:root {
    --bg-main: #f0f2f5;
    --bg-card: #ffffff;
    --bg-header: #f8fafc;
    --border-color: #e2e8f0;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --accent-blue: #0284c7;
    --accent-blue-hover: #0369a1;
    --accent-success: #16a34a;
    --accent-danger: #dc2626;
    --accent-purple: #7c3aed;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.08), 0 2px 4px -1px rgba(0,0,0,0.04);
}

body.dark {
    --bg-main: #0f172a;
    --bg-card: #1e293b;
    --bg-header: #182234;
    --border-color: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.4);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.4);
}

* {
    box-sizing: border-box;
}

body {
    /* Multiplatform font stack: macOS SF Pro / Windows Segoe UI / Linux Ubuntu / FreeSans fallback */
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    padding: 16px 24px;
    margin: 0;
    transition: background-color 0.25s ease, color 0.25s ease;
    -webkit-font-smoothing: antialiased;
}

/* Header & Top Bar */
.header-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 14px;
    padding: 12px 18px;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
}

.title-group {
    display: flex;
    align-items: center;
    gap: 12px;
}

.app-logo {
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.title-group h2 {
    margin: 0;
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--text-primary);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

/* Section Header */
.section-header {
    font-size: 0.82rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.6px;
    color: var(--text-secondary);
    margin: 14px 2px 6px 2px;
}

/* Controls Container */
.controls {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
    background-color: var(--bg-card);
    padding: 12px 16px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.full-width {
    width: 100%;
    display: block;
}

/* Divided Settings Grid - All boxes on one single row */
.settings-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-bottom: 12px;
}

@media (max-width: 900px) {
    .settings-grid {
        grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    }
}

.settings-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.settings-card-header {
    background-color: var(--bg-header);
    border-bottom: 1px solid var(--border-color);
    padding: 8px 12px;
}

.settings-card-title {
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--text-primary);
    text-transform: uppercase;
    letter-spacing: 0.4px;
}

.settings-card-body {
    padding: 10px 12px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px;
}

.form-group {
    display: flex;
    align-items: center;
    gap: 6px;
}

.form-group label {
    font-weight: 600;
    font-size: 0.82rem;
    color: var(--text-secondary);
    white-space: nowrap;
}

.controls select,
.controls input[type="number"],
.controls input[type="text"],
.settings-card select,
.settings-card input[type="number"],
.settings-card input[type="text"] {
    padding: 5px 8px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--bg-header);
    color: var(--text-primary);
    font-size: 0.85rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.controls select:focus,
.controls input:focus,
.settings-card select:focus,
.settings-card input:focus {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.2);
}

/* Buttons */
button {
    height: 34px;
    padding: 0 14px;
    font-size: 0.84rem;
    font-weight: 600;
    line-height: 32px;
    border: 1px solid transparent;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.15s ease, border-color 0.15s ease, transform 0.1s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    user-select: none;
    box-sizing: border-box;
}

button:active {
    transform: scale(0.98);
}

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

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

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

.btn-secondary:hover {
    background-color: var(--border-color);
}

.btn-secondary.active {
    background-color: var(--accent-blue);
    color: white;
    border-color: var(--accent-blue);
}

.btn-secondary.active:hover {
    background-color: var(--accent-blue-hover);
    color: white;
    border-color: var(--accent-blue-hover);
}

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

.btn-accent:hover {
    background-color: #6d28d9;
    border-color: #6d28d9;
}

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

.btn-success:hover {
    background-color: #15803d;
    border-color: #15803d;
}

button:disabled {
    background-color: var(--border-color) !important;
    border-color: var(--border-color) !important;
    color: var(--text-secondary) !important;
    cursor: not-allowed;
    opacity: 0.6;
}

/* Status Indicators */
.status-group {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 8px;
}

#status {
    padding: 4px 10px;
    border-radius: 6px;
    font-weight: 700;
    font-size: 0.78rem;
    letter-spacing: 0.3px;
    color: white;
    text-transform: uppercase;
}

.connected { background-color: var(--accent-success); }
.disconnected { background-color: var(--accent-danger); }
.demo-mode { background-color: #d97706 !important; }

.rate-badge {
    background-color: var(--bg-header);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-weight: 700;
    font-size: 0.78rem;
    padding: 4px 8px;
    border-radius: 6px;
}

/* Channel Configuration Cards */
.channel-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
}

.channel-card {
    background: var(--bg-header);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.channel-card:hover {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 1px var(--accent-blue);
}

.ch-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 10px;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
}

.ch-name-input {
    background: transparent;
    border: none;
    font-weight: 700;
    font-size: 0.85rem;
    width: 90px;
    color: var(--text-primary);
    border-bottom: 1px dashed transparent;
}

.ch-name-input:focus {
    outline: none;
    border-bottom: 1px solid var(--accent-blue);
}

.ch-body {
    padding: 8px 10px;
    font-size: 0.78rem;
}

.ch-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 6px;
}

.ch-color {
    border: none;
    width: 26px;
    height: 22px;
    cursor: pointer;
    background: transparent;
    padding: 0;
}

.stats-box div {
    display: flex;
    justify-content: space-between;
    margin-bottom: 2px;
    color: var(--text-secondary);
}

.stats-box span:last-child {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-weight: 700;
    color: var(--text-primary);
}

.peak-stat {
    border-top: 1px dashed var(--border-color);
    padding-top: 3px;
    margin-top: 3px;
}

