/* ==========================================================================
   Base Reset & Variables
   ========================================================================== */

:root {
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-primary: #3b82f6;
  --color-primary-hover: #2563eb;
  --color-success: #22c55e;
  --color-error: #ef4444;
  --color-border: #e2e8f0;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 4px 6px rgba(0, 0, 0, 0.1);
  --transition: 150ms ease;
}

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

body {
  margin: 0;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* ==========================================================================
   App Layout
   ========================================================================== */

.app {
  max-width: 640px;
  margin: 0 auto;
  padding: 24px 16px;
}

.app__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.app__title {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0;
}

.app__logo {
  color: inherit;
  text-decoration: none;
}

.app__logo:hover {
  color: var(--color-primary);
}

.app__nav {
  display: flex;
  gap: 16px;
}

.app__link {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  text-decoration: none;
}

.app__link:hover {
  color: var(--color-primary);
}

.app__content {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
}

/* ==========================================================================
   Flash Messages
   ========================================================================== */

.flash {
  padding: 12px 16px;
  border-radius: var(--radius);
  margin-bottom: 16px;
  font-size: 0.875rem;
}

.flash--notice {
  background: #dcfce7;
  color: #166534;
}

.flash--alert {
  background: #fee2e2;
  color: #991b1b;
}

/* ==========================================================================
   Dropzone
   ========================================================================== */

.dropzone {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius);
  padding: 48px 24px;
  text-align: center;
  cursor: pointer;
  transition: border-color var(--transition), background-color var(--transition);
  position: relative;
}

.dropzone:hover,
.dropzone--active {
  border-color: var(--color-primary);
  background: #eff6ff;
}

.dropzone__content {
  pointer-events: none;
}

.dropzone__icon {
  width: 48px;
  height: 48px;
  color: var(--color-text-muted);
  margin-bottom: 16px;
}

.dropzone--active .dropzone__icon {
  color: var(--color-primary);
}

.dropzone__text {
  font-size: 1rem;
  font-weight: 500;
  margin: 0 0 4px;
}

.dropzone__hint {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: 0;
}

.dropzone__input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

/* ==========================================================================
   File List
   ========================================================================== */

.file-list {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
}

.file-item {
  display: grid;
  grid-template-columns: 1fr auto;
  grid-template-rows: auto auto;
  gap: 4px 12px;
  padding: 12px;
  background: var(--color-bg);
  border-radius: var(--radius);
  margin-bottom: 8px;
}

.file-item:last-child {
  margin-bottom: 0;
}

.file-item__name {
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-item__size {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  text-align: right;
}

.file-item__progress {
  grid-column: 1 / -1;
  height: 4px;
  background: var(--color-border);
  border-radius: 2px;
  overflow: hidden;
}

.file-item__bar {
  height: 100%;
  background: var(--color-primary);
  transition: width var(--transition);
}

.file-item--complete .file-item__bar {
  background: var(--color-success);
}

.file-item--error .file-item__bar {
  background: var(--color-error);
}

.file-item__status {
  grid-column: 1 / -1;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  text-align: right;
}

.file-item--complete .file-item__status {
  color: var(--color-success);
}

.file-item--error .file-item__status {
  color: var(--color-error);
}

/* ==========================================================================
   Upload Form
   ========================================================================== */

.upload-form__actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 24px;
}

.upload-form__title {
  width: 100%;
  padding: 12px 16px;
  font-size: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: border-color var(--transition);
}

.upload-form__title:focus {
  outline: none;
  border-color: var(--color-primary);
}

.upload-form__submit {
  width: 100%;
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 500;
  color: #fff;
  background: var(--color-primary);
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background-color var(--transition);
}

.upload-form__submit:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

.upload-form__submit:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* ==========================================================================
   Track List
   ========================================================================== */

.track-list__header {
  margin-bottom: 24px;
}

.track-list__title {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0;
}

.track-list__empty {
  text-align: center;
  color: var(--color-text-muted);
  padding: 48px 0;
  margin: 0;
}

.track-card {
  padding: 16px;
  background: var(--color-bg);
  border-radius: var(--radius);
  margin-bottom: 12px;
}

.track-card:last-child {
  margin-bottom: 0;
}

.track-card__title {
  font-size: 1rem;
  font-weight: 500;
  margin: 0 0 4px;
}

.track-card__count {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: 0 0 12px;
}

.track-card__actions {
  display: flex;
  gap: 12px;
  align-items: center;
}

.track-card__link {
  font-size: 0.875rem;
  color: var(--color-primary);
  text-decoration: none;
}

.track-card__link:hover {
  text-decoration: underline;
}

.track-card__delete {
  font-size: 0.875rem;
  color: var(--color-error);
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
}

.track-card__delete:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Track Detail
   ========================================================================== */

.track-detail__header {
  margin-bottom: 24px;
}

.track-detail__title {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 4px;
}

.track-detail__meta {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: 0;
}

.track-detail__files {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
}

.track-detail__file {
  padding: 16px;
  background: var(--color-bg);
  border-radius: var(--radius);
  margin-bottom: 12px;
}

.track-detail__file:last-child {
  margin-bottom: 0;
}

.track-detail__file-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.track-detail__filename {
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.track-detail__filesize {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  flex-shrink: 0;
  margin-left: 12px;
}

.track-detail__audio {
  width: 100%;
  height: 40px;
}

.track-detail__download {
  display: inline-block;
  font-size: 0.875rem;
  color: var(--color-primary);
  text-decoration: none;
}

.track-detail__download:hover {
  text-decoration: underline;
}

.track-detail__actions {
  display: flex;
  gap: 16px;
  align-items: center;
  padding-top: 16px;
  border-top: 1px solid var(--color-border);
}

.track-detail__back {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  text-decoration: none;
}

.track-detail__back:hover {
  color: var(--color-primary);
}

.track-detail__delete {
  font-size: 0.875rem;
  color: var(--color-error);
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
}

.track-detail__delete:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Responsive
   ========================================================================== */

@media (min-width: 480px) {
  .app {
    padding: 48px 24px;
  }

  .app__content {
    padding: 32px;
  }
}