/* =========================================================
   BTC Puzzle Research Lab — Dark Theme UI
   ========================================================= */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500;700&display=swap');

/* ── CSS Variables ──────────────────────────────────────── */
:root {
  --bg-base:       #0d1117;
  --bg-card:       #161b22;
  --bg-card-hover: #1c2128;
  --bg-card2:      #21262d;
  --border:        #30363d;
  --border-light:  #21262d;
  --accent-green:  #00ff41;
  --accent-green2: #39d353;
  --accent-blue:   #58a6ff;
  --accent-orange: #f78166;
  --accent-yellow: #e3b341;
  --accent-purple: #bc8cff;
  --text-primary:  #c9d1d9;
  --text-secondary:#8b949e;
  --text-muted:    #484f58;
  --text-white:    #f0f6fc;

  --rank-s: #ff6b6b;
  --rank-a: #ff9f43;
  --rank-b: #ffd32a;
  --rank-c: #58a6ff;
  --rank-d: #8b949e;

  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --radius-sm: 4px;
  --radius:    8px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  --shadow-sm: 0 1px 3px rgba(0,0,0,.4);
  --shadow:    0 4px 16px rgba(0,0,0,.5);
  --shadow-lg: 0 8px 32px rgba(0,0,0,.6);
  --glow-green: 0 0 20px rgba(0,255,65,.15);
}

/* ── Reset & Base ───────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent-blue); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Scrollbar ──────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-base); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ── Utility ────────────────────────────────────────────── */
.mono { font-family: var(--font-mono); }
.text-green  { color: var(--accent-green2); }
.text-blue   { color: var(--accent-blue); }
.text-orange { color: var(--accent-orange); }
.text-yellow { color: var(--accent-yellow); }
.text-muted  { color: var(--text-secondary); }
.text-sm     { font-size: .875rem; }
.text-xs     { font-size: .75rem; }

/* ── Navigation ─────────────────────────────────────────── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13,17,23,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 1.5rem;
}

.nav-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: .6rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1rem;
  color: var(--accent-green);
  letter-spacing: -.02em;
  text-shadow: var(--glow-green);
}

.nav-logo .logo-icon {
  width: 28px; height: 28px;
  background: linear-gradient(135deg, var(--accent-green) 0%, #00cc33 100%);
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: .9rem;
  color: var(--bg-base);
  box-shadow: var(--glow-green);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
}

.nav-links a {
  font-size: .875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color .2s;
}
.nav-links a:hover,
.nav-links a.active { color: var(--text-white); text-decoration: none; }
.nav-links a.active { color: var(--accent-green); }

/* ── Hero ───────────────────────────────────────────────── */
.hero {
  padding: 5rem 1.5rem 4rem;
  text-align: center;
  background: radial-gradient(ellipse 60% 40% at 50% 0%, rgba(0,255,65,.06) 0%, transparent 70%);
  border-bottom: 1px solid var(--border-light);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  background: rgba(0,255,65,.08);
  border: 1px solid rgba(0,255,65,.2);
  border-radius: 999px;
  padding: .3rem .85rem;
  font-size: .75rem;
  font-family: var(--font-mono);
  color: var(--accent-green2);
  letter-spacing: .05em;
  margin-bottom: 1.5rem;
}

.hero-badge::before {
  content: '';
  display: inline-block;
  width: 6px; height: 6px;
  background: var(--accent-green2);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  color: var(--text-white);
  letter-spacing: -.03em;
  line-height: 1.15;
  margin-bottom: 1rem;
}

.hero h1 span { color: var(--accent-green); }

.hero-sub {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2.5rem;
}

/* Stats Bar */
.stats-bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem 2rem;
  margin-bottom: 2.5rem;
}

.stat-item {
  text-align: center;
}

.stat-value {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-white);
  line-height: 1;
}

.stat-value.green { color: var(--accent-green2); }
.stat-value.blue  { color: var(--accent-blue); }
.stat-value.orange { color: var(--accent-orange); }

.stat-label {
  font-size: .7rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-top: .25rem;
}

/* CTA Button */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  border: none;
  border-radius: var(--radius);
  font-family: var(--font-body);
  font-weight: 600;
  cursor: pointer;
  transition: all .2s;
  text-decoration: none;
}

.btn-primary {
  background: var(--accent-green);
  color: var(--bg-base);
  padding: .7rem 1.6rem;
  font-size: .95rem;
  box-shadow: var(--glow-green);
}
.btn-primary:hover {
  background: #00e63a;
  text-decoration: none;
  transform: translateY(-1px);
  box-shadow: 0 0 28px rgba(0,255,65,.3);
}

