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

/* ── Variables ───────────────────────────────────────────────────────────── */
:root {
  --bg-base:        #ffffff;
  --bg-additive:    #f2f2f2;
  --bg-hover:       #e5e5e5;
  --text-primary:   #0f0f0f;
  --text-secondary: #606060;

  --space-xs:  4px;
  --space-sm:  8px;
  --space-md:  12px;
  --space-lg:  16px;
  --space-xl:  24px;
  --space-2xl: 40px;

  --radius-sm:   8px;
  --radius-lg:   12px;
  --radius-pill: 9999px;

  --font-sans:   "Roboto", "Apple SD Gothic Neo", "Malgun Gothic", "맑은 고딕", sans-serif;
  --fs-meta:     12px;
  --fs-body:     14px;
  --fs-title:    16px;
  --fs-section:  20px;
  --fw-regular:  400;
  --fw-medium:   500;
  --fw-semibold: 600;
  --fw-bold:     700;

  --header-h: 56px;
  --card-min-width: 400px;
}

/* ── Base ────────────────────────────────────────────────────────────────── */
body {
  font-family: var(--font-sans);
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ── Auth screen ─────────────────────────────────────────────────────────── */
.auth-center {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 48px 24px;
}

.auth-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}

.auth-logo-text {
  font-size: var(--fs-section);
  font-weight: var(--fw-bold);
  color: var(--text-primary);
}

.auth-desc {
  font-size: var(--fs-body);
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 32px;
}

.login-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: var(--fw-medium);
  color: var(--text-primary);
  text-decoration: none;
  background: var(--bg-additive);
  padding: 10px 20px;
  border-radius: var(--radius-pill);
  transition: background 0.15s;
}
.login-btn:hover { background: var(--bg-hover); }

/* ── App header ──────────────────────────────────────────────────────────── */
.app-header {
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-xl);
  position: sticky;
  top: 0;
  background: var(--bg-base);
  border-bottom: 0;
  z-index: 50;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--fs-title);
  font-weight: var(--fw-bold);
  color: var(--text-primary);
  white-space: nowrap;
}

#sync-status {
  font-size: var(--fs-meta);
  color: var(--text-secondary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header-actions button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: var(--fw-medium);
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  border: none;
  cursor: pointer;
  transition: background 0.15s;
}

.header-actions button svg {
  width: 18px;
  height: 18px;
  flex: 0 0 auto;
}

#copyAll   { background: var(--bg-additive); color: var(--text-primary); }
#copyAll:hover { background: var(--bg-hover); }

#logoutBtn { background: transparent; color: var(--text-secondary); }
#logoutBtn:hover { background: var(--bg-additive); }

/* ── Main sections ──────────────────────────────────────────────────────── */
.app-main {
  width: 100%;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.library-section {
  padding-top: var(--space-lg);
}

.section-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}

.section-heading h2 {
  margin-top: var(--space-xs);
  font-size: var(--fs-section);
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.section-heading p {
  margin-top: var(--space-sm);
  color: var(--text-secondary);
  font-size: var(--fs-body);
}

.eyebrow {
  color: var(--text-secondary);
  font-size: 11px;
  font-weight: var(--fw-bold);
  letter-spacing: 0.12em;
}

.library-controls {
  display: flex;
  flex-wrap: nowrap;
  gap: var(--space-md);
  margin: calc(var(--space-md) * -1) 0 var(--space-xl);
  padding-bottom: var(--space-xs);
  overflow-x: auto;
  scrollbar-width: none;
}

.library-controls::-webkit-scrollbar { display: none; }

.filter-control {
  position: relative;
  flex: 0 0 auto;
}

.filter-control::after {
  width: 6px;
  height: 6px;
  position: absolute;
  top: 50%;
  right: 14px;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  content: "";
  pointer-events: none;
  transform: translateY(-65%) rotate(45deg);
}

.filter-control select,
.reset-filters {
  min-height: 36px;
  border: 0;
  border-radius: var(--radius-sm);
  background: var(--bg-additive);
  white-space: nowrap;
  cursor: pointer;
}

.filter-control select {
  padding: 0 36px 0 12px;
  color: var(--text-primary);
  appearance: none;
  -webkit-appearance: none;
  font: var(--fw-medium) var(--fs-body) var(--font-sans);
  transition: background-color 0.15s ease;
}

.filter-control select:hover,
.reset-filters:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.reset-filters {
  padding: 0 12px;
  color: var(--text-secondary);
  font-size: var(--fs-body);
  font-family: var(--font-sans);
  font-weight: var(--fw-regular);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ── Load more (infinite scroll) ────────────────────────────────────────── */
.load-more {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-xl) var(--space-lg);
  color: var(--text-secondary);
  font-size: var(--fs-meta);
}

.load-more:empty { padding: 0; }

.load-more-spinner {
  width: 16px;
  height: 16px;
  border: 2px solid var(--bg-hover);
  border-top-color: var(--text-secondary);
  border-radius: 50%;
  animation: load-more-spin 0.7s linear infinite;
}

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

/* ── Grid ────────────────────────────────────────────────────────────────── */
.grid {
  padding: 0;
}

.grid p {
  font-size: var(--fs-body);
  color: var(--text-secondary);
  text-align: center;
  padding: 80px 24px;
}

