/* =========================================================================
   RAD 321 — Image Recording & Analysis
   Shared Lab Design System
   Used by every lab page, student handout, and teacher handout
   ========================================================================= */

:root {
  /* Core palette — clinical/radiology blue-teal, warm accent for alerts */
  --rad-navy: #0b2545;
  --rad-blue: #13315c;
  --rad-blue-light: #1d4e89;
  --rad-teal: #0e7c86;
  --rad-teal-light: #12a3b0;
  --rad-cyan: #4fd1c5;
  --rad-amber: #e8a33d;
  --rad-amber-dark: #b9781f;
  --rad-red: #c9432c;
  --rad-green: #2f9e5b;
  --rad-bg: #f4f7fb;
  --rad-bg-panel: #ffffff;
  --rad-bg-soft: #eef3f8;
  --rad-border: #d7e1ec;
  --rad-text: #1c2b3a;
  --rad-text-soft: #52667a;
  --rad-text-faint: #8598ac;
  --rad-shadow: 0 2px 10px rgba(11, 37, 69, 0.08);
  --rad-shadow-lg: 0 10px 30px rgba(11, 37, 69, 0.14);
  --rad-radius: 14px;
  --rad-radius-sm: 8px;
  --rad-maxw: 1180px;
  --font-main: 'Segoe UI', 'Inter', -apple-system, BlinkMacSystemFont, Roboto, Arial, sans-serif;
  --font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-main);
  color: var(--rad-text);
  background: var(--rad-bg);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

/* ---------------------------------------------------------------------- */
/* Top App Bar                                                            */
/* ---------------------------------------------------------------------- */
.lab-topbar {
  background: linear-gradient(120deg, var(--rad-navy) 0%, var(--rad-blue-light) 60%, var(--rad-teal) 130%);
  color: #fff;
  padding: 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--rad-shadow-lg);
}
.lab-topbar-inner {
  max-width: var(--rad-maxw);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.lab-brand { display: flex; align-items: center; gap: 12px; }
.lab-brand-badge {
  width: 42px; height: 42px; border-radius: 10px;
  background: rgba(255,255,255,0.12);
  display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 15px; letter-spacing: 0.5px;
  border: 1px solid rgba(255,255,255,0.25);
}
.lab-brand-text .lab-course { font-size: 12px; opacity: 0.8; letter-spacing: 1px; text-transform: uppercase; }
.lab-brand-text .lab-title { font-size: 18px; font-weight: 700; }
.lab-topbar-actions { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }

.mode-pill {
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(79, 209, 197, 0.18);
  border: 1px solid rgba(79, 209, 197, 0.55);
  color: #d2fbf5;
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 12.5px;
  font-weight: 600;
}

/* ---------------------------------------------------------------------- */
/* Layout                                                                 */
/* ---------------------------------------------------------------------- */
.lab-container { max-width: var(--rad-maxw); margin: 0 auto; padding: 28px 24px 80px; }

.lab-progress-wrap {
  max-width: var(--rad-maxw); margin: 0 auto; padding: 0 24px;
}
.lab-progress-track {
  height: 8px; background: var(--rad-border); border-radius: 999px; overflow: hidden; margin-top: 14px;
}
.lab-progress-fill {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--rad-teal), var(--rad-cyan));
  transition: width .4s ease;
}
.lab-progress-label { font-size: 12px; color: rgba(255,255,255,0.85); margin-top: 6px; display:flex; justify-content: space-between; }

/* Sticky nav of section chips */
.lab-nav {
  display: flex; gap: 8px; flex-wrap: wrap; padding: 14px 24px;
  max-width: var(--rad-maxw); margin: 0 auto;
  position: sticky; top: 78px; z-index: 90;
  background: rgba(244,247,251,0.92); backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--rad-border);
}
.lab-nav a {
  text-decoration: none; font-size: 13px; font-weight: 600; color: var(--rad-text-soft);
  background: #fff; border: 1px solid var(--rad-border); padding: 7px 13px; border-radius: 999px;
  transition: all .15s ease; white-space: nowrap;
}
.lab-nav a:hover { border-color: var(--rad-teal-light); color: var(--rad-teal); }
.lab-nav a.done { color: var(--rad-green); border-color: var(--rad-green); background: #eefaf1; }
.lab-nav a .chip-check { margin-right: 4px; }