.btn-secondary {
  background: var(--bg-card2);
  color: var(--text-primary);
  border: 1px solid var(--border);
  padding: .65rem 1.4rem;
  font-size: .9rem;
}
.btn-secondary:hover { background: var(--bg-card-hover); text-decoration: none; border-color: var(--text-muted); }

.btn-sm { padding: .4rem .9rem; font-size: .8rem; }

/* ── Section wrapper ────────────────────────────────────── */
.section {
  max-width: 1280px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
}

.section-title {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--text-white);
  margin-bottom: .5rem;
}
.section-sub {
  font-size: .9rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

/* ── Filter / Sort Bar ──────────────────────────────────── */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .75rem;
  margin-bottom: 1.75rem;
}

.filter-group { display: flex; gap: .5rem; flex-wrap: wrap; }

.filter-btn {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: .4rem 1rem;
  border-radius: var(--radius);
  font-size: .8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all .18s;
}
.filter-btn:hover { color: var(--text-primary); border-color: var(--text-muted); }
.filter-btn.active {
  background: rgba(0,255,65,.1);
  border-color: var(--accent-green2);
  color: var(--accent-green2);
}

.sort-select {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: .4rem .8rem;
  border-radius: var(--radius);
  font-size: .8rem;
  cursor: pointer;
  outline: none;
  margin-left: auto;
}
.sort-select:focus { border-color: var(--accent-blue); }

/* ── Puzzle Grid ────────────────────────────────────────── */
.puzzle-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.puzzle-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  cursor: pointer;
  transition: all .2s;
  position: relative;
  overflow: hidden;
}
.puzzle-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-green), transparent);
  opacity: 0;
  transition: opacity .2s;
}
.puzzle-card:hover {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  text-decoration: none;
}
.puzzle-card:hover::before { opacity: 1; }

.card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: .75rem;
}
.card-num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-white);
  line-height: 1;
}
.card-bits {
  font-family: var(--font-mono);
  font-size: .7rem;
  color: var(--text-secondary);
  margin-top: .2rem;
}

/* Status Badges */
.badge {
  display: inline-flex;
  align-items: center;
  gap: .3rem;
  padding: .2rem .65rem;
  border-radius: var(--radius);
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .04em;
  text-transform: uppercase;
}
.badge-solved   { background: rgba(57,211,83,.12);  color: var(--accent-green2); border: 1px solid rgba(57,211,83,.25); }
.badge-unsolved { background: rgba(88,166,255,.1);  color: var(--accent-blue);   border: 1px solid rgba(88,166,255,.2); }
.badge-progress { background: rgba(227,179,65,.1);  color: var(--accent-yellow); border: 1px solid rgba(227,179,65,.2); }

.badge-dot { width: 5px; height: 5px; border-radius: 50%; background: currentColor; }
.badge-solved .badge-dot { animation: pulse 2s infinite; }

.card-meta {
  display: flex;
  gap: 1rem;
  font-size: .78rem;
  color: var(--text-secondary);
  margin-top: .75rem;
}

.card-meta-item { display: flex; align-items: center; gap: .3rem; }

/* Score bar */
.score-bar-wrap { margin-top: .75rem; }
.score-bar-label {
  display: flex; justify-content: space-between;
  font-size: .7rem; color: var(--text-secondary);
  margin-bottom: .3rem;
}
.score-bar {
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}
.score-fill {
  height: 100%;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent-green), var(--accent-blue));
  transition: width .5s ease;
}

/* ── Cards skeleton ─────────────────────────────────────── */
.skeleton {
  background: linear-gradient(90deg, var(--bg-card) 25%, var(--bg-card2) 50%, var(--bg-card) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-sm);
}

/* ── About Section ──────────────────────────────────────── */
.about-section {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 4rem 1.5rem;
}
.about-inner {
  max-width: 800px;
  margin: 0 auto;
}
.about-section h2 { font-size: 1.5rem; font-weight: 600; color: var(--text-white); margin-bottom: 1rem; }
.about-section p  { color: var(--text-secondary); margin-bottom: .75rem; line-height: 1.8; }
.disclaimer {
  margin-top: 1.5rem;
  padding: .85rem 1.1rem;
  background: rgba(247,129,102,.06);
  border: 1px solid rgba(247,129,102,.2);
  border-radius: var(--radius);
  font-size: .8rem;
  color: var(--accent-orange);
}

