:root {
  --font-size-base: 18px;
  --font-size-lg: 20px;
  --font-size-xl: 24px;
  --line-height: 1.5;
  --color-text: #1a1a1a;
  --color-bg: #f5f5f5;
  --color-card-bg: #ffffff;
  --color-border: #d1d5db;
  --color-secondary: #374151;
  --color-error: #991b1b;
  --tap-target-min: 44px;
  --grid-gap: 16px;
  --card-radius: 8px;
  --card-padding: 12px 16px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", sans-serif;
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  background: var(--color-bg);
}

header {
  text-align: center;
  padding: 24px var(--grid-gap) 8px;
}

header h1 {
  font-size: var(--font-size-xl);
}

.photo-count {
  font-size: var(--font-size-base);
  color: var(--color-secondary);
  margin-top: 4px;
}

.loading {
  text-align: center;
  padding: 48px var(--grid-gap);
  font-size: var(--font-size-lg);
  color: var(--color-secondary);
}

.error-message {
  text-align: center;
  padding: 48px var(--grid-gap);
  font-size: var(--font-size-lg);
  color: var(--color-error);
}

.gallery-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--grid-gap);
  padding: var(--grid-gap);
  max-width: 1200px;
  margin: 0 auto;
}

@media (min-width: 600px) {
  .gallery-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .gallery-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.photo-card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--card-radius);
  overflow: hidden;
  cursor: pointer;
}

.photo-card:focus {
  outline: 3px solid #1d4ed8;
  outline-offset: 2px;
}

.photo-card img {
  width: 100%;
  height: auto;
  display: block;
}

.card-body {
  padding: var(--card-padding);
}

.species-name {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: 4px;
}

.card-meta {
  font-size: var(--font-size-base);
  color: var(--color-secondary);
  line-height: var(--line-height);
}

.card-meta span {
  display: block;
}

/* --- Lightbox --- */

body.lightbox-open {
  overflow: hidden;
}

.lightbox-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.85);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--grid-gap);
}

.lightbox-overlay[hidden] {
  display: none;
}

.lightbox-content {
  position: relative;
  background: var(--color-card-bg);
  border-radius: var(--card-radius);
  max-width: 900px;
  max-height: 90vh;
  width: 100%;
  overflow: auto;
}

.lightbox-close {
  position: absolute;
  top: 8px;
  right: 8px;
  min-width: var(--tap-target-min);
  min-height: var(--tap-target-min);
  font-size: var(--font-size-xl);
  font-family: inherit;
  background: rgba(0, 0, 0, 0.6);
  color: #ffffff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.lightbox-close:focus {
  outline: 3px solid #ffffff;
  outline-offset: 2px;
}

.lightbox-image img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: var(--card-radius) var(--card-radius) 0 0;
}

.lightbox-info {
  padding: 16px 20px 20px;
}

/* --- Species Filter Chips --- */

.species-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 12px var(--grid-gap);
  max-width: 1200px;
  margin: 0 auto;
  justify-content: center;
}

.species-chip {
  font-family: inherit;
  font-size: var(--font-size-base);
  font-weight: 700;
  padding: 10px 20px;
  min-height: var(--tap-target-min);
  border: 2px solid var(--color-border);
  border-radius: 999px;
  background: var(--color-card-bg);
  color: var(--color-text);
  cursor: pointer;
}

.species-chip.active {
  background: #1d4ed8;
  color: #ffffff;
  border-color: #1d4ed8;
}

.species-chip:focus {
  outline: 3px solid #1d4ed8;
  outline-offset: 2px;
}

/* --- Load More --- */

.load-more-container {
  text-align: center;
  padding: 16px var(--grid-gap) 32px;
  max-width: 1200px;
  margin: 0 auto;
}

.load-more-btn {
  font-family: inherit;
  font-size: var(--font-size-lg);
  font-weight: 700;
  padding: 14px 48px;
  min-height: var(--tap-target-min);
  border: 2px solid #1d4ed8;
  border-radius: var(--card-radius);
  background: var(--color-card-bg);
  color: #1d4ed8;
  cursor: pointer;
}

.load-more-btn:focus {
  outline: 3px solid #1d4ed8;
  outline-offset: 2px;
}

/* --- Navigation --- */

nav {
  margin-top: 8px;
}

.nav-link {
  display: inline-block;
  font-size: var(--font-size-lg);
  padding: 10px 20px;
  min-height: var(--tap-target-min);
  color: #1d4ed8;
  text-decoration: underline;
}

/* --- Upload Form --- */

.upload-form {
  max-width: 600px;
  margin: 0 auto;
  padding: var(--grid-gap);
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: 8px;
}

.form-group input[type="text"],
.form-group input[type="date"] {
  width: 100%;
  font-size: var(--font-size-base);
  padding: 12px 16px;
  border: 2px solid var(--color-border);
  border-radius: var(--card-radius);
  min-height: var(--tap-target-min);
}

.form-group input[type="text"]:focus,
.form-group input[type="date"]:focus {
  outline: 3px solid #1d4ed8;
  outline-offset: 2px;
}

.file-label {
  display: inline-block;
  font-size: var(--font-size-lg);
  font-weight: 700;
  padding: 14px 28px;
  background: #1d4ed8;
  color: #ffffff;
  border-radius: var(--card-radius);
  cursor: pointer;
  min-height: var(--tap-target-min);
}

.file-input {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
}

.file-name {
  display: block;
  margin-top: 8px;
  font-size: var(--font-size-base);
  color: var(--color-secondary);
}

.preview-container {
  margin-bottom: 20px;
}

.preview-container img {
  max-width: 100%;
  height: auto;
  border-radius: var(--card-radius);
  border: 1px solid var(--color-border);
}

.submit-btn {
  display: block;
  width: 100%;
  font-size: var(--font-size-xl);
  font-weight: 700;
  padding: 16px;
  background: #16a34a;
  color: #ffffff;
  border: none;
  border-radius: var(--card-radius);
  cursor: pointer;
  min-height: var(--tap-target-min);
}

.submit-btn:disabled {
  background: #9ca3af;
  cursor: not-allowed;
}

.upload-spinner {
  text-align: center;
  font-size: var(--font-size-lg);
  color: var(--color-secondary);
  padding: 16px;
}

.upload-success {
  text-align: center;
  font-size: var(--font-size-lg);
  color: #166534;
  font-weight: 700;
  padding: 16px;
}

.upload-error {
  text-align: center;
  font-size: var(--font-size-lg);
  color: var(--color-error);
  font-weight: 700;
  padding: 16px;
}