/* Sections / cards */
.lab-section { margin: 42px 0; scroll-margin-top: 150px; }
.lab-section-head { display: flex; align-items: center; gap: 14px; margin-bottom: 18px; }
.lab-section-num {
  width: 38px; height: 38px; border-radius: 10px; flex-shrink: 0;
  background: var(--rad-navy); color: #fff; font-weight: 800; font-size: 15px;
  display: flex; align-items: center; justify-content: center;
}
.lab-section-head h2 { margin: 0; font-size: 21px; color: var(--rad-navy); }
.lab-section-head .lab-section-sub { font-size: 13px; color: var(--rad-text-faint); margin-top: 2px; }

.card {
  background: var(--rad-bg-panel);
  border: 1px solid var(--rad-border);
  border-radius: var(--rad-radius);
  box-shadow: var(--rad-shadow);
  padding: 24px;
  margin-bottom: 20px;
}
.card h3 { margin-top: 0; color: var(--rad-blue); font-size: 17px; }
.card h4 { color: var(--rad-blue); font-size: 15px; margin-bottom: 8px;}

.card-soft { background: var(--rad-bg-soft); border: 1px dashed var(--rad-border); }

.two-col { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 20px; }
.three-col { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
@media (max-width: 880px) {
  .two-col, .three-col { grid-template-columns: 1fr; }
}

/* Badges & labels */
.badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 11.5px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.4px;
  padding: 4px 10px; border-radius: 999px;
}
.badge-theory { background: #e7edfb; color: var(--rad-blue-light); }
.badge-sim { background: #e2f6f2; color: var(--rad-teal); }
.badge-check { background: #fdeee4; color: var(--rad-amber-dark); }
.badge-worksheet { background: #f1e9fb; color: #6b3fa0; }
.badge-rubric { background: #fbe7ea; color: var(--rad-red); }
.badge-objective { background: #eaf6ea; color: var(--rad-green); }

.highlight-note {
  display: flex; gap: 12px; align-items: flex-start;
  background: #eef3f8; border: 1px solid var(--rad-border); border-left: 4px solid var(--rad-teal);
  border-radius: var(--rad-radius-sm); padding: 14px 16px; margin: 14px 0; font-size: 14px;
}
.highlight-note .icon { font-size: 20px; }

.info-note {
  background: #eaf4fb; border-left: 4px solid var(--rad-blue-light);
  border-radius: var(--rad-radius-sm); padding: 14px 16px; margin: 14px 0; font-size: 14px;
}
.tip-note {
  background: #eafaf1; border-left: 4px solid var(--rad-green);
  border-radius: var(--rad-radius-sm); padding: 14px 16px; margin: 14px 0; font-size: 14px;
}

/* Objectives list */
.objectives-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.objectives-list li {
  display: flex; gap: 10px; align-items: flex-start;
  background: var(--rad-bg-soft); border-radius: var(--rad-radius-sm); padding: 10px 14px; font-size: 14.5px;
}
.objectives-list li .num {
  flex-shrink: 0; width: 22px; height: 22px; border-radius: 50%; background: var(--rad-teal); color: #fff;
  font-size: 12px; font-weight: 700; display: flex; align-items: center; justify-content: center; margin-top: 1px;
}

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: 8px; cursor: pointer;
  font-family: inherit; font-size: 14px; font-weight: 600;
  padding: 10px 18px; border-radius: 999px; border: 1px solid transparent;
  transition: all .15s ease; text-decoration: none;
}
.btn-primary { background: var(--rad-teal); color: #fff; }
.btn-primary:hover { background: var(--rad-teal-light); }
.btn-secondary { background: #fff; color: var(--rad-blue); border-color: var(--rad-border); }
.btn-secondary:hover { border-color: var(--rad-blue-light); }
.btn-ghost { background: transparent; color: rgba(255,255,255,0.9); border-color: rgba(255,255,255,0.4); }
.btn-ghost:hover { background: rgba(255,255,255,0.12); }
.btn-amber { background: var(--rad-amber); color: #3a2609; }
.btn-amber:hover { background: #f0ae4c; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-sm { padding: 6px 12px; font-size: 12.5px; }
.btn-block { width: 100%; justify-content: center; }

/* Form elements */
label.field-label { display: block; font-weight: 600; font-size: 13.5px; margin-bottom: 6px; color: var(--rad-blue); }
input[type=text], input[type=number], textarea, select {
  width: 100%; font-family: inherit; font-size: 14px; color: var(--rad-text);
  padding: 10px 12px; border-radius: var(--rad-radius-sm); border: 1px solid var(--rad-border);
  background: #fff; transition: border-color .15s ease;
}
input[type=text]:focus, input[type=number]:focus, textarea:focus, select:focus {
  outline: none; border-color: var(--rad-teal-light); box-shadow: 0 0 0 3px rgba(18,163,176,0.15);
}
textarea { resize: vertical; min-height: 80px; }
.form-row { margin-bottom: 16px; }
.form-hint { font-size: 12px; color: var(--rad-text-faint); margin-top: 4px; }

