/* ═══════════════════════════════════════════════════
   Nido Hack '26 Admin — Styling
   Dark-mode-friendly, clean, functional
   ═══════════════════════════════════════════════════ */

:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-2: #21262d;
  --border: #30363d;
  --green: #3fb950;
  --green-dim: rgba(63, 185, 80, 0.15);
  --blue: #58a6ff;
  --red: #f85149;
  --red-dim: rgba(248, 81, 73, 0.15);
  --yellow: #e3b341;
  --text: #c9d1d9;
  --muted: #8b949e;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  line-height: 1.5;
  min-height: 100vh;
}

code {
  font-family: 'SF Mono', Monaco, 'Cascadia Code', monospace;
  background: var(--surface-2);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.9em;
}

/* ───────── HEADER ───────── */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

header h1 {
  color: var(--green);
  font-size: 1.5rem;
  text-shadow: 0 0 20px rgba(63, 185, 80, 0.3);
}

.subtitle {
  color: var(--muted);
  font-size: 0.85rem;
  margin-top: 2px;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.signed-in {
  color: var(--muted);
  font-size: 0.85rem;
  background: var(--surface-2);
  padding: 6px 12px;
  border-radius: 999px;
}

/* ───────── MAIN LAYOUT ───────── */
main {
  max-width: 1100px;
  margin: 24px auto;
  padding: 0 24px;
}

/* ───────── TABS ───────── */
.tabs {
  display: flex;
  gap: 4px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 24px;
}

.tab {
  background: transparent;
  border: none;
  color: var(--muted);
  padding: 12px 20px;
  cursor: pointer;
  font-size: 1rem;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: color 0.15s, border-color 0.15s;
}

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

.tab.active {
  color: var(--green);
  border-bottom-color: var(--green);
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ───────── CARDS ───────── */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  margin-bottom: 20px;
}

.card h2 {
  color: var(--text);
  font-size: 1.1rem;
  margin-bottom: 4px;
}

.card h3 {
  color: var(--text);
  font-size: 1rem;
  margin-bottom: 8px;
}

.card > p.muted {
  margin-bottom: 16px;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 12px;
}

.card-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.badge {
  background: var(--green-dim);
  color: var(--green);
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: normal;
  margin-left: 8px;
}

.muted { color: var(--muted); font-size: 0.9rem; }

/* ───────── FORMS ───────── */
form label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 12px;
}

form .req {
  color: var(--red);
}

form input, form textarea, form select {
  display: block;
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  padding: 8px 12px;
  font-size: 0.95rem;
  font-family: inherit;
  margin-top: 4px;
}

form input:focus, form textarea:focus, form select:focus {
  outline: none;
  border-color: var(--green);
  box-shadow: 0 0 0 3px var(--green-dim);
}

.form-row {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 12px;
  margin-bottom: 0;
}

.form-row > label { margin-bottom: 12px; }

.form-actions {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
  margin-top: 16px;
}

/* ───────── BUTTONS ───────── */
.btn-primary, .btn-secondary, .btn-danger {
  border: none;
  padding: 10px 18px;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.08s;
  font-family: inherit;
}

.btn-primary {
  background: var(--green);
  color: #000;
}
.btn-primary:hover { opacity: 0.9; }
.btn-primary:active { transform: scale(0.98); }
.btn-primary:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-secondary {
  background: var(--surface-2);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { background: var(--border); }

.btn-danger {
  background: transparent;
  color: var(--red);
  border: 1px solid var(--red);
  padding: 6px 14px;
  font-size: 0.85rem;
}
.btn-danger:hover { background: var(--red-dim); }

/* ───────── TABLE ───────── */
#studentsTableWrap {
  overflow-x: auto;
}

#studentsTable {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

#studentsTable th {
  text-align: left;
  padding: 12px 10px;
  color: var(--muted);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--border);
}

#studentsTable td {
  padding: 12px 10px;
  border-bottom: 1px solid var(--border);
}

#studentsTable tr:last-child td { border-bottom: none; }

#studentsTable td.empty {
  text-align: center;
  color: var(--muted);
  padding: 30px;
}

.status-pending { color: var(--muted); }
.status-sent { color: var(--green); font-weight: 500; }
.status-failed { color: var(--red); font-weight: 500; }
.status-sending { color: var(--yellow); font-weight: 500; }

.btn-row-delete {
  background: transparent;
  border: none;
  color: var(--muted);
  cursor: pointer;
  padding: 4px 8px;
  font-size: 1rem;
}
.btn-row-delete:hover { color: var(--red); }

/* Per-row inline action buttons (Send/Resend welcome + api key) */
.btn-row-action {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.7rem;
  cursor: pointer;
  font-family: inherit;
  margin-left: 8px;
  vertical-align: middle;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  white-space: nowrap;
}
.btn-row-action:hover {
  color: var(--green);
  border-color: var(--green);
  background: var(--green-dim);
}
.btn-row-action:active { transform: scale(0.96); }

/* ───────── API KEYS GRID ───────── */
.api-keys-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
  margin-bottom: 24px;
}

.api-key-field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.api-key-field label {
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 500;
}

.api-key-field input {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 8px 10px;
  color: var(--text);
  font-family: 'SF Mono', Monaco, monospace;
  font-size: 0.85rem;
}

.api-key-field input:focus {
  outline: none;
  border-color: var(--green);
}

/* ───────── RESULTS TOAST ───────── */
.results {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  flex-direction: column-reverse;
  gap: 8px;
  z-index: 100;
  max-width: 400px;
}

.toast {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left-width: 4px;
  padding: 12px 16px;
  border-radius: 6px;
  font-size: 0.9rem;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
  animation: slideIn 0.2s ease-out;
}

.toast.success { border-left-color: var(--green); }
.toast.error { border-left-color: var(--red); }
.toast.info { border-left-color: var(--blue); }

@keyframes slideIn {
  from { transform: translateX(20px); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* ───────── RESPONSIVE ───────── */
@media (max-width: 620px) {
  .header-inner { flex-direction: column; align-items: flex-start; }
  .form-row { grid-template-columns: 1fr; }
  .api-keys-grid { grid-template-columns: 1fr; }
  main { padding: 0 16px; }
  .card { padding: 16px; }
}