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

:root {
  --bg:          #0f1117;
  --surface:     #181c27;
  --surface-2:   #1e2333;
  --border:      #2a3045;
  --accent:      #6c63ff;
  --accent-glow: rgba(108, 99, 255, 0.35);
  --accent-2:    #ff6584;
  --success:     #43d98c;
  --success-glow:rgba(67, 217, 140, 0.35);
  --warn:        #ffb347;
  --text:        #e8eaf0;
  --text-muted:  #7a849e;
  --text-dim:    #4a5268;
  --radius:      10px;
  --radius-sm:   6px;
  --font:        'Segoe UI', system-ui, -apple-system, sans-serif;
  --transition:  0.18s ease;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* ─── Loading Screen ────────────────────────────────────────────────────────── */
#loading-screen {
  position: fixed; inset: 0;
  background: var(--bg);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000;
  transition: opacity 0.5s ease;
}
#loading-screen.fade-out { opacity: 0; pointer-events: none; }

.loading-inner {
  display: flex; flex-direction: column; align-items: center; gap: 20px;
  width: 320px;
}
.loading-logo {
  font-size: 28px; font-weight: 700; letter-spacing: -0.5px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.loading-bar-track {
  width: 100%; height: 4px;
  background: var(--surface-2);
  border-radius: 2px; overflow: hidden;
}
.loading-bar-fill {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 2px;
  transition: width 0.3s ease;
}
.loading-label {
  font-size: 13px; color: var(--text-muted);
}

/* ─── Fanfare Overlay ────────────────────────────────────────────────────────── */
#fanfare-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.75);
  display: flex; align-items: center; justify-content: center;
  z-index: 900;
  animation: fadeIn 0.25s ease;
}
#fanfare-overlay.hidden { display: none; }

@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

.fanfare-burst {
  position: absolute; inset: 0;
  pointer-events: none;
  overflow: hidden;
}
/* Particle stars injected via JS */
.fanfare-star {
  position: absolute;
  width: 8px; height: 8px;
  border-radius: 50%;
  animation: starBurst 0.9s ease-out forwards;
}
@keyframes starBurst {
  0%   { transform: translate(0,0) scale(1); opacity: 1; }
  100% { transform: translate(var(--dx), var(--dy)) scale(0); opacity: 0; }
}

.fanfare-content {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--accent);
  border-radius: 16px;
  padding: 48px 56px;
  text-align: center;
  box-shadow: 0 0 60px var(--accent-glow), 0 24px 48px rgba(0,0,0,0.5);
  animation: popIn 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes popIn {
  from { transform: scale(0.7); opacity: 0; }
  to   { transform: scale(1);   opacity: 1; }
}
.fanfare-title {
  font-size: 13px; font-weight: 600; letter-spacing: 2px; text-transform: uppercase;
  color: var(--accent); margin-bottom: 16px;
}
.fanfare-word {
  font-size: 52px; font-weight: 800; letter-spacing: -1px;
  background: linear-gradient(135deg, var(--success), var(--accent));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 32px;
  animation: wordPulse 0.6s ease;
}
@keyframes wordPulse {
  0%   { transform: scale(0.5); }
  70%  { transform: scale(1.1); }
  100% { transform: scale(1); }
}
.fanfare-close {
  background: var(--accent);
  color: #fff; border: none; border-radius: var(--radius-sm);
  padding: 10px 28px; font-size: 14px; font-weight: 600;
  cursor: pointer; transition: background var(--transition), transform var(--transition);
}
.fanfare-close:hover { background: #7b73ff; transform: translateY(-1px); }

/* ─── App Layout ─────────────────────────────────────────────────────────────── */
#app { min-height: 100vh; max-width: 1200px; margin: 0 auto; padding: 28px 24px 60px; }
#app.hidden { display: none; }

header {
  display: flex; align-items: flex-start; justify-content: space-between;
  margin-bottom: 32px;
}
header h1 {
  font-size: 26px; font-weight: 800; letter-spacing: -0.5px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.subtitle { font-size: 13px; color: var(--text-muted); margin-top: 2px; }

/* ─── Goals ──────────────────────────────────────────────────────────────────── */
.goals-section { margin-bottom: 28px; }
.goals-row {
  display: flex; gap: 14px; margin-top: 10px; flex-wrap: wrap;
}
.goal-card {
  flex: 1; min-width: 140px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  transition: border-color var(--transition), box-shadow var(--transition);
  position: relative; overflow: hidden;
}
.goal-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, var(--accent-glow), transparent);
  opacity: 0; transition: opacity var(--transition);
}
.goal-card.completed { border-color: var(--success); }
.goal-card.completed::before { opacity: 1; background: linear-gradient(135deg, var(--success-glow), transparent); }
.goal-card.completed .goal-icon { color: var(--success); }
.goal-card.completed .goal-status { color: var(--success); }