/* Sliders */
.slider-row { margin-bottom: 18px; }
.slider-row .slider-label {
  display: flex; justify-content: space-between; font-size: 13.5px; font-weight: 600; color: var(--rad-blue); margin-bottom: 6px;
}
.slider-row .slider-value {
  font-family: var(--font-mono); background: var(--rad-navy); color: #fff; padding: 2px 10px; border-radius: 6px; font-size: 12.5px;
}
input[type=range] {
  width: 100%; height: 6px; border-radius: 999px; background: var(--rad-border);
  -webkit-appearance: none; appearance: none; cursor: pointer;
}
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 20px; height: 20px; border-radius: 50%;
  background: var(--rad-teal); border: 3px solid #fff; box-shadow: 0 0 0 1px var(--rad-teal);
  cursor: pointer; margin-top: -7px;
}
input[type=range]::-moz-range-thumb {
  width: 20px; height: 20px; border-radius: 50%; background: var(--rad-teal); border: 3px solid #fff;
  box-shadow: 0 0 0 1px var(--rad-teal); cursor: pointer;
}
input[type=range]::-webkit-slider-runnable-track { height: 6px; border-radius: 999px; }

/* Tables */
table.data-table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
table.data-table th, table.data-table td {
  border: 1px solid var(--rad-border); padding: 9px 11px; text-align: left;
}
table.data-table th { background: var(--rad-bg-soft); color: var(--rad-blue); font-weight: 700; }
table.data-table tr:nth-child(even) td { background: #fafcfe; }

/* Quiz / MCQ */
.quiz-q { margin-bottom: 22px; padding-bottom: 18px; border-bottom: 1px dashed var(--rad-border); }
.quiz-q:last-child { border-bottom: none; }
.quiz-q .quiz-prompt { font-weight: 600; margin-bottom: 10px; font-size: 14.5px; }
.quiz-options { display: grid; gap: 8px; }
.quiz-option {
  display: flex; align-items: center; gap: 10px; padding: 9px 12px;
  border: 1px solid var(--rad-border); border-radius: var(--rad-radius-sm); cursor: pointer; font-size: 14px;
  background: #fff; transition: all .12s ease; width: 100%; text-align: left; color: var(--rad-text); font-family: inherit;
}
.quiz-option:hover { border-color: var(--rad-teal-light); }
.quiz-option.selected { border-color: var(--rad-teal); background: #eafaf8; }
.quiz-option.correct { border-color: var(--rad-green); background: #eafaf1; }
.quiz-option.incorrect { border-color: var(--rad-red); background: #fdecea; }
.quiz-feedback { font-size: 13px; margin-top: 8px; padding: 8px 12px; border-radius: 8px; display: none; }
.quiz-feedback.show { display: block; }
.quiz-feedback.correct { background: #eafaf1; color: var(--rad-green); }
.quiz-feedback.incorrect { background: #fdecea; color: var(--rad-red); }

/* Drag & drop ordering */
.dragzone { display: grid; gap: 10px; }
.drag-item {
  background: #fff; border: 2px solid var(--rad-border); border-radius: var(--rad-radius-sm);
  padding: 12px 14px; cursor: grab; display: flex; align-items: center; gap: 12px; font-size: 14px; font-weight: 600;
  color: var(--rad-blue); transition: all .12s ease;
}
.drag-item .drag-handle { color: var(--rad-text-faint); font-size: 18px; }
.drag-label { flex: 1; }
.drag-key-controls { display: inline-flex; gap: 4px; margin-left: auto; }
.drag-key-controls button { width: 30px; height: 30px; border: 1px solid var(--rad-border); border-radius: 7px; background: var(--rad-bg-soft); color: var(--rad-blue); cursor: pointer; }
.drag-key-controls button:disabled { opacity: .35; cursor: default; }
.drag-item.dragging { opacity: 0.5; }
.drag-item.correct-pos { border-color: var(--rad-green); background: #f2fbf5; }
.drag-item.incorrect-pos { border-color: var(--rad-red); background: #fdf2f1; }
.drop-target { min-height: 8px; }

