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

:root {
  --bg: #0d0d0d;
  --surface: #1a1a1a;
  --surface2: #222;
  --accent: #e63946;
  --accent2: #ff6b6b;
  --gold: #f4c430;
  --silver: #c0c0c0;
  --bronze: #cd7f32;
  --text: #f0f0f0;
  --muted: #888;
  --border: #2e2e2e;
  --radius: 10px;
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===== Header ===== */
header {
  background: linear-gradient(135deg, #1a0a0a 0%, #1a1a1a 60%, #0d0d0d 100%);
  border-bottom: 2px solid var(--accent);
  padding: 2rem 1.5rem 1.5rem;
  text-align: center;
}

.header-inner h1 {
  font-size: clamp(2rem, 6vw, 3.5rem);
  font-weight: 900;
  letter-spacing: -1px;
  text-transform: uppercase;
}

.header-inner h1 span {
  color: var(--accent);
  font-style: italic;
}

.subtitle {
  color: var(--muted);
  font-size: 0.9rem;
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-top: 0.4rem;
}

/* ===== Main layout ===== */
main {
  flex: 1;
  max-width: 900px;
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* ===== Year Tabs ===== */
.year-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
}

.year-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 6px;
  padding: 0.45rem 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}

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

.year-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

/* ===== Month Grid ===== */
.month-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

@media (max-width: 480px) {
  .month-grid { grid-template-columns: repeat(4, 1fr); }
}

.month-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 6px;
  padding: 0.5rem 0.25rem;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  text-align: center;
  transition: all 0.15s ease;
}

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

.month-btn.active {
  background: var(--surface2);
  border-color: var(--accent);
  color: var(--accent);
}

/* ===== Chart meta bar ===== */
.chart-meta {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.6rem 1rem;
  margin-bottom: 1.25rem;
  font-size: 0.8rem;
  color: var(--muted);
  letter-spacing: 1px;
  text-transform: uppercase;
}

/* ===== Placeholder ===== */
.placeholder {
  text-align: center;
  padding: 4rem 1rem;
  color: var(--muted);
}

.placeholder-icon {
  font-size: 4rem;
  opacity: 0.2;
  margin-bottom: 1rem;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.15; }
  50% { opacity: 0.35; }
}

/* ===== Song List ===== */
.song-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.song-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  transition: transform 0.15s ease, border-color 0.15s ease;
  animation: fadeUp 0.3s ease both;
}

.song-card:hover {
  transform: translateX(4px);
  border-color: #3a3a3a;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Stagger animation */
.song-card:nth-child(1)  { animation-delay: 0.00s; }
.song-card:nth-child(2)  { animation-delay: 0.04s; }
.song-card:nth-child(3)  { animation-delay: 0.08s; }
.song-card:nth-child(4)  { animation-delay: 0.12s; }
.song-card:nth-child(5)  { animation-delay: 0.16s; }
.song-card:nth-child(6)  { animation-delay: 0.20s; }
.song-card:nth-child(7)  { animation-delay: 0.24s; }
.song-card:nth-child(8)  { animation-delay: 0.28s; }
.song-card:nth-child(9)  { animation-delay: 0.32s; }
.song-card:nth-child(10) { animation-delay: 0.36s; }

/* Rank number */
.rank {
  font-size: 1.4rem;
  font-weight: 900;
  min-width: 2.5rem;
  text-align: center;
  flex-shrink: 0;
}

.rank-1 { color: var(--gold); }
.rank-2 { color: var(--silver); }
.rank-3 { color: var(--bronze); }
.rank-4, .rank-5, .rank-6,
.rank-7, .rank-8, .rank-9, .rank-10 { color: var(--muted); }

/* Album art */
.cover {
  width: 52px;
  height: 52px;
  border-radius: 6px;
  object-fit: cover;
  flex-shrink: 0;
  background: var(--surface2);
}

.cover-placeholder {
  width: 52px;
  height: 52px;
  border-radius: 6px;
  background: var(--surface2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  flex-shrink: 0;
  color: var(--border);
}

/* Song info */
.song-info {
  flex: 1;
  min-width: 0;
}

.song-title {
  font-weight: 700;
  font-size: 1rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.song-artist {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.2rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Stats badges */
.song-stats {
  display: flex;
  gap: 0.5rem;
  flex-shrink: 0;
}

.badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  text-align: center;
  line-height: 1.3;
}

.badge-peak {
  background: rgba(230, 57, 70, 0.15);
  border: 1px solid rgba(230, 57, 70, 0.3);
  color: var(--accent2);
}

.badge-weeks {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border);
  color: var(--muted);
}

@media (max-width: 520px) {
  .song-stats { display: none; }
}

/* ===== Loading spinner ===== */
.loading {
  text-align: center;
  padding: 3rem;
  color: var(--muted);
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin: 0 auto 1rem;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--muted);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
}

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