:root {
  --bg: #0a0e17;
  --bg-card: #111827;
  --bg-card-hover: #1a2234;
  --bg-input: #0d1321;
  --border: #1e293b;
  --border-glow: #00ff8830;
  --text: #e2e8f0;
  --text-dim: #64748b;
  --text-bright: #f8fafc;
  --accent: #00ff88;
  --accent-dim: #00cc6a;
  --danger: #ff4757;
  --warning: #ffa502;
  --info: #3b82f6;
  --gold: #ffd700;
  --silver: #c0c0c0;
  --bronze: #cd7f32;
  --radius: 8px;
  --radius-lg: 12px;
  --font-mono: 'JetBrains Mono', monospace;
  --font-sans: 'Inter', system-ui, sans-serif;
}

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

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
}

.hidden { display: none !important; }

/* NAV */
nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  height: 60px;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: .5rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.1rem;
}

.brand-icon { color: var(--accent); font-size: 1.4rem; }
.brand-text { color: var(--text-bright); }

.nav-links { display: flex; gap: .25rem; }

.nav-link {
  color: var(--text-dim);
  text-decoration: none;
  padding: .5rem 1rem;
  border-radius: var(--radius);
  font-size: .9rem;
  font-weight: 500;
  transition: all .2s;
}

.nav-link:hover, .nav-link.active {
  color: var(--accent);
  background: rgba(0, 255, 136, .08);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-user {
  font-family: var(--font-mono);
  font-size: .85rem;
  color: var(--text);
}

.nav-score {
  font-family: var(--font-mono);
  font-size: .85rem;
  color: var(--accent);
  font-weight: 700;
}

/* BUTTONS */
.btn {
  font-family: var(--font-sans);
  font-weight: 600;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all .2s;
  font-size: .9rem;
  padding: .6rem 1.2rem;
}

.btn-primary {
  background: var(--accent);
  color: var(--bg);
}

.btn-primary:hover { background: var(--accent-dim); transform: translateY(-1px); }

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

.btn-outline:hover { border-color: var(--accent); color: var(--accent); }

.btn-sm { padding: .35rem .8rem; font-size: .8rem; }
.btn-full { width: 100%; padding: .75rem; }

.btn-challenge {
  background: rgba(0, 255, 136, .1);
  color: var(--accent);
  border: 1px solid rgba(0, 255, 136, .2);
  font-size: .8rem;
  padding: .4rem 1rem;
}

.btn-challenge:hover {
  background: rgba(0, 255, 136, .2);
  border-color: var(--accent);
}

.btn-solved {
  background: rgba(0, 255, 136, .15);
  color: var(--accent);
  border: 1px solid var(--accent);
  cursor: default;
}

/* AUTH */
.auth-container {
  max-width: 420px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.auth-header {
  text-align: center;
  margin-bottom: 2rem;
}

.skull-big { font-size: 3rem; display: block; margin-bottom: .5rem; color: var(--accent); }

.auth-header h1 {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--text-bright);
}

.glow {
  color: var(--accent);
  text-shadow: 0 0 20px rgba(0, 255, 136, .5);
}

.subtitle {
  color: var(--text-dim);
  font-size: .9rem;
  margin-top: .25rem;
}

.auth-tabs {
  display: flex;
  gap: .25rem;
  margin-bottom: 1.5rem;
  background: var(--bg-input);
  border-radius: var(--radius);
  padding: 4px;
}

.auth-tab {
  flex: 1;
  padding: .6rem;
  border: none;
  background: transparent;
  color: var(--text-dim);
  font-weight: 600;
  font-size: .9rem;
  border-radius: 6px;
  cursor: pointer;
  transition: all .2s;
  font-family: var(--font-sans);
}

.auth-tab.active {
  background: var(--bg-card);
  color: var(--accent);
}

.form-group { margin-bottom: 1rem; }

.form-group label {
  display: block;
  font-size: .8rem;
  font-weight: 600;
  color: var(--text-dim);
  margin-bottom: .35rem;
  text-transform: uppercase;
  letter-spacing: .5px;
}

.form-group input {
  width: 100%;
  padding: .7rem .9rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-bright);
  font-size: .95rem;
  font-family: var(--font-mono);
  transition: border-color .2s;
}