/* Match pairs */
.match-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.match-col-title { font-size: 12.5px; text-transform: uppercase; letter-spacing: 0.5px; color: var(--rad-text-faint); margin-bottom: 8px; font-weight: 700; }
.match-item {
  padding: 10px 12px; border: 1px solid var(--rad-border); border-radius: var(--rad-radius-sm); margin-bottom: 8px;
  background: #fff; cursor: pointer; font-size: 13.5px; transition: all .12s ease; width: 100%; text-align: left; color: var(--rad-text); font-family: inherit;
}
.match-item.selected { border-color: var(--rad-teal); background: #eafaf8; }
.match-item.matched-correct { border-color: var(--rad-green); background: #eafaf1; cursor: default; }
.match-item.matched-incorrect { border-color: var(--rad-red); background: #fdecea; }

/* Hotspot / clickable diagram */
.hotspot-wrap { position: relative; display: inline-block; border-radius: var(--rad-radius-sm); overflow: hidden; border: 1px solid var(--rad-border); }
.hotspot-wrap img { position: relative; z-index: 1; width: 100%; height: auto; pointer-events: none; }
.hotspot {
  position: absolute; width: 26px; height: 26px; border-radius: 50%;
  background: rgba(232,163,61,0.85); border: 2px solid #fff; color: #fff; font-weight: 800; font-size: 13px;
  display: flex; align-items: center; justify-content: center; cursor: pointer;
  box-shadow: 0 0 0 4px rgba(232,163,61,0.25); transform: translate(-50%, -50%);
  transition: all .15s ease; animation: pulse 2.2s infinite; z-index: 2;
}
.hotspot.identified { background: rgba(47,158,91,0.9); box-shadow: 0 0 0 4px rgba(47,158,91,0.25); animation: none; }
@keyframes pulse { 0%,100% { box-shadow: 0 0 0 4px rgba(232,163,61,0.25);} 50% { box-shadow: 0 0 0 8px rgba(232,163,61,0.12);} }
.hotspot-caption { font-size: 13px; margin-top: 10px; color: var(--rad-text-soft); min-height: 20px; }

/* Simulated radiograph canvas frame */
.radiograph-frame {
  background: #05070a; border-radius: var(--rad-radius-sm); padding: 10px;
  display: flex; align-items: center; justify-content: center; border: 1px solid #000;
}
.radiograph-frame canvas { border-radius: 4px; display: block; }
.readout-strip {
  display: flex; gap: 14px; flex-wrap: wrap; margin-top: 12px; font-family: var(--font-mono); font-size: 12.5px;
}
.readout-chip {
  background: var(--rad-navy); color: #cdeff0; padding: 6px 12px; border-radius: 6px;
}
.readout-chip b { color: #fff; }

/* Rubric table */
.rubric-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.rubric-table th, .rubric-table td { border: 1px solid var(--rad-border); padding: 10px; vertical-align: top; }
.rubric-table th { background: var(--rad-navy); color: #fff; font-size: 12.5px; text-transform: uppercase; letter-spacing: 0.3px; }
.rubric-table td.crit-name { font-weight: 700; color: var(--rad-blue); width: 16%; }
.rubric-table td.crit-pts { text-align: center; font-weight: 700; width: 8%; color: var(--rad-teal); }
.rubric-score-input { width: 60px; padding: 6px; text-align: center; }
.rubric-total-row td { background: var(--rad-bg-soft); font-weight: 800; color: var(--rad-navy); }

/* Footer action bar (sticky) */
.lab-actionbar {
  position: sticky; bottom: 0; z-index: 95;
  background: #fff; border-top: 1px solid var(--rad-border);
  box-shadow: 0 -6px 20px rgba(11,37,69,0.08);
  padding: 14px 24px;
}
.lab-actionbar-inner {
  max-width: var(--rad-maxw); margin: 0 auto; display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap;
}
.autosave-indicator { font-size: 12.5px; color: var(--rad-text-faint); display: flex; align-items: center; gap: 6px; }
.autosave-indicator .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--rad-green); }

/* Handout-specific print styling */
.handout-page { max-width: 880px; margin: 0 auto; padding: 40px 32px; background: #fff; }
.handout-header { text-align: center; border-bottom: 3px solid var(--rad-navy); padding-bottom: 18px; margin-bottom: 26px; }
.handout-header .h-course { color: var(--rad-teal); font-weight: 700; letter-spacing: 1px; font-size: 13px; text-transform: uppercase; }
.handout-header h1 { color: var(--rad-navy); margin: 6px 0; font-size: 26px; }
.handout-meta { display: flex; justify-content: center; gap: 24px; font-size: 12.5px; color: var(--rad-text-faint); margin-top: 8px; flex-wrap: wrap;}
.handout-section { margin: 26px 0; }
.handout-section h2 { color: var(--rad-navy); font-size: 18px; border-left: 4px solid var(--rad-teal); padding-left: 10px; }
.print-btn-bar { text-align: center; margin: 20px 0; }
@media print {
  .no-print { display: none !important; }
  body { background: #fff; }
  .handout-page { padding: 0; max-width: 100%; }
  .card { box-shadow: none; }
}

