:root {
  --bg: #0a0c10;
  --card-bg: #151a22;
  --card-border: #262e3a;
  --text: #e8ecf1;
  --muted: #8a94a6;
  --green: #22c55e;
  --green-dim: #14532d;
  --grey: #6b7280;
  --grey-dim: #2a2f38;
  --amber: #f59e0b;
  --amber-dim: #4a3407;
}

* { box-sizing: border-box; }

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

body {
  display: flex;
  flex-direction: column;
}

main#cards {
  flex: 1 1 auto;
}

header {
  padding: 24px 32px;
  border-bottom: 1px solid var(--card-border);
  transition: background 0.4s ease;
}

header.stale {
  background: var(--amber-dim);
}

.header-main {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

h1 {
  margin: 0;
  font-size: 1.4rem;
  letter-spacing: 0.02em;
  color: var(--muted);
  text-transform: uppercase;
  font-weight: 600;
}

.header-status {
  font-size: 1.6rem;
  font-weight: 600;
  display: flex;
  gap: 12px;
  align-items: baseline;
}

.header-sub {
  margin-top: 8px;
  font-size: 1.1rem;
  color: var(--muted);
  display: flex;
  gap: 20px;
  align-items: center;
}

.muted { color: var(--muted); font-weight: 400; }

.stale-warning {
  color: var(--amber);
  font-weight: 700;
}

.hidden { display: none !important; }

main#cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(420px, 1fr));
  gap: 24px;
  padding: 32px;
  max-width: 1400px;
  margin: 0 auto;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.course-code {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: 0.01em;
}

.pill {
  font-size: 1.1rem;
  font-weight: 800;
  padding: 8px 20px;
  border-radius: 999px;
  letter-spacing: 0.05em;
  white-space: nowrap;
}

.pill-open {
  background: var(--green);
  color: #06210f;
}

.pill-closed {
  background: var(--grey-dim);
  color: var(--muted);
}

.pill-error {
  background: var(--amber);
  color: #3a2600;
}

.pill-checking {
  background: var(--amber-dim);
  color: var(--amber);
}

.pill.pulsing {
  animation: pulse 1s infinite;
}

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.7); }
  50% { box-shadow: 0 0 0 14px rgba(34, 197, 94, 0); }
}

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0;
  border-top: 1px solid var(--card-border);
  flex-wrap: wrap;
}

.row:first-of-type { border-top: none; }

.row-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.row-seq {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.row-detail {
  font-size: 0.95rem;
  color: var(--muted);
}

.row-status {
  font-size: 0.95rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 999px;
}

.row-status.opened {
  background: var(--green-dim);
  color: var(--green);
}

.row-status.closed {
  background: var(--grey-dim);
  color: var(--muted);
}

.row-status.unknown {
  background: var(--amber-dim);
  color: var(--amber);
}

footer {
  position: sticky;
  bottom: 0;
  display: flex;
  gap: 16px;
  justify-content: center;
  padding: 20px;
  background: linear-gradient(to top, var(--bg) 60%, transparent);
  flex-wrap: wrap;
}

.btn {
  font-size: 1.1rem;
  font-weight: 700;
  padding: 16px 28px;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  color: var(--text);
  transition: transform 0.1s ease, opacity 0.2s ease;
}

.btn small {
  font-weight: 400;
  opacity: 0.75;
  font-size: 0.7rem;
}

.btn:active { transform: scale(0.97); }

.btn-arm {
  background: #2563eb;
}

.btn-arm.armed {
  background: var(--green-dim);
  color: var(--green);
}

.btn-test {
  background: var(--card-border);
}

.btn-manage {
  background: var(--card-border);
}

.btn-ack {
  background: var(--amber);
  color: #3a2600;
  animation: pulse-ack 1s infinite;
}

@keyframes pulse-ack {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

/* ---- Manage targets modal ---- */

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  z-index: 10;
}

.modal {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 28px;
  max-width: 640px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-head h2 {
  margin: 0;
  font-size: 1.3rem;
}

.modal h3 {
  margin: 0 0 12px 0;
  font-size: 1rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.icon-btn {
  background: transparent;
  border: none;
  color: var(--muted);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 4px 10px;
  border-radius: 8px;
}

.icon-btn:hover {
  background: var(--card-border);
  color: var(--text);
}

.manage-course {
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 14px 16px;
  margin-bottom: 12px;
}

.manage-course-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.manage-course-head strong {
  font-size: 1.05rem;
}

.manage-seq-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.seq-chip {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--grey-dim);
  color: var(--text);
  border-radius: 999px;
  padding: 6px 8px 6px 14px;
  font-size: 0.9rem;
}

.seq-chip button {
  background: transparent;
  border: none;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.9rem;
  line-height: 1;
  padding: 2px 6px;
  border-radius: 999px;
}

.seq-chip button:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text);
}

.text-btn {
  background: transparent;
  border: none;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.85rem;
  text-decoration: underline;
  padding: 0;
}

.text-btn:hover {
  color: var(--text);
}

.add-form {
  display: flex;
  gap: 10px;
}

.add-form input {
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--card-border);
  color: var(--text);
  padding: 12px 14px;
  border-radius: 10px;
  font-size: 1rem;
}

.btn-find {
  background: #2563eb;
  padding: 12px 20px;
  font-size: 1rem;
}

.btn-add {
  background: var(--green);
  color: #06210f;
  width: 100%;
}

.section-choice {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 0;
  border-top: 1px solid var(--card-border);
}

.section-choice:first-child { border-top: none; }

.section-choice input[type="checkbox"] {
  margin-top: 4px;
  width: 18px;
  height: 18px;
}

.section-choice label {
  display: flex;
  flex-direction: column;
  gap: 2px;
  cursor: pointer;
}

.section-choice .sc-title {
  font-weight: 700;
}

.section-choice .sc-detail {
  font-size: 0.85rem;
  color: var(--muted);
}

.section-choice.already label {
  color: var(--muted);
  cursor: default;
}

@media (max-width: 600px) {
  main#cards { grid-template-columns: 1fr; padding: 16px; }
  header { padding: 16px; }
  .modal { padding: 20px; }
  .add-form { flex-direction: column; }
}