.form-group input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(0, 255, 136, .1);
}

.form-error, .form-result {
  margin-top: .75rem;
  padding: .6rem .9rem;
  border-radius: var(--radius);
  font-size: .85rem;
  font-weight: 500;
}

.form-error:empty, .form-result:empty { display: none; }

.form-error {
  background: rgba(255, 71, 87, .1);
  border: 1px solid rgba(255, 71, 87, .3);
  color: var(--danger);
}

.form-result.success {
  background: rgba(0, 255, 136, .1);
  border: 1px solid rgba(0, 255, 136, .3);
  color: var(--accent);
}

.form-result.error {
  background: rgba(255, 71, 87, .1);
  border: 1px solid rgba(255, 71, 87, .3);
  color: var(--danger);
}

.form-result.info {
  background: rgba(255, 165, 2, .1);
  border: 1px solid rgba(255, 165, 2, .3);
  color: var(--warning);
}

.auth-footer {
  margin-top: 2rem;
  text-align: center;
  color: var(--text-dim);
  font-size: .8rem;
}

/* CONTAINER */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.page-header {
  margin-bottom: 2rem;
}

.page-header h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text-bright);
}

.page-header p {
  color: var(--text-dim);
  font-size: .9rem;
  margin-top: .25rem;
}

/* CHALLENGES */
.category-section {
  margin-bottom: 2.5rem;
}

.category-header {
  display: flex;
  align-items: center;
  gap: .75rem;
  margin-bottom: 1rem;
  padding-bottom: .75rem;
  border-bottom: 1px solid var(--border);
}

.category-code {
  font-family: var(--font-mono);
  font-size: .75rem;
  font-weight: 700;
  color: var(--bg);
  background: var(--accent);
  padding: .2rem .6rem;
  border-radius: 4px;
}

.category-name {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-bright);
}

.challenge-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1rem;
}

.challenge-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  transition: all .2s;
}

.challenge-card:hover {
  border-color: rgba(0, 255, 136, .3);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 24px rgba(0, 0, 0, .3);
}

.challenge-card.solved {
  border-color: rgba(0, 255, 136, .4);
  background: rgba(0, 255, 136, .03);
}

.card-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: .75rem;
}

.card-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-bright);
}

.card-points {
  font-family: var(--font-mono);
  font-size: .85rem;
  font-weight: 700;
  color: var(--accent);
  white-space: nowrap;
}

.card-desc {
  font-size: .85rem;
  color: var(--text-dim);
  margin-bottom: 1rem;
  line-height: 1.5;
}

.card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.card-stats {
  display: flex;
  gap: 1rem;
  font-size: .75rem;
  color: var(--text-dim);
  font-family: var(--font-mono);
}

.stat-claims {
  color: var(--warning);
}

.stat-claims.exhausted {
  color: var(--danger);
}

/* SCOREBOARD */
.scoreboard-table {
  width: 100%;
  border-collapse: collapse;
}

.scoreboard-table th {
  text-align: left;
  padding: .75rem 1rem;
  font-size: .75rem;
  font-weight: 700;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: .5px;
  border-bottom: 1px solid var(--border);
}

.scoreboard-table td {
  padding: .75rem 1rem;
  border-bottom: 1px solid var(--border);
  font-size: .9rem;
}

.scoreboard-table tr:hover td {
  background: var(--bg-card-hover);
}

.rank-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: .8rem;
}

.rank-1 { background: var(--gold); color: #000; }
.rank-2 { background: var(--silver); color: #000; }
.rank-3 { background: var(--bronze); color: #000; }
.rank-other { background: var(--bg-card); color: var(--text-dim); border: 1px solid var(--border); }

.score-value {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--accent);
}

.solves-value {
  font-family: var(--font-mono);
  color: var(--text-dim);
}

.current-user td { background: rgba(0, 255, 136, .05) !important; }

/* PROFILE */
.profile-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  max-width: 600px;
}

.profile-stat {
  display: flex;
  justify-content: space-between;
  padding: .75rem 0;
  border-bottom: 1px solid var(--border);
}