.goal-icon { font-size: 22px; }
.goal-name { font-size: 15px; font-weight: 700; }
.goal-status { font-size: 11px; color: var(--text-dim); text-transform: uppercase; letter-spacing: 1px; }

@keyframes goalComplete {
  0%   { transform: scale(1); }
  30%  { transform: scale(1.06); }
  60%  { transform: scale(0.97); }
  100% { transform: scale(1); }
}
.goal-card.completing { animation: goalComplete 0.5s ease; }

/* ─── Main Grid ──────────────────────────────────────────────────────────────── */
.main-grid {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 20px;
  align-items: start;
}
@media (max-width: 820px) {
  .main-grid { grid-template-columns: 1fr; }
}

/* ─── Panels ─────────────────────────────────────────────────────────────────── */
.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.panel-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
}
.section-label {
  font-size: 11px; font-weight: 700; letter-spacing: 1.5px;
  text-transform: uppercase; color: var(--text-muted);
}
.word-count, .history-count {
  font-size: 12px; color: var(--text-dim);
}

/* ─── Words Grid ─────────────────────────────────────────────────────────────── */
.words-grid {
  display: flex; flex-wrap: wrap; gap: 8px;
  padding: 16px;
  max-height: 400px; overflow-y: auto;
}
.words-grid::-webkit-scrollbar { width: 4px; }
.words-grid::-webkit-scrollbar-track { background: transparent; }
.words-grid::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.word-chip {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 5px 14px;
  font-size: 13px; font-weight: 500;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition),
              transform var(--transition), box-shadow var(--transition);
  user-select: none;
}
.word-chip:hover {
  background: var(--surface);
  border-color: var(--accent);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}
.word-chip.in-slot {
  background: rgba(108,99,255,0.15);
  border-color: var(--accent);
  color: #a8a3ff;
}
.word-chip.new-unlock {
  animation: unlockPop 0.55s cubic-bezier(0.34, 1.56, 0.64, 1);
  border-color: var(--success);
  box-shadow: 0 0 16px var(--success-glow);
}
@keyframes unlockPop {
  0%   { transform: scale(0); opacity: 0; }
  60%  { transform: scale(1.15); }
  100% { transform: scale(1); opacity: 1; }
}

/* ─── Right Column ───────────────────────────────────────────────────────────── */
.right-column { display: flex; flex-direction: column; gap: 20px; }

/* ─── Combine Panel ──────────────────────────────────────────────────────────── */
.combine-slots {
  padding: 16px;
  min-height: 64px;
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
}
.slots-placeholder {
  font-size: 13px; color: var(--text-dim); font-style: italic;
}
.slot-chip {
  display: flex; align-items: center; gap: 0;
  border-radius: 20px; overflow: hidden;
  border: 1px solid var(--border);
  font-size: 13px; font-weight: 500;
  animation: chipIn 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes chipIn {
  from { transform: scale(0.5); opacity: 0; }
  to   { transform: scale(1);   opacity: 1; }
}
.slot-sign {
  padding: 5px 10px;
  font-weight: 700; font-size: 15px;
  cursor: pointer; user-select: none;
  transition: background var(--transition), color var(--transition);
  min-width: 32px; text-align: center;
}
.slot-sign.plus  { background: rgba(67,217,140,0.2);  color: var(--success); }
.slot-sign.minus { background: rgba(255,101,132,0.2); color: var(--accent-2); }
.slot-sign:hover { filter: brightness(1.2); }

.slot-label {
  padding: 5px 10px;
  background: var(--surface-2);
}
.slot-remove {
  padding: 5px 9px;
  background: var(--surface-2);
  color: var(--text-dim); cursor: pointer;
  transition: color var(--transition), background var(--transition);
  border-left: 1px solid var(--border);
}
.slot-remove:hover { color: var(--accent-2); background: rgba(255,101,132,0.1); }