.category-grid {
  position: relative;
  width: 100%;
  margin: 0 auto;
}

/* ── Skeleton ────────────────────────────────────────────────────────────── */
.skeleton-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(var(--card-min-width), 1fr));
  gap: var(--space-lg);
}

.skeleton-card {
  aspect-ratio: 9 / 16;
  border-radius: var(--radius-lg);
  background: linear-gradient(90deg, var(--bg-additive) 25%, var(--bg-hover) 50%, var(--bg-additive) 75%);
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.2s ease-in-out infinite;
}

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

/* ── Cards ───────────────────────────────────────────────────────────────── */
.card {
  position: relative;
  cursor: grab;
  animation: card-in 0.3s ease both;
  min-width: 0;
}

.card:active { cursor: grabbing; }
.card[draggable="false"] { cursor: default; }

@keyframes card-in {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

.card:nth-child(1)  { animation-delay: .03s; }
.card:nth-child(2)  { animation-delay: .06s; }
.card:nth-child(3)  { animation-delay: .09s; }
.card:nth-child(4)  { animation-delay: .12s; }
.card:nth-child(5)  { animation-delay: .15s; }
.card:nth-child(6)  { animation-delay: .18s; }
.card:nth-child(7)  { animation-delay: .21s; }
.card:nth-child(8)  { animation-delay: .24s; }
.card:nth-child(9)  { animation-delay: .27s; }
.card:nth-child(10) { animation-delay: .30s; }
.card:nth-child(11) { animation-delay: .33s; }
.card:nth-child(12) { animation-delay: .36s; }
.card:nth-child(13) { animation-delay: .39s; }
.card:nth-child(14) { animation-delay: .42s; }
.card:nth-child(15) { animation-delay: .45s; }
.card:nth-child(16) { animation-delay: .48s; }
.card:nth-child(17) { animation-delay: .51s; }
.card:nth-child(18) { animation-delay: .54s; }
.card:nth-child(19) { animation-delay: .57s; }
.card:nth-child(20) { animation-delay: .60s; }

/* ── Thumbnails ──────────────────────────────────────────────────────────── */
.thumb-container {
  display: block;
  width: 100%;
  position: relative;
  aspect-ratio: 16 / 9;
  background: var(--bg-additive);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  border-radius: var(--radius-lg);  /* 12px - docs/design.md section 4.3 */
}

.duration-badge {
  padding: 3px 5px;
  position: absolute;
  right: 6px;
  bottom: 6px;
  border-radius: 4px;
  background: rgba(0,0,0,0.82);
  color: #fff;
  font-size: 11px;
  font-weight: var(--fw-medium);
}

.thumb-container.short-container {
  aspect-ratio: 9 / 16;
}

/* ── Delete button ──────────────────────────────────────────────────────── */
.delete-button {
  position: absolute;
  top: 6px;
  right: 6px;
  width: 28px;
  height: 28px;
  background: rgba(0,0,0,0.55);
  border: none;
  border-radius: var(--radius-sm);
  color: #fff;
  font-size: 20px;
  line-height: 28px;
  text-align: center;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s, background 0.15s;
}

.card:hover .delete-button { opacity: 1; }
.delete-button:hover { background: rgba(0,0,0,0.75); }

/* ── Drag ─────────────────────────────────────────────────────────────────── */
.card.dragging { opacity: 0.25; }

.category-grid.drag-over {
  outline: 2px dashed var(--text-secondary);
  outline-offset: 8px;
}

/* ── Mobile ──────────────────────────────────────────────────────────────── */
@media (max-width: 768px) {
  .app-header { padding: 0 var(--space-md); }
  .app-main { padding: 0 var(--space-sm); }
  #sync-status { display: none; }
  #copyAll span,
  #logoutBtn { display: none; }
  .header-actions button { padding: 8px; }

  .section-heading {
    align-items: flex-start;
    margin-bottom: var(--space-lg);
  }

  .library-heading { align-items: flex-end; }
  .skeleton-grid { grid-template-columns: repeat(2, 1fr); gap: var(--space-sm); }
}

/* YouTube-inspired refinement — docs/design.md */
.header-actions button:focus-visible,
.login-btn:focus-visible,
.filter-control select:focus-visible,
.reset-filters:focus-visible,
.card a:focus-visible {
  outline: 2px solid #065fd4;
  outline-offset: 2px;
}

.sort-control { color: var(--text-primary); }

.sort-control select {
  min-width: 142px;
  padding-left: 38px;
  font-weight: var(--fw-semibold);
}

.sort-control::before {
  width: 16px;
  height: 16px;
  position: absolute;
  top: 50%;
  left: 13px;
  z-index: 1;
  background: currentColor;
  content: "";
  pointer-events: none;
  transform: translateY(-50%);
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M3 6h13M3 12h10M3 18h7M19 4v16m0 0-3-3m3 3 3-3' fill='none' stroke='black' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center / contain no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M3 6h13M3 12h10M3 18h7M19 4v16m0 0-3-3m3 3 3-3' fill='none' stroke='black' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center / contain no-repeat;
}

.sort-control select:hover,
.sort-control select:focus-visible {
  background-color: var(--bg-hover);
  color: var(--text-primary);
}

.sort-control select option {
  background: var(--bg-base);
  color: var(--text-primary);
}