/* ── Footer ─────────────────────────────────────────────── */
footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem;
  text-align: center;
  font-size: .8rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}
footer a { color: var(--text-muted); }
footer a:hover { color: var(--text-secondary); }

/* ── Rankings Table ─────────────────────────────────────── */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}
table {
  width: 100%;
  border-collapse: collapse;
}
thead tr {
  background: var(--bg-card2);
  border-bottom: 1px solid var(--border);
}
th {
  padding: .85rem 1rem;
  text-align: left;
  font-size: .75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-secondary);
  white-space: nowrap;
  cursor: pointer;
  user-select: none;
  transition: color .15s;
}
th:hover { color: var(--text-primary); }
th .sort-arrow { opacity: .5; margin-left: .3rem; }
th.sorted .sort-arrow { opacity: 1; color: var(--accent-blue); }

tbody tr {
  border-bottom: 1px solid var(--border-light);
  transition: background .15s;
  cursor: pointer;
}
tbody tr:hover { background: var(--bg-card-hover); }
tbody tr:last-child { border-bottom: none; }

td {
  padding: .75rem 1rem;
  font-size: .875rem;
  color: var(--text-primary);
}

.rank-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1rem;
  color: var(--text-secondary);
}
.rank-num.top1 { color: var(--accent-yellow); }
.rank-num.top2 { color: #c0c0c0; }
.rank-num.top3 { color: #cd7f32; }

/* Rank tier badges */
.tier-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px; height: 28px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: .85rem;
  font-family: var(--font-mono);
}
.tier-S { background: rgba(255,107,107,.15); color: var(--rank-s); border: 1px solid rgba(255,107,107,.3); }
.tier-A { background: rgba(255,159,67,.12); color: var(--rank-a); border: 1px solid rgba(255,159,67,.25); }
.tier-B { background: rgba(255,211,42,.1);  color: var(--rank-b); border: 1px solid rgba(255,211,42,.2); }
.tier-C { background: rgba(88,166,255,.1);  color: var(--rank-c); border: 1px solid rgba(88,166,255,.2); }
.tier-D { background: rgba(139,148,158,.08); color: var(--rank-d); border: 1px solid rgba(139,148,158,.15); }

/* Score cell */
.score-cell {
  font-family: var(--font-mono);
  font-size: .85rem;
  font-weight: 600;
}
.score-mini-bar {
  height: 3px;
  background: var(--border);
  border-radius: 2px;
  margin-top: .25rem;
  overflow: hidden;
}
.score-mini-fill {
  height: 100%;
  border-radius: 2px;
  background: var(--accent-green2);
}

/* ── Puzzle Detail: Layout ──────────────────────────────── */
.detail-layout {
  max-width: 1280px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 1.5rem;
  align-items: start;
}

@media (max-width: 900px) {
  .detail-layout { grid-template-columns: 1fr; }
}

/* Puzzle header */
.puzzle-header {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  margin-bottom: 1.5rem;
}

.puzzle-header-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.puzzle-title-group h1 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-white);
  line-height: 1;
  margin-bottom: .4rem;
}

.puzzle-address {
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--text-secondary);
  word-break: break-all;
  max-width: 420px;
}

.puzzle-range {
  display: flex;
  align-items: center;
  gap: .75rem;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--text-secondary);
}
.range-arrow { color: var(--text-muted); }

.puzzle-updated { font-size: .75rem; color: var(--text-muted); }

/* ── Tabs ───────────────────────────────────────────────── */
.tab-bar {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
  overflow-x: auto;
}

.tab-btn {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-secondary);
  padding: .75rem 1.25rem;
  font-size: .875rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: all .15s;
  display: flex;
  align-items: center;
  gap: .4rem;
}
.tab-btn:hover { color: var(--text-primary); }
.tab-btn.active {
  color: var(--accent-blue);
  border-bottom-color: var(--accent-blue);
}

.tab-count {
  background: var(--bg-card2);
  color: var(--text-secondary);
  font-size: .7rem;
  padding: .1rem .45rem;
  border-radius: 999px;
}
.tab-btn.active .tab-count { background: rgba(88,166,255,.15); color: var(--accent-blue); }

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

/* ── Clue List ──────────────────────────────────────────── */
.clue-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: .6rem;
  transition: border-color .15s;
}
.clue-item:hover { border-color: var(--text-muted); }

