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

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

:root {
  --bg: #0d0d0f;
  --surface: #141417;
  --surface-hover: #1a1a1f;
  --border: #1e1e24;
  --border-hover: #2e2e3a;
  --text-primary: #e8e8f0;
  --text-secondary: #6b6b80;
  --text-muted: #3f3f50;
  --accent-blue: #5b8def;
}

body.light {
  --bg: #f5f5f7;
  --surface: #ffffff;
  --surface-hover: #f0f0f5;
  --border: #dcdce4;
  --border-hover: #c0c0cc;
  --text-primary: #1a1a2e;
  --text-secondary: #5a5a72;
  --text-muted: #9090a8;
  --accent-blue: #3a6fd8;
}

body.light body::before {
  background-image:
    linear-gradient(rgba(0,0,0,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,0,0,0.03) 1px, transparent 1px);
}

.theme-btn {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 6px 16px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
  position: fixed;
  top: 20px;
  right: 24px;
  z-index: 100;
}

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

html, body { height: 100%; }

body {
  background: var(--bg);
  color: var(--text-primary);
  font-family: 'Sora', sans-serif;
  min-height: 100vh;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.013) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.013) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: 0;
}

.page {
  position: relative;
  z-index: 1;
  max-width: 860px;
  margin: 0 auto;
  padding: 52px 24px 80px;
}

.header { margin-bottom: 40px; }

.breadcrumb {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.breadcrumb span { color: var(--text-secondary); }

.breadcrumb a {
  color: var(--text-muted);
  text-decoration: none;
}

.breadcrumb a:hover { color: var(--text-secondary); }

h1 {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  line-height: 1.1;
  margin-bottom: 10px;
}

.stats-bar {
  display: flex;
  gap: 20px;
  margin: 28px 0 32px;
  padding: 14px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
}

.stat {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12.5px;
  color: var(--text-secondary);
}

.stat-count {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
}

.filter-bar {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}

.filter-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.filter-btn {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 6px 16px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
}

.filter-btn:hover { border-color: var(--text-muted); color: var(--text-primary); }

.filter-btn.active {
  background: var(--surface);
  border-color: var(--accent-blue);
  color: var(--accent-blue);
}

.filter-select {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
}

.filter-select:hover { border-color: var(--text-muted); color: var(--text-primary); }

.filter-select option { background: var(--surface); color: var(--text-primary); }

.filter-divider {
  width: 1px;
  height: 20px;
  background: var(--border);
  margin: 0 4px;
}

.table-head {
  display: grid;
  grid-template-columns: 48px 80px 1fr 70px 52px;
  gap: 12px;
  padding: 10px 16px;
  font-size: 11px;
  font-family: 'JetBrains Mono', monospace;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
}

.problem-list { list-style: none; }

.problem-row {
  display: grid;
  grid-template-columns: 48px 80px 1fr 70px 52px;
  gap: 12px;
  align-items: center;
  padding: 0 16px;
  border-bottom: 1px solid var(--border);
  transition: background 0.15s ease;
  min-height: 52px;
  text-decoration: none;
  color: inherit;
}

.diff-circle {
    display: inline-block;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    border-style: solid;
    border-width: 1px;
    flex-shrink: 0;
}

.prob-number {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--text-muted);
}

.prob-id {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--text-secondary);
}

.prob-title {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: color 0.15s;
}

.problem-row:hover .prob-title { color: var(--accent-blue) !important; }

.prob-difficulty {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--text-secondary);
  text-align: right;
}

.user-bar {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
}

.user-input {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-primary);
  outline: none;
  transition: border-color 0.15s ease;
  width: 200px;
}

.user-input::placeholder { color: var(--text-muted); }

.user-input:focus { border-color: var(--accent-blue); }

.fetch-btn {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 6px 16px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
}

.fetch-btn:not(:disabled):hover {
  border-color: var(--accent-blue);
  color: var(--accent-blue);
}

.fetch-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.filter-select:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.prob-title-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  overflow: hidden;
  min-width: 0;
}

.filter-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.filter-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  align-self: center;
}

.filter-input {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-primary);
  outline: none;
  transition: border-color 0.15s ease;
  width: 150px;
}

.filter-input::placeholder { color: var(--text-muted); }
.filter-input:focus { border-color: var(--accent-blue); }

.filter-input::-webkit-outer-spin-button,
.filter-input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.filter-input[type=number] {
  -moz-appearance: textfield;
}