/* === CSS CUSTOM PROPERTIES (shared palette with IdeaScratch) === */
:root {
    --color-primary: #1d4ed8;
    --color-primary-hover: #1e40af;
    --color-connect: #0ea5e9;
    --color-connect-hover: #0284c7;
    --color-success: #10b981;
    --color-error: #ef4444;
    --color-warning: #f59e0b;
    --color-text: #374151;
    --color-text-light: #6b7280;
    --color-text-muted: #9ca3af;
    --color-link: #2563eb;
    --color-bg: #f5f5f5;
    --color-bg-white: #ffffff;
    --color-bg-light: #f3f4f6;
    --color-border: #e5e7eb;
    --color-gray-disconnect: #6c757d;
    --radius-sm: 4px;
    --radius-md: 8px;
    --header-height: 52px;
}

* { box-sizing: border-box; }

/* The `hidden` attribute must beat author `display:` rules (e.g. flex rows
   toggled by learning mode), which otherwise override the UA default. */
[hidden] { display: none !important; }

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    background: var(--color-bg);
    color: var(--color-text);
    height: 100vh;
    display: flex;
    flex-direction: column;
}

/* === TITLE BAR === */
.titlebar {
    height: var(--header-height);
    background: var(--color-primary);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    flex: 0 0 auto;
}
.titlebar-left { display: flex; align-items: baseline; gap: 12px; }
.logo { font-size: 22px; font-weight: 700; letter-spacing: 0.5px; }
.subtitle { font-size: 13px; opacity: 0.85; }
.titlebar-right { display: flex; align-items: center; gap: 12px; }
.status-label { font-size: 13px; opacity: 0.9; }
#langBtn {
    font-size: 12px;
    font-weight: 600;
    padding: 5px 11px;
    background: rgba(255,255,255,0.1);
    color: #fff;
    border: 1px solid rgba(255,255,255,0.35);
}
#langBtn:hover:not(:disabled) { background: rgba(255,255,255,0.25); }

/* === LAYOUT === */
.layout {
    flex: 1;
    display: grid;
    grid-template-columns: minmax(320px, 1fr) minmax(420px, 1.4fr);
    gap: 16px;
    padding: 16px;
    overflow: auto;
}
.panel {
    background: var(--color-bg-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 16px;
}
.panel h2 {
    font-size: 16px;
    margin: 0 0 8px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px; height: 22px;
    background: var(--color-primary);
    color: #fff;
    border-radius: 50%;
    font-size: 13px;
}
.hint { color: var(--color-text-light); font-size: 13px; margin: 6px 0; }
hr { border: none; border-top: 1px solid var(--color-border); margin: 18px 0; }

/* === BUTTONS === */
.btn {
    border: 1px solid var(--color-border);
    background: var(--color-bg-white);
    color: var(--color-text);
    padding: 7px 14px;
    border-radius: var(--radius-md);
    font-size: 14px;
    cursor: pointer;
}
.btn:hover:not(:disabled) { background: var(--color-bg-light); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-primary { background: var(--color-primary); color: #fff; border-color: var(--color-primary); }
.btn-primary:hover:not(:disabled) { background: var(--color-primary-hover); }
.btn-connect { background: var(--color-connect); color: #fff; border-color: var(--color-connect); }
.btn-connect:hover:not(:disabled) { background: var(--color-connect-hover); }
.btn-connect.connected { background: var(--color-gray-disconnect); border-color: var(--color-gray-disconnect); }
.btn-ghost { border: none; color: var(--color-error); }
.btn-sm { padding: 4px 10px; font-size: 13px; }

/* === CLASS LIST === */
.class-list { display: flex; flex-direction: column; gap: 10px; margin: 12px 0; }
.class-card {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 10px 12px;
}
.class-card-head { display: flex; align-items: center; gap: 8px; cursor: pointer; }
.class-caret { color: var(--color-text-light); font-size: 12px; width: 12px; flex: 0 0 auto; }
.class-name { font-weight: 600; flex: 1; }
.class-count { color: var(--color-text-light); font-size: 13px; }

