@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:ital,opsz,wght@0,8..60,400;0,8..60,600;1,8..60,500&family=IBM+Plex+Sans:wght@400;500;600&family=IBM+Plex+Mono:wght@400;500&display=swap');

:root {
  --sky: #EAF3FC;
  --ink: #F2F6FB;
  --paper: #FFFFFF;
  --paper-raised: #EEF3FA;
  --text: #1E2A3A;
  --text-dim: #64748B;
  --hairline: #DCE7F2;
  --teal: #0B8074;
  --teal-bright: #14B8A6;
  --teal-dim: #E1F7F5;
  --clay: #DC5B44;
  --clay-dim: #FFE7E1;
  --amber: #C4791C;
  --amber-dim: #FFF1DC;
  --violet: #6D5DD3;
  --violet-dim: #EDEAFC;
  --shadow: 0 1px 3px rgba(30,42,58,0.07), 0 1px 2px rgba(30,42,58,0.05);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background-color: var(--sky);
  background-image:
    radial-gradient(circle at 12% 8%, rgba(11,128,116,0.10), transparent 38%),
    radial-gradient(circle at 88% 0%, rgba(109,93,211,0.10), transparent 42%),
    radial-gradient(circle at 50% 100%, rgba(196,121,28,0.08), transparent 46%);
  background-attachment: fixed;
  color: var(--text);
  font-family: 'IBM Plex Sans', sans-serif;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

h1, h2, h3, .display {
  font-family: 'Source Serif 4', serif;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0;
}

.mono {
  font-family: 'IBM Plex Mono', monospace;
  letter-spacing: 0.02em;
}

/* ---- Auth page layout ---- */

.auth-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.auth-card {
  width: 100%;
  max-width: 380px;
  background: var(--paper);
  border: 1px solid var(--hairline);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

/* Signature element: animated ECG trace across the top of the card */
.trace {
  width: 100%;
  height: 44px;
  display: block;
  background: var(--paper-raised);
  border-bottom: 1px solid var(--hairline);
}

.trace path {
  fill: none;
  stroke: url(#traceGradient);
  stroke-width: 2;
  stroke-dasharray: 340;
  stroke-dashoffset: 340;
  animation: draw 2.6s ease-in-out infinite;
}

@keyframes draw {
  0%   { stroke-dashoffset: 340; }
  55%  { stroke-dashoffset: 0; }
  100% { stroke-dashoffset: -340; }
}

@media (prefers-reduced-motion: reduce) {
  .trace path { animation: none; stroke-dashoffset: 0; }
}

.auth-body {
  padding: 32px 28px 28px;
}

.eyebrow {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--teal);
  margin-bottom: 6px;
}

.auth-body h1 {
  font-size: 24px;
  margin-bottom: 4px;
}

.auth-sub {
  color: var(--text-dim);
  font-size: 14px;
  margin-bottom: 24px;
}

.field {
  margin-bottom: 16px;
}

.field label {
  display: block;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 6px;
}

.field input {
  width: 100%;
  background: var(--ink);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  padding: 11px 12px;
  color: var(--text);
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 15px;
}

.field input:focus {
  outline: 2px solid var(--teal-bright);
  outline-offset: 1px;
  border-color: var(--teal);
}

.btn {
  width: 100%;
  padding: 12px;
  border-radius: 6px;
  border: none;
  font-family: 'IBM Plex Sans', sans-serif;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
}

.btn-primary {
  background: var(--teal);
  color: #ffffff;
  margin-top: 4px;
}

.btn-primary:hover { background: var(--teal-bright); }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

.switch-mode {
  text-align: center;
  margin-top: 18px;
  font-size: 13px;
  color: var(--text-dim);
}

.switch-mode button {
  background: none;
  border: none;
  color: var(--teal);
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  text-decoration: underline;
  padding: 0;
}

.msg {
  font-size: 13px;
  padding: 10px 12px;
  border-radius: 6px;
  margin-bottom: 16px;
  display: none;
}

