:root {
  color-scheme: light;
  --bg: #ffffff;
  --surface: #f1f5f9;
  --text: #1e293b;
  --muted: #64748b;
  /* Same brand palette as the sibling apps at chandrashaker.in: blue for
     everyday navigation, orange reserved for the final commit action. */
  --accent: #1565c0;
  --accent-text: #ffffff;
  --highlight: #ff8f00;
  --highlight-text: #1c1300;
  --danger: #dc2626;
  --warning: #b45309;
  --border: #d1d5db;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

#app {
  max-width: 480px;
  margin: 0 auto;
  padding: 24px 20px 48px;
}

.hidden { display: none !important; }

h1 {
  display: inline-block;
  font-size: 1.4rem;
  margin: 0 0 8px;
  padding-bottom: 6px;
  border-bottom: 3px solid var(--highlight);
}

h2 {
  font-size: 1rem;
  color: var(--text);
  margin: 20px 0 8px;
}

.hint {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0 0 20px;
}

label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin: 16px 0 6px;
}

input[type="text"], input[type="number"], select {
  width: 100%;
  padding: 12px 14px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font-size: 1rem;
}

input[type="text"]:focus, input[type="number"]:focus, select:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

input.invalid {
  border-color: var(--danger);
  outline-color: var(--danger);
}

.field-error {
  color: var(--danger);
  font-size: 0.75rem;
  margin-top: 2px;
}

.button-stack {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 24px;
}

.button-row {
  display: flex;
  gap: 12px;
  margin-top: 24px;
}

.button-row button { flex: 1; }

button {
  padding: 14px 16px;
  border-radius: 10px;
  border: none;
  background: var(--accent);
  color: var(--accent-text);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

button.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

#marksSubmitBtn, #createExamSubmitBtn {
  background: var(--highlight);
  color: var(--highlight-text);
}

/* ---- Mode toggle (Home screen) ---- */
.mode-toggle {
  display: flex;
  gap: 8px;
  margin-top: 12px;
  background: var(--surface);
  border-radius: 10px;
  padding: 4px;
}

.mode-btn {
  flex: 1;
  background: transparent;
  color: var(--muted);
  padding: 10px;
}

.mode-btn.active {
  background: var(--accent);
  color: var(--accent-text);
}

/* ---- Preview area (capture review + marks-screen reference photo) ---- */
.preview-area {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  min-height: 200px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background: var(--surface);
}

.preview-area img {
  max-width: 100%;
  max-height: 65vh;
  border-radius: 6px;
}

.preview-area .view-full-size {
  color: var(--accent);
  font-size: 0.85rem;
  text-decoration: none;
}

.preview-area .view-full-size:hover {
  text-decoration: underline;
}

.spinner {
  width: 40px;
  height: 40px;
  margin: 24px auto;
  border: 4px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

#screen-processing, #screen-done {
  text-align: center;
}

.error {
  color: var(--danger);
  font-size: 0.9rem;
  margin-top: 12px;
}

/* ---- Marks entry grid ---- */
.marks-layout {
  margin-top: 16px;
}

.marks-preview {
  margin-bottom: 20px;
  max-height: 45vh;
}

.marks-preview img {
  max-height: 42vh;
}

.q1-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
}

.mark-field {
  display: flex;
  flex-direction: column;
}

.mark-field label {
  margin: 0 0 4px;
  font-size: 0.75rem;
  text-transform: uppercase;
  text-align: center;
}

.mark-field input {
  padding: 8px 6px;
  text-align: center;
}

.q-groups {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.q-group {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px;
  background: var(--surface);
}

.q-group-title {
  font-size: 0.8rem;
  color: var(--muted);
  margin: 0 0 8px;
  display: flex;
  justify-content: space-between;
}

.q-group-fields {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.totals-summary {
  margin-top: 24px;
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
}

.totals-summary > div {
  display: flex;
  justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  font-size: 0.9rem;
}

.totals-summary > div:last-child { border-bottom: none; }

.totals-summary .totals-final {
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 700;
}

.confirm-checkbox {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin: 20px 0 0;
  font-size: 0.85rem;
  color: var(--text);
  cursor: pointer;
}

.confirm-checkbox input {
  margin-top: 3px;
  width: auto;
}

/* ---- Faculty submissions list ---- */
.submissions-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 16px;
}

.submission-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  cursor: pointer;
  text-align: left;
  font-size: 0.9rem;
  color: var(--text);
}

.submission-row:hover {
  border-color: var(--accent);
}

.submission-row .roll {
  font-weight: 600;
}

.submission-row .meta {
  color: var(--muted);
  font-size: 0.8rem;
}

#submitAnotherBtn { margin-top: 12px; width: 100%; }

.done-nav {
  display: flex;
  gap: 12px;
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

.done-nav a {
  flex: 1;
  text-align: center;
  padding: 12px 16px;
  border-radius: 10px;
  border: none;
  background: var(--accent);
  color: var(--accent-text);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
}

.done-nav a:hover {
  opacity: 0.9;
}

@media (min-width: 700px) {
  #app { max-width: 1000px; }

  .marks-layout {
    display: flex;
    align-items: flex-start;
    gap: 24px;
  }

  .marks-preview {
    flex: 0 0 42%;
    margin-bottom: 0;
    max-height: none;
    position: sticky;
    top: 16px;
  }

  .marks-preview img {
    max-height: 85vh;
  }

  .marks-fields {
    flex: 1;
    min-width: 0;
  }
}