/* Sample thumbnails (shown when a class is expanded) */
.sample-grid { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.sample-thumb { position: relative; }
.sample-thumb canvas { background: #0f172a; border-radius: 4px; display: block; }
.sample-idx { position: absolute; bottom: 2px; left: 4px; font-size: 10px; color: rgba(255, 255, 255, 0.55); }
.sample-del {
    position: absolute; top: 2px; right: 2px;
    width: 16px; height: 16px; padding: 0; line-height: 14px;
    border: none; border-radius: 3px;
    background: rgba(239, 68, 68, 0.85); color: #fff;
    font-size: 11px; cursor: pointer;
}
.sample-del:hover { background: var(--color-error); }
.class-card-actions { display: flex; gap: 6px; }
.class-icon-row { display: flex; align-items: center; gap: 8px; margin: 8px 0; }
.icon-preview { background: #0f172a; border-radius: 3px; display: block; flex: 0 0 auto; }
.icon-select { padding: 4px 6px; border: 1px solid var(--color-border); border-radius: var(--radius-md); font-size: 13px; }
.mode-row { display: flex; align-items: center; gap: 8px; margin: 8px 0; }
.mode-row label { font-size: 13px; color: var(--color-text-light); }
.mode-row select { flex: 1; padding: 6px 8px; border: 1px solid var(--color-border); border-radius: var(--radius-md); font-size: 13px; }
.k-row { display: flex; align-items: center; gap: 8px; margin: 8px 0; }
.k-row label { font-size: 13px; color: var(--color-text-light); }
.k-row input { width: 64px; padding: 6px 8px; border: 1px solid var(--color-border); border-radius: var(--radius-md); font-size: 13px; }
.cluster-list { display: flex; flex-direction: column; gap: 8px; margin-top: 10px; }
.cluster-card { display: flex; align-items: center; gap: 8px; padding: 8px; border: 1px solid var(--color-border); border-radius: var(--radius-md); }
.cluster-name { flex: 1; min-width: 0; padding: 6px 8px; border: 1px solid var(--color-border); border-radius: var(--radius-md); font-size: 14px; }
.add-class-row { display: flex; gap: 8px; margin-top: 8px; }
.add-class-row input { flex: 1; padding: 7px 10px; border: 1px solid var(--color-border); border-radius: var(--radius-md); font-size: 14px; }
.data-footer { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-top: 14px; }
.data-footer-actions { display: flex; align-items: center; gap: 8px; }
.recording { outline: 2px solid var(--color-error); }

/* === LIVE CHART === */
#liveChart, #liveChartGyro {
    width: 100%;
    height: 120px;
    background: #0f172a;
    border-radius: var(--radius-md);
    display: block;
}
.chart-label { font-size: 12px; color: var(--color-text-light); margin: 10px 0 3px; }
.readout { font-family: ui-monospace, monospace; font-size: 14px; margin-top: 6px; }

/* === PREDICTIONS === */
.prediction-bars { display: flex; flex-direction: column; gap: 6px; }
.pred-row { display: flex; align-items: center; gap: 8px; }
.pred-icon { background: #0f172a; border-radius: 3px; flex: 0 0 auto; display: block; }
.pred-label { width: 96px; font-size: 13px; text-align: right; }
.pred-track { flex: 1; background: var(--color-bg-light); border-radius: 4px; height: 16px; overflow: hidden; }
.pred-fill { height: 100%; background: var(--color-success); width: 0%; transition: width 0.1s; }
.pred-row.top .pred-fill { background: var(--color-primary); }

/* === EXPORT === */
.export-row { display: flex; gap: 8px; margin: 8px 0; }
.code-preview { margin-top: 8px; }
.code-preview pre {
    background: #1a1a1a;
    color: #34d399;
    padding: 12px;
    border-radius: var(--radius-md);
    overflow: auto;
    max-height: 320px;
    font-size: 12px;
}

/* === Modals === */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 10000;
    align-items: center;
    justify-content: center;
}
.modal-box {
    border-radius: var(--radius-md);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}
.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 16px;
}
.modal-close-btn {
    background: none;
    border: none;
    font-size: 20px;
    cursor: pointer;
    line-height: 1;
}