/* Utility */
.muted { color: var(--rad-text-faint); }
.text-center { text-align: center; }
.mt-0 { margin-top: 0; } .mb-0 { margin-bottom: 0; }
.flex { display: flex; } .gap-8 { gap: 8px; } .gap-12 { gap: 12px; }
.items-center { align-items: center; } .justify-between { justify-content: space-between; }
.small { font-size: 12.5px; }
hr.divider { border: none; border-top: 1px solid var(--rad-border); margin: 24px 0; }

/* Footer */
.lab-footer {
  max-width: var(--rad-maxw); margin: 40px auto 0; padding: 20px 24px; text-align: center;
  color: var(--rad-text-faint); font-size: 12.5px; border-top: 1px solid var(--rad-border);
}

/* Toast */
#toast-container { position: fixed; top: 90px; right: 20px; z-index: 999; display: flex; flex-direction: column; gap: 10px; }
.toast {
  background: var(--rad-navy); color: #fff; padding: 12px 18px; border-radius: 10px; font-size: 13.5px;
  box-shadow: var(--rad-shadow-lg); opacity: 0; transform: translateX(20px); transition: all .3s ease;
}
.toast.show { opacity: 1; transform: translateX(0); }
.toast.success { background: var(--rad-green); }
.toast.error { background: var(--rad-red); }

/* Accessibility */
.sr-only {
  position: absolute !important; width: 1px !important; height: 1px !important;
  padding: 0 !important; margin: -1px !important; overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important; white-space: nowrap !important; border: 0 !important;
}
.skip-link {
  position: fixed; left: 16px; top: -80px; z-index: 2000; padding: 10px 16px;
  border-radius: 8px; background: var(--rad-navy); color: #fff; font-weight: 700;
}
.skip-link:focus { top: 12px; }
button:focus-visible, a:focus-visible, input:focus-visible, textarea:focus-visible, select:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid #f2b84b; outline-offset: 3px;
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; scroll-behavior: auto !important; }
}

/* ========================================================================= */
/* Reading Room Mode (Calibrated Dark Theme)                                 */
/* ========================================================================= */
[data-theme="dark"] {
  --rad-navy: #050e18;
  --rad-blue: #0c2038;
  --rad-blue-light: #16365c;
  --rad-teal: #14b8a6;
  --rad-teal-light: #2dd4bf;
  --rad-cyan: #67e8f9;
  --rad-bg: #090d13;
  --rad-bg-panel: #111822;
  --rad-bg-soft: #182230;
  --rad-border: #223246;
  --rad-text: #e2eaf2;
  --rad-text-soft: #9fb3c8;
  --rad-text-faint: #627d98;
  --rad-shadow: 0 4px 16px rgba(0, 0, 0, 0.45);
  --rad-shadow-lg: 0 10px 32px rgba(0, 0, 0, 0.65);
}

[data-theme="dark"] body {
  background: var(--rad-bg);
  color: var(--rad-text);
}

[data-theme="dark"] .card {
  background: var(--rad-bg-panel);
  border-color: var(--rad-border);
}

[data-theme="dark"] .card-soft,
[data-theme="dark"] .why-sim-card,
[data-theme="dark"] .control-card,
[data-theme="dark"] .metric,
[data-theme="dark"] .procedure-step,
[data-theme="dark"] .challenge-card,
[data-theme="dark"] .station-card,
[data-theme="dark"] .case-box,
[data-theme="dark"] .submission-check div {
  background: var(--rad-bg-soft);
  border-color: var(--rad-border);
  color: var(--rad-text);
}

[data-theme="dark"] .card h3,
[data-theme="dark"] .station-card h3,
[data-theme="dark"] .challenge-card h3,
[data-theme="dark"] .run-status,
[data-theme="dark"] .metric-label {
  color: #c5d9eb;
}

[data-theme="dark"] .lab-tile {
  background: var(--rad-bg-panel);
  border-color: var(--rad-border);
}

[data-theme="dark"] .lab-tile h3 {
  color: #e2eaf2;
}

[data-theme="dark"] .stat-card {
  background: var(--rad-bg-panel);
  border-color: var(--rad-border);
}

