/* ─── Custom Properties ─────────────────────────────────── */
:root {
  --primary: #6c63ff;
  --primary-dark: #5a52e0;
  --surface: #ffffff;
  --surface-alt: #f8f7ff;
  --text: #1a1a2e;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --locked-bg: #f3f4f6;
  --locked-text: #9ca3af;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  --radius: 12px;
  --radius-sm: 8px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--surface-alt);
  color: var(--text);
  min-height: 100vh;
  padding: 1.5rem;
}

/* ─── Page Layout ───────────────────────────────────────── */
.achievements-page {
  max-width: 960px;
  margin: 0 auto;
}

.page-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 2rem;
}

.back-link {
  color: var(--primary);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  white-space: nowrap;
}

.back-link:hover {
  text-decoration: underline;
}

.page-title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text);
}

/* ─── Achievement Grid ──────────────────────────────────── */
.achievement-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1.25rem;
}

/* ─── Achievement Card ──────────────────────────────────── */
.achievement-card {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem 1rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.5rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.achievement-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
}

.achievement-card__icon {
  font-size: 2.5rem;
  line-height: 1;
}

.achievement-card__name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text);
}

.achievement-card__description {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.achievement-card__date {
  font-size: 0.75rem;
  color: var(--primary);
  font-weight: 500;
  margin-top: 0.25rem;
}

/* Unlocked state */
.achievement-card.unlocked {
  border-color: var(--primary);
  background: linear-gradient(135deg, #fff 0%, #f0efff 100%);
}

.achievement-card.unlocked .achievement-card__icon {
  animation: none;
}

/* Locked state */
.achievement-card.locked {
  background: var(--locked-bg);
  border-color: var(--border);
  opacity: 0.75;
}

.achievement-card.locked .achievement-card__icon {
  filter: grayscale(1);
  opacity: 0.5;
}

.achievement-card.locked .achievement-card__name {
  color: var(--locked-text);
}

.lock-icon {
  font-size: 0.85rem;
  margin-top: 0.125rem;
}

/* Celebration animation for newly unlocked */
@keyframes celebrate {
  0%   { transform: scale(1); }
  30%  { transform: scale(1.12); }
  60%  { transform: scale(0.96); }
  100% { transform: scale(1); }
}

.achievement-card.just-unlocked {
  animation: celebrate 0.5s ease forwards;
}

/* ─── Skeleton Loading ──────────────────────────────────── */
.skeleton-card {
  height: 180px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 2px solid var(--border);
  position: relative;
  overflow: hidden;
}

.skeleton-card::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    90deg,
    transparent 0%,
    rgba(255, 255, 255, 0.6) 50%,
    transparent 100%
  );
  animation: shimmer 1.4s infinite;
}

@keyframes shimmer {
  0%   { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* ─── Error State ───────────────────────────────────────── */
.error-state {
  text-align: center;
  padding: 3rem 1rem;
}

.error-state__message {
  color: var(--text-muted);
  margin-bottom: 1rem;
}

/* ─── Button ────────────────────────────────────────────── */
.btn {
  display: inline-block;
  padding: 0.6rem 1.4rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  text-decoration: none;
  transition: background 0.15s;
}

.btn--primary {
  background: var(--primary);
  color: #fff;
}

.btn--primary:hover {
  background: var(--primary-dark);
}

/* ─── Toast Notifications ───────────────────────────────── */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  z-index: 1000;
  pointer-events: none;
}

.toast {
  background: var(--text);
  color: #fff;
  border-radius: var(--radius-sm);
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
  opacity: 0;
  transform: translateY(20px);
  animation: toast-in 0.3s ease forwards, toast-out 0.3s ease 3.5s forwards;
  pointer-events: auto;
  max-width: 320px;
}

.toast__icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.toast__text strong {
  display: block;
  font-size: 0.85rem;
  font-weight: 700;
}

.toast__text span {
  font-size: 0.78rem;
  opacity: 0.8;
}

@keyframes toast-in {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes toast-out {
  to {
    opacity: 0;
    transform: translateY(20px);
  }
}

/* ─── Responsive ────────────────────────────────────────── */
@media (max-width: 480px) {
  body {
    padding: 1rem;
  }

  .achievement-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-title {
    font-size: 1.4rem;
  }
}