {
    background-color: rgba(239, 68, 68, 0.15);
    color: var(--error-color);
}
.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: currentColor;
}

.file-drop-area {
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    background-color: var(--input-bg);
    transition: var(--transition);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}
.file-drop-area:hover, .file-drop-area.dragover {
    border-color: var(--primary);
    background-color: rgba(59, 130, 246, 0.05);
}
.file-drop-text {
    font-weight: 600;
    color: var(--text-main);
}
.file-drop-subtext {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.log-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    max-height: 400px;
    overflow-y: auto;
}

.log-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9rem;
}

.log-info {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
    overflow: hidden;
}

.log-name {
    font-weight: 600;
    color: var(--text-main);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.log-meta {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.log-meta span.sent { color: var(--primary); font-weight: 600; }
.log-meta span.received { color: var(--success-color); font-weight: 600; }

.download-btn {
    height: 30px;
    padding: 0 1rem;
    font-size: 0.8rem;
    background-color: var(--success-color);
}
.download-btn:hover {
    background-color: var(--success-hover);
}

.placeholder-text {
    color: var(--text-muted);
    font-style: italic;
    text-align: center;
    padding: 1rem;
}