[data-theme="dark"] .lab-nav {
  background: #0d1520;
  border-color: var(--rad-border);
}

[data-theme="dark"] .lab-nav-item {
  color: var(--rad-text-soft);
}

[data-theme="dark"] .lab-nav-item.active {
  color: #5eead4;
  border-bottom-color: #5eead4;
}

[data-theme="dark"] .data-table th {
  background: #162436;
  color: #e2eaf2;
  border-color: var(--rad-border);
}

[data-theme="dark"] .data-table td {
  border-color: var(--rad-border);
  color: var(--rad-text);
}

[data-theme="dark"] .data-table tr:nth-child(even) td {
  background: rgba(255, 255, 255, 0.02);
}

[data-theme="dark"] input[type=text],
[data-theme="dark"] textarea,
[data-theme="dark"] select {
  background: #0c141f;
  color: #e2eaf2;
  border-color: var(--rad-border);
}

[data-theme="dark"] .formula-box {
  background: #0d2730;
  border-left-color: var(--rad-teal);
  color: #b9eff0;
}

[data-theme="dark"] .assessment-note {
  background: #231d10;
  border-left-color: var(--rad-amber);
  color: #f7e6c4;
}

[data-theme="dark"] .assessment-note h3 {
  color: #fbd38d !important;
}

[data-theme="dark"] .lab-actionbar {
  background: #0d1520;
  border-color: var(--rad-border);
}

[data-theme="dark"] .handout-page {
  background: #111822;
  color: #e2eaf2;
}

[data-theme="dark"] .handout-header h1 {
  color: #e2eaf2;
}

[data-theme="dark"] .handout-section h2 {
  color: #e2eaf2;
}

/* ------------------------------------------------------------------------- */
/* Interactive Math Scratchpad ("Check My Formula")                          */
/* ------------------------------------------------------------------------- */
.math-scratchpad {
  margin: 18px 0;
  border: 1px solid var(--rad-border);
  border-radius: var(--rad-radius-sm);
  background: var(--rad-bg-soft);
  overflow: hidden;
}
.math-scratchpad-header {
  padding: 10px 14px;
  background: rgba(14, 124, 134, 0.08);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-weight: 700;
  font-size: 13px;
  color: var(--rad-teal);
  user-select: none;
}
.math-scratchpad-body {
  padding: 14px;
  display: grid;
  gap: 12px;
  border-top: 1px solid var(--rad-border);
}
.math-input-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 10px;
}
.math-input-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.math-input-card label {
  font-size: 11px;
  font-weight: 700;
  color: var(--rad-text-soft);
}
.math-input-card input {
  padding: 6px 8px;
  font-size: 13px;
  border-radius: 6px;
}
.math-feedback {
  padding: 10px 12px;
  border-radius: 6px;
  font-size: 12.5px;
  line-height: 1.4;
}
.math-feedback.valid {
  background: #eafaf1;
  color: #12633f;
  border: 1px solid #a3e6be;
}
[data-theme="dark"] .math-feedback.valid {
  background: #0f2e1f;
  color: #86efac;
  border-color: #166534;
}
.math-feedback.hint {
  background: #fff9ed;
  color: #92400e;
  border: 1px solid #fde68a;
}
[data-theme="dark"] .math-feedback.hint {
  background: #291d07;
  color: #fde68a;
  border-color: #78350f;
}

/* ------------------------------------------------------------------------- */
/* Console Exposure Flash & Audio Controls                                   */
/* ------------------------------------------------------------------------- */
.exposure-flash {
  animation: expFlash .35s ease-out;
}
@keyframes expFlash {
  0% { filter: brightness(1.7) contrast(1.2); }
  100% { filter: brightness(1) contrast(1); }
}

.topbar-pill-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.28);
  color: #fff;
  padding: 5px 12px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: all .15s ease;
}
.topbar-pill-btn:hover {
  background: rgba(255, 255, 255, 0.22);
  border-color: #fff;
}

/* ------------------------------------------------------------------------- */
/* Instructor Gradebook Modal                                                */
/* ------------------------------------------------------------------------- */
.gradebook-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(5, 14, 24, 0.75);
  backdrop-filter: blur(4px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.gradebook-modal {
  background: var(--rad-bg-panel);
  border: 1px solid var(--rad-border);
  border-radius: var(--rad-radius);
  width: 100%;
  max-width: 960px;
  max-height: 88vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--rad-shadow-lg);
  overflow: hidden;
}
.gradebook-modal-header {
  padding: 16px 22px;
  background: var(--rad-navy);
  color: #fff;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.gradebook-modal-body {
  padding: 22px;
  overflow-y: auto;
  flex-grow: 1;
}
.gradebook-dropzone {
  border: 2px dashed var(--rad-teal);
  border-radius: var(--rad-radius-sm);
  padding: 30px 20px;
  text-align: center;
  background: var(--rad-bg-soft);
  cursor: pointer;
  transition: background .2s ease;
}
.gradebook-dropzone:hover {
  background: rgba(14, 124, 134, 0.12);
}