.combine-actions {
  display: flex; gap: 10px; padding: 0 16px 16px;
}
.btn-primary {
  flex: 1;
  background: var(--accent); color: #fff;
  border: none; border-radius: var(--radius-sm);
  padding: 10px 20px; font-size: 14px; font-weight: 700;
  cursor: pointer; letter-spacing: 0.3px;
  transition: background var(--transition), transform var(--transition),
              box-shadow var(--transition), opacity var(--transition);
}
.btn-primary:not(:disabled):hover {
  background: #7b73ff;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px var(--accent-glow);
}
.btn-primary:not(:disabled):active {
  transform: translateY(0);
  box-shadow: none;
}
.btn-primary:disabled { opacity: 0.35; cursor: not-allowed; }
.btn-primary.pulse {
  animation: combinePulse 0.4s ease;
}
@keyframes combinePulse {
  0%   { box-shadow: 0 0 0 0 var(--accent-glow); }
  50%  { box-shadow: 0 0 0 12px transparent; }
  100% { box-shadow: 0 0 0 0 transparent; }
}

.btn-secondary {
  background: var(--surface-2);
  color: var(--text-muted); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 10px 16px;
  font-size: 14px; font-weight: 600;
  cursor: pointer; transition: background var(--transition), color var(--transition);
}
.btn-secondary:hover { background: var(--border); color: var(--text); }

.btn-reset {
  background: transparent; color: var(--text-dim);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 7px 14px; font-size: 12px; font-weight: 600;
  cursor: pointer; letter-spacing: 0.3px;
  transition: color var(--transition), border-color var(--transition);
}
.btn-reset:hover { color: var(--accent-2); border-color: var(--accent-2); }

.combine-result {
  margin: 0 16px 16px;
  border-radius: var(--radius-sm);
  font-size: 13px; font-weight: 500;
  min-height: 0; overflow: hidden;
  transition: all 0.3s ease;
}
.combine-result.show {
  padding: 10px 14px;
}
.combine-result.result-new {
  background: rgba(67,217,140,0.1);
  border: 1px solid rgba(67,217,140,0.3);
  color: var(--success);
  animation: resultSlide 0.3s ease;
}
.combine-result.result-known {
  background: rgba(108,99,255,0.1);
  border: 1px solid rgba(108,99,255,0.3);
  color: #a8a3ff;
  animation: resultSlide 0.3s ease;
}
.combine-result.result-error {
  background: rgba(255,101,132,0.1);
  border: 1px solid rgba(255,101,132,0.3);
  color: var(--accent-2);
  animation: resultSlide 0.3s ease;
}
@keyframes resultSlide {
  from { transform: translateY(-6px); opacity: 0; }
  to   { transform: translateY(0);    opacity: 1; }
}

/* ─── History ─────────────────────────────────────────────────────────────────── */
.panel-history { max-height: 380px; display: flex; flex-direction: column; }
.history-list {
  overflow-y: auto; flex: 1;
  padding: 8px 0;
}
.history-list::-webkit-scrollbar { width: 4px; }
.history-list::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.history-empty {
  padding: 24px; text-align: center;
  font-size: 13px; color: var(--text-dim); font-style: italic;
}
.history-item {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 18px;
  border-bottom: 1px solid rgba(42,48,69,0.5);
  font-size: 13px;
  animation: historyIn 0.2s ease;
}
@keyframes historyIn {
  from { opacity: 0; transform: translateX(8px); }
  to   { opacity: 1; transform: translateX(0); }
}
.history-item:last-child { border-bottom: none; }
.history-formula { color: var(--text-muted); flex: 1; }
.history-formula .op-plus  { color: var(--success); font-weight: 700; }
.history-formula .op-minus { color: var(--accent-2); font-weight: 700; }
.history-arrow { color: var(--text-dim); }
.history-result { font-weight: 600; }
.history-result.is-new { color: var(--success); }
.history-result.is-known { color: var(--accent); }

/* ─── Reset Dialog ────────────────────────────────────────────────────────────── */
.dialog-backdrop {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.6);
  display: flex; align-items: center; justify-content: center;
  z-index: 800;
  animation: fadeIn 0.2s ease;
}
.dialog-backdrop.hidden { display: none; }
.dialog {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 32px;
  width: 340px;
  box-shadow: 0 24px 48px rgba(0,0,0,0.5);
  animation: popIn 0.25s ease;
}
.dialog-title { font-size: 17px; font-weight: 700; margin-bottom: 10px; }
.dialog-body  { font-size: 13px; color: var(--text-muted); margin-bottom: 24px; }
.dialog-actions { display: flex; gap: 10px; justify-content: flex-end; }
.btn-danger {
  background: var(--accent-2); color: #fff;
  border: none; border-radius: var(--radius-sm);
  padding: 9px 20px; font-size: 14px; font-weight: 600;
  cursor: pointer; transition: background var(--transition);
}
.btn-danger:hover { background: #ff4d6d; }