.clue-header {
  display: flex;
  align-items: center;
  gap: .75rem;
  flex-wrap: wrap;
  margin-bottom: .5rem;
}
.clue-type {
  background: rgba(88,166,255,.1);
  color: var(--accent-blue);
  border: 1px solid rgba(88,166,255,.2);
  font-size: .7rem;
  font-family: var(--font-mono);
  padding: .15rem .5rem;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: .04em;
}
.clue-value { font-family: var(--font-mono); font-size: .85rem; color: var(--text-primary); }
.clue-confidence {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: .4rem;
  font-size: .75rem;
  color: var(--text-secondary);
}
.conf-bar {
  width: 60px; height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}
.conf-fill { height: 100%; border-radius: 2px; }
.conf-high   { background: var(--accent-green2); }
.conf-medium { background: var(--accent-yellow); }
.conf-low    { background: var(--accent-orange); }

.clue-footer {
  display: flex;
  align-items: center;
  gap: .75rem;
  font-size: .75rem;
  color: var(--text-secondary);
}

.useful-toggle {
  display: inline-flex;
  align-items: center;
  gap: .3rem;
  background: none;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: .2rem .6rem;
  border-radius: var(--radius-sm);
  font-size: .72rem;
  cursor: pointer;
  transition: all .15s;
}
.useful-toggle.active {
  background: rgba(57,211,83,.1);
  border-color: var(--accent-green2);
  color: var(--accent-green2);
}
.useful-toggle:hover { border-color: var(--text-muted); color: var(--text-primary); }

/* ── Sources ────────────────────────────────────────────── */
.source-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: .6rem;
}
.source-title { font-weight: 600; color: var(--text-white); margin-bottom: .25rem; }
.source-preview { font-size: .82rem; color: var(--text-secondary); display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }

/* ── Notes ──────────────────────────────────────────────── */
.note-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: .6rem;
  position: relative;
}
.note-item.pinned {
  border-color: rgba(227,179,65,.3);
  background: rgba(227,179,65,.04);
}
.note-pin-badge {
  position: absolute;
  top: .75rem; right: .75rem;
  font-size: .65rem;
  color: var(--accent-yellow);
  font-family: var(--font-mono);
}
.note-text { font-size: .875rem; line-height: 1.7; color: var(--text-primary); }
.note-meta { font-size: .72rem; color: var(--text-secondary); margin-top: .5rem; }

.note-form {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}
.note-form textarea {
  width: 100%;
  background: var(--bg-base);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: .875rem;
  padding: .75rem;
  resize: vertical;
  min-height: 80px;
  outline: none;
  transition: border-color .15s;
}
.note-form textarea:focus { border-color: var(--accent-blue); }
.note-form-footer {
  display: flex;
  justify-content: flex-end;
  gap: .75rem;
  margin-top: .75rem;
}

/* ── History Timeline ───────────────────────────────────── */
.timeline { position: relative; }
.timeline::before {
  content: '';
  position: absolute;
  left: 9px; top: 0; bottom: 0;
  width: 2px;
  background: var(--border);
}
.timeline-item {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.5rem;
  position: relative;
}
.timeline-dot {
  width: 20px; height: 20px;
  min-width: 20px;
  background: var(--bg-card2);
  border: 2px solid var(--border);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: .55rem;
  position: relative;
  z-index: 1;
}
.timeline-dot.green { border-color: var(--accent-green2); background: rgba(57,211,83,.1); }
.timeline-content .event-label { font-weight: 600; font-size: .875rem; color: var(--text-primary); }
.timeline-content .event-meta  { font-size: .75rem; color: var(--text-secondary); margin-top: .2rem; }

/* ── Sidebar ────────────────────────────────────────────── */
.sidebar > * + * { margin-top: 1rem; }

.sidebar-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
}
.sidebar-card h3 {
  font-size: .8rem;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.stat-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: .4rem 0;
  border-bottom: 1px solid var(--border-light);
  font-size: .85rem;
}
.stat-row:last-child { border-bottom: none; }
.stat-row-label { color: var(--text-secondary); }
.stat-row-val { font-family: var(--font-mono); font-weight: 600; color: var(--text-primary); }

.ranking-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: .5rem 0;
  border-bottom: 1px solid var(--border-light);
  font-size: .82rem;
}
.ranking-row:last-child { border-bottom: none; }
.ranking-label { color: var(--text-secondary); flex: 1; }
.ranking-score-val {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--text-primary);
  text-align: right;
  width: 36px;
}
.ranking-mini-bar {
  width: 60px; height: 3px;
  background: var(--border);
  border-radius: 2px;
  margin-left: .75rem;
  overflow: hidden;
}
.ranking-mini-fill {
  height: 100%;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent-green), var(--accent-blue));
}