/* ------------------------------------------------------------------------- */
/* Live Telemetry & Metric Card Status Indicators                            */
/* ------------------------------------------------------------------------- */
.metric {
  background: #fff;
  border: 1px solid var(--rad-border);
  border-radius: 10px;
  padding: 11px 13px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all .2s ease;
  position: relative;
}
.metric:hover {
  box-shadow: 0 4px 12px rgba(6, 26, 43, 0.08);
}
.metric.status-optimal {
  border-left: 4px solid var(--rad-teal);
  background: linear-gradient(180deg, #ffffff 0%, rgba(20, 184, 166, 0.04) 100%);
}
.metric.status-acceptable {
  border-left: 4px solid #3b82f6;
  background: linear-gradient(180deg, #ffffff 0%, rgba(59, 130, 246, 0.04) 100%);
}
.metric.status-warning {
  border-left: 4px solid var(--rad-amber);
  background: linear-gradient(180deg, #ffffff 0%, rgba(245, 158, 11, 0.05) 100%);
}
.metric.status-critical {
  border-left: 4px solid #ef4444;
  background: linear-gradient(180deg, #ffffff 0%, rgba(239, 68, 68, 0.06) 100%);
}
[data-theme="dark"] .metric {
  background: #0d1826;
  border-color: var(--rad-border);
}
[data-theme="dark"] .metric.status-optimal {
  background: linear-gradient(180deg, #0d1826 0%, rgba(20, 184, 166, 0.12) 100%);
}
[data-theme="dark"] .metric.status-acceptable {
  background: linear-gradient(180deg, #0d1826 0%, rgba(59, 130, 246, 0.12) 100%);
}
[data-theme="dark"] .metric.status-warning {
  background: linear-gradient(180deg, #0d1826 0%, rgba(245, 158, 11, 0.14) 100%);
}
[data-theme="dark"] .metric.status-critical {
  background: linear-gradient(180deg, #0d1826 0%, rgba(239, 68, 68, 0.15) 100%);
}
.metric-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 6px;
  margin-bottom: 4px;
}
.metric-label {
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .35px;
  color: var(--rad-text-faint);
}
.metric-badge {
  font-size: 9.5px;
  font-weight: 800;
  padding: 1px 6px;
  border-radius: 4px;
  letter-spacing: .4px;
  text-transform: uppercase;
}
.badge-optimal {
  background: rgba(20, 184, 166, 0.15);
  color: #0f766e;
}
[data-theme="dark"] .badge-optimal {
  background: rgba(20, 184, 166, 0.25);
  color: #5eead4;
}
.badge-acceptable {
  background: rgba(59, 130, 246, 0.15);
  color: #1d4ed8;
}
[data-theme="dark"] .badge-acceptable {
  background: rgba(59, 130, 246, 0.25);
  color: #93c5fd;
}
.badge-warning {
  background: rgba(245, 158, 11, 0.18);
  color: #b45309;
}
[data-theme="dark"] .badge-warning {
  background: rgba(245, 158, 11, 0.28);
  color: #fcd34d;
}
.badge-critical {
  background: rgba(239, 68, 68, 0.18);
  color: #b91c1c;
}
[data-theme="dark"] .badge-critical {
  background: rgba(239, 68, 68, 0.28);
  color: #fca5a5;
}
.metric strong {
  display: block;
  color: var(--rad-teal);
  font-size: 18px;
  font-weight: 700;
  line-height: 1.25;
  margin: 3px 0;
  font-family: var(--font-mono);
}
.metric small {
  display: block;
  color: var(--rad-text-soft);
  font-size: 11.5px;
  line-height: 1.35;
}

/* ---------------------------------------------------------------------- */
/* VPS Cloud Sync & Mode Badges                                           */
/* ---------------------------------------------------------------------- */
.sync-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.3px;
  text-transform: uppercase;
}
.sync-pill.online {
  background: rgba(16, 185, 129, 0.2);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.4);
}
.sync-pill.offline {
  background: rgba(148, 163, 184, 0.2);
  color: #cbd5e1;
  border: 1px solid rgba(148, 163, 184, 0.3);
}