.msg.show { display: block; }
.msg.error { background: var(--clay-dim); color: var(--clay); border: 1px solid var(--clay); }
.msg.ok { background: var(--teal-dim); color: var(--teal); border: 1px solid var(--teal); }

/* ---- Site nav ---- */

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--hairline);
  background: var(--paper);
  box-shadow: var(--shadow);
  flex-wrap: wrap;
  gap: 12px;
  position: relative;
  z-index: 2;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-brand .display {
  font-size: 19px;
  background: linear-gradient(90deg, var(--teal), var(--violet));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav-brand .eyebrow {
  margin: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
}

.nav-links a.active {
  color: var(--teal);
}

.nav-links a:hover {
  color: var(--text);
}

.nav-user {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-user button {
  background: none;
  border: 1px solid var(--hairline);
  color: var(--text-dim);
  border-radius: 6px;
  padding: 6px 12px;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 13px;
  cursor: pointer;
}

.nav-user button:hover {
  border-color: var(--teal);
  color: var(--teal);
}

.btn-new {
  display: inline-block;
  background: var(--teal);
  color: #ffffff;
  padding: 8px 16px;
  border-radius: 6px;
  font-weight: 600;
  font-size: 13px;
  text-decoration: none;
}

.btn-new:hover { background: var(--teal-bright); }

/* ---- Page shell ---- */

.page {
  flex: 1;
  max-width: 760px;
  width: 100%;
  margin: 0 auto;
  padding: 32px 24px 64px;
}

.page-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 24px;
  flex-wrap: wrap;
  gap: 12px;
}

.page-header h1 {
  font-size: 26px;
}

/* ---- Date-wise topic feed ---- */

.date-group {
  margin-bottom: 28px;
}

.date-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--teal);
  padding-bottom: 8px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--hairline);
}

.topic-card {
  display: block;
  background: var(--paper);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  padding: 16px 18px;
  margin-bottom: 10px;
  text-decoration: none;
  color: var(--text);
  box-shadow: var(--shadow);
}

.topic-card:hover {
  border-color: var(--teal-bright);
}

.topic-top {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
  flex-wrap: wrap;
}

.tag {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10.5px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 20px;
  background: var(--violet-dim);
  color: var(--violet);
  border: 1px solid var(--violet-dim);
}

.topic-title {
  font-family: 'Source Serif 4', serif;
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 6px;
}

.topic-meta {
  font-size: 12.5px;
  color: var(--text-dim);
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.answer-count.has-verified { color: var(--teal); font-weight: 600; }

.empty-state {
  color: var(--text-dim);
  font-size: 14px;
  padding: 40px 0;
  text-align: center;
}

.loading {
  color: var(--text-dim);
  font-size: 13px;
  font-family: 'IBM Plex Mono', monospace;
  padding: 20px 0;
}

/* ---- System browse grid ---- */

.system-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
}

.system-card {
  display: block;
  background: var(--paper);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  padding: 18px;
  text-decoration: none;
  color: var(--text);
  box-shadow: var(--shadow);
}

.system-card:hover {
  border-color: var(--teal-bright);
}

.system-card .display {
  font-size: 17px;
  margin-bottom: 4px;
  background: none;
  -webkit-text-fill-color: var(--text);
}

.system-card .system-count {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  color: var(--text-dim);
}

.back-link {
  display: inline-block;
  color: var(--text-dim);
  text-decoration: none;
  font-size: 13px;
  margin-bottom: 16px;
}

.back-link:hover { color: var(--teal); }

/* ---- Forms (new topic / new answer) ---- */

.form-card {
  background: var(--paper);
  border: 1px solid var(--hairline);
  border-radius: 10px;
  padding: 24px;
  box-shadow: var(--shadow);
}

.field select,
.field textarea {
  width: 100%;
  background: var(--ink);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  padding: 11px 12px;
  color: var(--text);
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 15px;
}