.profile-stat:last-child { border-bottom: none; }

.profile-stat-label {
  color: var(--text-dim);
  font-size: .85rem;
  font-weight: 600;
  text-transform: uppercase;
}

.profile-stat-value {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--text-bright);
}

.profile-solves {
  margin-top: 1.5rem;
}

.profile-solves h3 {
  font-size: 1rem;
  margin-bottom: 1rem;
  color: var(--text-bright);
}

.solve-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: .5rem 0;
  border-bottom: 1px solid var(--border);
  font-size: .85rem;
}

.solve-item .solve-name { color: var(--text); }
.solve-item .solve-points { font-family: var(--font-mono); color: var(--accent); }
.solve-item .solve-no-points { font-family: var(--font-mono); color: var(--text-dim); }

/* MODAL */
.modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, .7);
  backdrop-filter: blur(4px);
}

.modal-content {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  width: 90%;
  max-width: 440px;
  animation: modalIn .2s ease;
}

@keyframes modalIn {
  from { opacity: 0; transform: scale(.95) translateY(10px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-content h3 {
  font-size: 1.2rem;
  color: var(--text-bright);
  margin-bottom: .25rem;
}

.modal-content p {
  color: var(--text-dim);
  font-size: .85rem;
  margin-bottom: 1.25rem;
}

.modal-actions {
  display: flex;
  gap: .75rem;
  margin-top: 1rem;
}

/* URL LINK */
.challenge-url {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .75rem;
  color: var(--info);
  text-decoration: none;
  margin-bottom: .75rem;
  opacity: .8;
}

.challenge-url:hover { opacity: 1; text-decoration: underline; }

/* CHALLENGE STATES */
.challenge-card.waiting {
  opacity: .5;
  border-color: var(--border);
}

.challenge-card.waiting:hover {
  transform: none;
  border-color: var(--border);
  background: var(--bg-card);
  box-shadow: none;
}

.challenge-card.theoretical {
  border-color: rgba(139, 92, 246, .3);
  background: rgba(139, 92, 246, .03);
}

.status-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .65rem;
  font-weight: 700;
  padding: .15rem .5rem;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: .5px;
}

.status-waiting {
  background: rgba(100, 116, 139, .2);
  color: var(--text-dim);
  border: 1px solid rgba(100, 116, 139, .3);
}

.status-active {
  background: rgba(0, 255, 136, .15);
  color: var(--accent);
  border: 1px solid rgba(0, 255, 136, .3);
}

.status-theoretical {
  background: rgba(139, 92, 246, .15);
  color: #a78bfa;
  border: 1px solid rgba(139, 92, 246, .3);
}

/* ADMIN */
.nav-admin { color: #ffa502 !important; }
.nav-admin:hover, .nav-admin.active { color: #ffa502 !important; background: rgba(255, 165, 2, .1) !important; }

.admin-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: .5rem;
}

.admin-card-info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.admin-card-title {
  font-weight: 600;
  color: var(--text-bright);
  font-size: .95rem;
}

.admin-card-cat {
  font-family: var(--font-mono);
  font-size: .75rem;
  color: var(--text-dim);
}

.admin-card-actions { display: flex; gap: .5rem; }

.btn-start {
  background: rgba(0, 255, 136, .15);
  color: var(--accent);
  border: 1px solid rgba(0, 255, 136, .3);
  font-size: .8rem;
  padding: .35rem .8rem;
}

.btn-start:hover { background: rgba(0, 255, 136, .25); }

.btn-stop {
  background: rgba(255, 71, 87, .15);
  color: var(--danger);
  border: 1px solid rgba(255, 71, 87, .3);
  font-size: .8rem;
  padding: .35rem .8rem;
}

.btn-stop:hover { background: rgba(255, 71, 87, .25); }

/* SCROLLBAR */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #334155; }

/* RESPONSIVE */
@media (max-width: 768px) {
  nav { padding: 0 1rem; flex-wrap: wrap; height: auto; padding: .75rem 1rem; gap: .5rem; }
  .nav-links { order: 3; width: 100%; justify-content: center; }
  .challenge-cards { grid-template-columns: 1fr; }
  .container { padding: 1.5rem 1rem; }
}