.teacher-mode-banner {
  background: linear-gradient(90deg, #1e3a8a, #0284c7);
  color: #ffffff;
  padding: 8px 16px;
  font-size: 13px;
  font-weight: 700;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
}
.teacher-mode-banner button {
  background: #ffffff;
  color: #1e3a8a;
  border: none;
  border-radius: 6px;
  padding: 4px 12px;
  font-size: 12px;
  font-weight: 800;
  cursor: pointer;
}

/* ---------------------------------------------------------------------- */
/* Attachment Uploader & Lists                                            */
/* ---------------------------------------------------------------------- */
.attachment-dropzone {
  border: 2px dashed var(--rad-border);
  border-radius: var(--rad-radius-sm);
  padding: 24px;
  text-align: center;
  background: var(--rad-bg-soft);
  transition: all .2s ease;
  cursor: pointer;
  margin: 16px 0 12px;
}
.attachment-dropzone:hover, .attachment-dropzone.dragover {
  border-color: var(--rad-teal);
  background: rgba(14, 124, 134, 0.05);
}
.attachment-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}
.attachment-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #ffffff;
  border: 1px solid var(--rad-border);
  border-radius: 8px;
  padding: 8px 14px;
  font-size: 13px;
}
[data-theme="dark"] .attachment-item {
  background: #0e1726;
}
.attachment-item .file-info {
  display: flex;
  align-items: center;
  gap: 10px;
}
.attachment-item .file-name {
  font-weight: 700;
  color: var(--rad-blue-light);
}
.attachment-item .file-size {
  color: var(--rad-text-faint);
  font-size: 11.5px;
}

/* ---------------------------------------------------------------------- */
/* Graded Submission Feedback Card                                        */
/* ---------------------------------------------------------------------- */
.graded-feedback-card {
  background: linear-gradient(135deg, #0b2545 0%, #13315c 100%);
  color: #ffffff;
  border-radius: var(--rad-radius);
  padding: 24px;
  margin-bottom: 24px;
  box-shadow: var(--rad-shadow-lg);
  border: 1px solid #1e4976;
}
.graded-feedback-card .score-badge {
  font-size: 32px;
  font-weight: 800;
  color: #38bdf8;
  font-family: var(--font-mono);
}
.graded-feedback-card .rubric-pill-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
  margin: 16px 0;
}
@media (max-width: 768px) {
  .graded-feedback-card .rubric-pill-grid { grid-template-columns: repeat(2, 1fr); }
}
.rubric-pill {
  background: rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  padding: 10px;
  text-align: center;
  border: 1px solid rgba(255, 255, 255, 0.12);
}
.rubric-pill .pill-label { font-size: 11px; opacity: 0.8; text-transform: uppercase; }
.rubric-pill .pill-val { font-size: 18px; font-weight: 800; color: #7fe0d6; font-family: var(--font-mono); }

/* ---------------------------------------------------------------------- */
/* Teacher Drawer                                                         */
/* ---------------------------------------------------------------------- */
.teacher-drawer-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  z-index: 999;
  display: flex;
  justify-content: flex-end;
}
.teacher-drawer {
  width: 500px;
  max-width: 90vw;
  height: 100%;
  background: #ffffff;
  box-shadow: -4px 0 20px rgba(0,0,0,0.25);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  padding: 24px;
  color: var(--rad-text);
}
[data-theme="dark"] .teacher-drawer {
  background: #0e1726;
  color: #f1f5f9;
}
.teacher-drawer h2 {
  color: var(--rad-navy);
  margin-top: 0;
  border-bottom: 2px solid var(--rad-teal);
  padding-bottom: 8px;
}
.teacher-drawer .key-section {
  background: var(--rad-bg-soft);
  border-left: 4px solid var(--rad-teal);
  padding: 12px 16px;
  border-radius: 8px;
  margin: 12px 0;
  font-size: 13.5px;
}
[data-theme="dark"] .teacher-drawer .key-section {
  background: #1e293b;
}

.btn-delete-chip {
  background: #fee2e2;
  color: #991b1b;
  border: 1px solid #fca5a5;
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: all .15s ease;
  white-space: nowrap;
}
.btn-delete-chip:hover {
  background: #ef4444;
  color: #ffffff;
  border-color: #dc2626;
  box-shadow: 0 2px 6px rgba(239, 68, 68, 0.3);
}

.btn-clear-bar {
  background: #fee2e2;
  color: #991b1b;
  border: 1px solid #f87171;
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all .15s ease;
}
.btn-clear-bar:hover {
  background: #dc2626;
  color: #ffffff;
}