/* Firmware Modal */
.fw-modal-box {
    background: #1e2430;
    border: 1px solid #374151;
    width: 500px;
    max-width: 90vw;
}
.fw-modal-box .modal-header {
    border-bottom: 1px solid #374151;
}
.fw-modal-box .modal-header span {
    color: #f9fafb;
    font-weight: bold;
    font-size: 14px;
}
.fw-modal-box .modal-close-btn {
    color: var(--color-text-light);
}
.fw-modal-body {
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.fw-warning-box {
    background: #7f1d1d;
    border: 1px solid var(--color-error);
    border-radius: var(--radius-sm);
    padding: 8px 12px;
    color: #fca5a5;
    font-size: 13px;
    font-weight: 600;
}
.fw-instructions {
    color: var(--color-text-muted);
    font-size: 13px;
    line-height: 1.6;
}
.fw-instructions strong {
    color: #f9fafb;
}
.fw-label {
    color: var(--color-text-muted);
    font-size: 12px;
    display: block;
    margin-bottom: 4px;
}
#firmwareSelect {
    width: 100%;
    padding: 6px 8px;
    background: #111827;
    color: #f9fafb;
    border: 1px solid #374151;
    border-radius: var(--radius-sm);
    font-size: 13px;
}
#firmwareFlashBtn {
    padding: 8px 16px;
    background: var(--color-link);
    color: #fff;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 13px;
    cursor: pointer;
    font-weight: 600;
}
#firmwareLog {
    background: #111827;
    border: 1px solid #374151;
    border-radius: var(--radius-sm);
    padding: 10px;
    font-family: monospace;
    font-size: 12px;
    height: 160px;
    overflow-y: auto;
    color: #d1d5db;
}

/* Help Modal */
.help-modal-box {
    background: var(--color-bg-white);
    border: 1px solid var(--color-border);
    width: 800px;
    max-width: 92vw;
    height: 560px;
    max-height: 85vh;
}
.help-modal-box .modal-header {
    border-bottom: 1px solid var(--color-border);
    background: var(--color-primary);
}
.help-modal-box .modal-header span {
    color: #fff;
    font-weight: bold;
    font-size: 14px;
}
.help-modal-box .modal-close-btn {
    color: rgba(255,255,255,0.8);
}
.help-modal-body {
    display: flex;
    flex: 1;
    min-height: 0;
}
#helpNav {
    width: 180px;
    flex-shrink: 0;
    border-right: 1px solid var(--color-border);
    overflow-y: auto;
    padding: 8px 0;
    background: #f9fafb;
}
.help-nav-item {
    padding: 9px 16px; font-size: 0.85em; color: #4b5563; cursor: pointer;
    border-left: 3px solid transparent;
}
.help-nav-item:hover { background: #f3f4f6; color: #111827; }
.help-nav-item.active { background: #eff6ff; color: #1d4ed8; font-weight: 600; border-left-color: #1d4ed8; }
#helpContent {
    flex: 1;
    overflow-y: auto;
    padding: 20px 24px;
    font-size: 13px;
    color: var(--color-text);
    line-height: 1.6;
}
#helpContent h3 { margin: 0 0 12px; font-size: 1.1em; color: #111827; }
#helpContent h4 { margin: 16px 0 6px; font-size: 0.9em; color: #374151; font-weight: 700; }
#helpContent p, #helpContent li { margin: 4px 0; }
#helpContent ul, #helpContent ol { padding-left: 20px; }
#helpContent a { color: #2563eb; text-decoration: none; }
#helpContent a:hover { text-decoration: underline; }
#helpContent code { background: #f3f4f6; padding: 1px 5px; border-radius: 3px; font-size: 0.9em; }
.help-warning {
    background: #fff7ed; border: 1px solid #fb923c; border-radius: var(--radius-sm);
    padding: 8px 12px; color: #9a3412; font-size: 0.9em;
}
.about-logos {
    display: flex; align-items: center; gap: 28px; flex-wrap: wrap;
    margin-top: 20px; padding-top: 16px; border-top: 1px solid var(--color-border);
}
.about-logos img { height: 44px; width: auto; display: block; }