.highlight-stat {
    color: var(--accent-blue) !important;
}

/* Graph View Toolbar (Positioned directly over the graph) */
.graph-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 8px 14px;
    margin-top: 16px;
    margin-bottom: 8px;
    box-shadow: var(--shadow-sm);
}

.graph-toolbar-left {
    display: flex;
    align-items: center;
    gap: 10px;
}

.toolbar-label {
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.view-toggle-group {
    display: flex;
    background: var(--bg-header);
    border: 1px solid var(--border-color);
    border-radius: 7px;
    padding: 2px;
    gap: 2px;
}

.view-btn {
    background: transparent;
    color: var(--text-secondary);
    border: none;
    padding: 5px 12px;
    font-size: 0.82rem;
    font-weight: 600;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.15s ease;
}

.view-btn:hover {
    color: var(--text-primary);
    background-color: rgba(0, 0, 0, 0.05);
}

.view-btn.active {
    background-color: var(--accent-blue);
    color: white;
    box-shadow: 0 1px 2px rgba(0,0,0,0.15);
}

.graph-toolbar-right {
    display: flex;
    align-items: center;
    gap: 10px;
}

.rate-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 80px;
    width: 80px;
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-variant-numeric: tabular-nums;
    font-weight: 700;
    font-size: 0.82rem;
    color: var(--text-secondary);
    background-color: var(--bg-header);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 6px 10px;
    text-align: center;
    box-sizing: border-box;
    white-space: nowrap;
}

.fullscreen-btn {
    font-size: 0.82rem;
    padding: 5px 12px;
}

/* Plots Layout */
.plots-layout {
    display: grid;
    gap: 14px;
    margin-bottom: 24px;
}

.split-layout {
    grid-template-columns: 1fr 1fr;
}

.time-layout {
    grid-template-columns: 1fr;
}

.fft-layout {
    grid-template-columns: 1fr;
}

@media (max-width: 992px) {
    .split-layout {
        grid-template-columns: 1fr;
    }
}

.canvas-panel {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 12px;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
    padding-bottom: 6px;
    border-bottom: 1px solid var(--border-color);
}

.panel-title {
    font-size: 0.88rem;
    font-weight: 700;
    color: var(--text-primary);
}

.panel-subtitle {
    font-size: 0.76rem;
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    color: var(--text-secondary);
}

.canvas-wrapper {
    position: relative;
    height: 380px;
    width: 100%;
    resize: vertical;
    overflow: hidden;
    min-height: 220px;
}

.canvas-wrapper canvas {
    width: 100% !important;
    height: 100% !important;
}

/* Fullscreen Mode */
.plots-layout:fullscreen {
    background-color: var(--bg-main);
    padding: 20px;
    overflow-y: auto;
}

/* Dark Mode Switch */
.toggle-container {
    display: flex;
    align-items: center;
    gap: 8px;
}

#modeLabel {
    font-size: 0.82rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.switch { position: relative; display: inline-block; width: 36px; height: 18px; }
.switch input { opacity: 0; width: 0; height: 0; }
.slider { position: absolute; cursor: pointer; top: 0; left: 0; right: 0; bottom: 0; background-color: var(--border-color); transition: .3s; border-radius: 34px; }
.slider:before { position: absolute; content: ""; height: 14px; width: 14px; left: 2px; bottom: 2px; background-color: white; transition: .3s; border-radius: 50%; }
input:checked + .slider { background-color: var(--accent-blue); }
input:checked + .slider:before { transform: translateX(18px); }

/* Terminal Component */
.terminal-section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.terminal-header-tools {
    display: flex;
    gap: 8px;
}

.btn-xs {
    padding: 3px 8px;
    font-size: 0.76rem;
}

.terminal-panel {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.terminal-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--bg-header);
    padding: 6px 12px;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.8rem;
}

.terminal-status-info {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    color: var(--text-secondary);
}

.terminal-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: inline-block;
}

.terminal-indicator.connected {
    background-color: var(--accent-success);
    box-shadow: 0 0 6px rgba(22, 163, 74, 0.6);
}

.terminal-indicator.disconnected {
    background-color: var(--accent-danger);
}

.terminal-indicator.demo-mode {
    background-color: #d97706;
}

.terminal-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.terminal-checkbox-label {
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 0.78rem;
    color: var(--text-secondary);
    cursor: pointer;
}

.terminal-output {
    background-color: #0b1120;
    color: #e2e8f0;
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
    font-size: 0.82rem;
    line-height: 1.45;
    padding: 10px 12px;
    height: 180px;
    overflow-y: auto;
    white-space: pre-wrap;
    word-break: break-all;
    border-bottom: 1px solid var(--border-color);
}

body.dark .terminal-output {
    background-color: #050b14;
    color: #f1f5f9;
}

.term-line {
    margin-bottom: 2px;
}

.term-time {
    color: #64748b;
    margin-right: 6px;
    font-size: 0.76rem;
}

.term-tx {
    color: #38bdf8;
}

.term-rx {
    color: #4ade80;
}

.term-info {
    color: #fbbf24;
}

.term-err {
    color: #f87171;
}

.term-tag-tx {
    font-weight: 700;
    color: #38bdf8;
    margin-right: 4px;
}

.term-tag-rx {
    font-weight: 700;
    color: #4ade80;
    margin-right: 4px;
}

.terminal-input-bar {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background-color: var(--bg-card);
}

.terminal-input-field {
    flex: 1;
    padding: 6px 10px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--bg-header);
    color: var(--text-primary);
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-size: 0.84rem;
    outline: none;
}

.terminal-input-field:focus {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.2);
}