.related-puzzle {
  display: flex;
  align-items: center;
  gap: .75rem;
  padding: .5rem .6rem;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background .15s;
  text-decoration: none;
}
.related-puzzle:hover { background: var(--bg-card2); text-decoration: none; }
.related-num { font-family: var(--font-mono); font-weight: 700; color: var(--text-white); font-size: .95rem; width: 24px; }
.related-bits { font-size: .75rem; color: var(--text-secondary); }
.related-score { font-family: var(--font-mono); font-size: .78rem; color: var(--accent-blue); margin-left: auto; }

/* ── Animations ─────────────────────────────────────────── */
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .4; }
}

@keyframes shimmer {
  0%   { background-position: -200% 0; }
  100% { background-position:  200% 0; }
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.fade-in { animation: fadeIn .3s ease forwards; }

/* ── Loading State ──────────────────────────────────────── */
.loading-spinner {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4rem;
  color: var(--text-muted);
  gap: .75rem;
  font-size: .875rem;
}
.spinner {
  width: 20px; height: 20px;
  border: 2px solid var(--border);
  border-top-color: var(--accent-green);
  border-radius: 50%;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.empty-state {
  text-align: center;
  padding: 3rem 1.5rem;
  color: var(--text-secondary);
}
.empty-state .empty-icon { font-size: 2.5rem; margin-bottom: 1rem; opacity: .4; }
.empty-state p { font-size: .9rem; }

/* ── Notification Toast ─────────────────────────────────── */
#toast {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: .75rem 1.1rem;
  font-size: .85rem;
  color: var(--text-primary);
  box-shadow: var(--shadow-lg);
  z-index: 9999;
  opacity: 0;
  transform: translateY(8px);
  transition: all .25s;
  pointer-events: none;
}
#toast.show { opacity: 1; transform: translateY(0); }
#toast.success { border-color: var(--accent-green2); color: var(--accent-green2); }
#toast.error   { border-color: var(--accent-orange); color: var(--accent-orange); }

/* ── Responsive ─────────────────────────────────────────── */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .hero { padding: 3rem 1rem 2.5rem; }
  .stats-bar { gap: .75rem 1.25rem; }
  .puzzle-grid { grid-template-columns: 1fr; }
  .filter-bar { flex-direction: column; align-items: stretch; }
  .sort-select { margin-left: 0; }
  .detail-layout { padding: 1rem; }
  .puzzle-header { padding: 1.25rem; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.75rem; }
  .tab-btn { padding: .6rem .85rem; font-size: .8rem; }
}

/* ── Hamburger Menu ──────────────────────────────────────── */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 6px;
  border-radius: var(--radius-sm);
}
.nav-hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: transform .25s, opacity .2s;
}
.nav-hamburger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-hamburger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

@media (max-width: 768px) {
  .nav-hamburger { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background: rgba(13,17,23,.98);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 0;
    backdrop-filter: blur(12px);
  }
  .nav-links.open {
    display: flex;
  }
  .nav-links li { list-style: none; }
  .nav-links li a {
    display: block;
    padding: .75rem 0;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-primary);
    font-size: .95rem;
  }
  .nav-links li:last-child a { border-bottom: none; }
}

/* ── Page Transition / Fade-in ───────────────────────────── */
@keyframes pageFadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}
main, .hero, .puzzle-grid-section, .about-section, .detail-layout, .page-body {
  animation: pageFadeIn .3s ease both;
}

/* ── Card hover lift ─────────────────────────────────────── */
.puzzle-card {
  transition: border-color .18s, box-shadow .18s, transform .18s;
}
.puzzle-card:hover {
  box-shadow: var(--shadow-lg), var(--glow-green);
  transform: translateY(-3px);
}

/* ── Button press state ─────────────────────────────────────*/
.btn:active, .filter-btn:active, .tab-btn:active {
  transform: scale(0.97);
  opacity: .85;
}

/* ── Skeleton Shimmer improvement ───────────────────────── */
.skeleton {
  background: linear-gradient(90deg, var(--bg-card) 25%, var(--bg-card2) 50%, var(--bg-card) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.4s infinite;
}
@keyframes shimmer {
  0%   { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}