.field select:focus,
.field textarea:focus {
  outline: 2px solid var(--teal-bright);
  outline-offset: 1px;
  border-color: var(--teal);
}

.field textarea {
  min-height: 140px;
  resize: vertical;
  font-family: 'IBM Plex Sans', sans-serif;
}

.btn-secondary {
  background: none;
  border: 1px solid var(--hairline);
  color: var(--text-dim);
}

.btn-secondary:hover {
  border-color: var(--teal);
  color: var(--teal);
}

.btn-row {
  display: flex;
  gap: 10px;
}

.btn-row .btn { width: auto; padding: 12px 20px; }

/* ---- Topic detail page ---- */

.topic-header {
  margin-bottom: 24px;
}

.topic-header .topic-title {
  font-size: 26px;
  margin-bottom: 10px;
}

.topic-body {
  font-size: 15px;
  line-height: 1.65;
  white-space: pre-wrap;
  color: var(--text);
  margin: 16px 0 8px;
}

.answers-heading {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--teal);
  margin: 32px 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--hairline);
}

.answer-card {
  background: var(--paper);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  padding: 16px 18px;
  margin-bottom: 12px;
  box-shadow: var(--shadow);
}

.answer-card.verdict-correct { border-color: var(--teal-bright); border-width: 1.5px; }
.answer-card.verdict-wrong { border-color: var(--clay); border-width: 1.5px; opacity: 0.9; }

.answer-body {
  font-size: 14.5px;
  line-height: 1.6;
  white-space: pre-wrap;
  margin-bottom: 10px;
}

.answer-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

.verdict-badge {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 3px 9px;
  border-radius: 20px;
}

.verdict-badge.correct { background: var(--teal-dim); color: var(--teal); }
.verdict-badge.wrong { background: var(--clay-dim); color: var(--clay); }
.verdict-badge.unverified { background: var(--paper-raised); color: var(--text-dim); }

.review-controls {
  display: flex;
  gap: 8px;
}

.review-controls button {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 12px;
  font-weight: 500;
  padding: 5px 11px;
  border-radius: 6px;
  cursor: pointer;
  border: 1px solid var(--hairline);
  background: none;
  color: var(--text-dim);
}

.review-controls button.mark-correct:hover { border-color: var(--teal); color: var(--teal); background: var(--teal-dim); }
.review-controls button.mark-wrong:hover { border-color: var(--clay); color: var(--clay); background: var(--clay-dim); }

/* ---- Admin panel ---- */

.admin-section {
  margin-bottom: 40px;
}

.admin-section h2 {
  font-size: 18px;
  margin-bottom: 14px;
}

.admin-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--paper);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.admin-table th {
  text-align: left;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-dim);
  padding: 10px 14px;
  border-bottom: 1px solid var(--hairline);
  background: var(--paper-raised);
}

.admin-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--hairline);
  font-size: 13.5px;
}

.admin-table tr:last-child td { border-bottom: none; }

.role-select {
  background: var(--ink);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  color: var(--text);
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 13px;
  padding: 5px 8px;
}

.admin-btn {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 12.5px;
  font-weight: 500;
  padding: 5px 12px;
  border-radius: 6px;
  cursor: pointer;
  border: 1px solid var(--hairline);
  background: none;
  color: var(--text-dim);
  margin-right: 6px;
}

.admin-btn:hover { border-color: var(--teal); color: var(--teal); background: var(--teal-dim); }
.admin-btn.danger:hover { border-color: var(--clay); color: var(--clay); background: var(--clay-dim); }

.badge-role {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10.5px;
  text-transform: uppercase;
  padding: 2px 7px;
  border-radius: 20px;
  background: var(--paper-raised);
  color: var(--text-dim);
}

.badge-role.admin { color: var(--amber); background: var(--amber-dim); }
.badge-role.reviewer { color: var(--violet); background: var(--violet-dim); }

.inline-form {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
}

.inline-form input {
  flex: 1;
  background: var(--ink);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  padding: 9px 12px;
  color: var(--text);
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 14px;
}