:root {
  color-scheme: light dark;
  --bg: #f5f8fa;
  --card: #ffffff;
  --text: #0f1419;
  --muted: #536471;
  --border: #e5e9ec;
  --accent: #1d9bf0;
  --accent-hover: #1a8cd8;
  --primary: var(--accent);
  --primary-hover: var(--accent-hover);
  --danger: #d63e66;
  --footer-bg: #eef3f7;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1419;
    --card: #17212b;
    --text: #e6edf3;
    --muted: #9fb0c0;
    --border: #2a3a48;
    --accent: #4fb3ff;
    --accent-hover: #78c4ff;
    --danger: #ff7a9a;
    --footer-bg: #111a22;
  }
}

:root[data-theme='light'] {
  color-scheme: light;
  --bg: #f5f8fa;
  --card: #ffffff;
  --text: #0f1419;
  --muted: #536471;
  --border: #e5e9ec;
  --accent: #1d9bf0;
  --accent-hover: #1a8cd8;
  --danger: #d63e66;
  --footer-bg: #eef3f7;
}

:root[data-theme='dark'] {
  color-scheme: dark;
  --bg: #0f1419;
  --card: #17212b;
  --text: #e6edf3;
  --muted: #9fb0c0;
  --border: #2a3a48;
  --accent: #4fb3ff;
  --accent-hover: #78c4ff;
  --danger: #ff7a9a;
  --footer-bg: #111a22;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  line-height: 1.5;
}

a {
  color: var(--primary);
}

.container {
  max-width: 600px;
  margin: 0 auto;
  padding: 0 16px;
}

.page-container {
  padding-top: 16px;
  padding-bottom: 24px;
}

.nav {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.nav-inner {
  min-height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  color: var(--text);
  font-weight: 800;
  text-decoration: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.nav-links a {
  text-decoration: none;
  color: var(--text);
}

.nav-links a:hover {
  color: var(--primary);
}

.inline-form {
  margin: 0;
}

.link-btn {
  border: 0;
  background: transparent;
  color: var(--primary);
  cursor: pointer;
  padding: 0;
}

.theme-toggle {
  color: var(--text);
  text-decoration: none;
}

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

.notif-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.notif-badge {
  display: inline-flex;
  min-width: 20px;
  height: 20px;
  align-items: center;
  justify-content: center;
  padding: 0 6px;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 700;
  color: #fff;
  background: var(--primary);
}

.auth-container {
  min-height: calc(100vh - 72px);
  display: grid;
  place-items: center;
}

.auth-card,
.panel,
.compose-box,
.tweet-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.auth-card,
.panel,
.compose-box {
  padding: 16px;
  margin-bottom: 16px;
}

.auth-form {
  display: grid;
  gap: 10px;
}

.auth-form input,
.search-form input,
.tweet-textarea {
  width: 100%;
  padding: 10px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  border-radius: 8px;
  font: inherit;
}

.media-label {
  margin-top: 10px;
  display: inline-block;
  color: var(--muted);
  font-size: 0.95rem;
}

.media-input {
  margin-top: 6px;
  width: 100%;
  color: var(--text);
}

.tweet-textarea {
  min-height: 96px;
  resize: vertical;
}

.btn-primary {
  border: 0;
  background: var(--primary);
  color: #fff;
  border-radius: 999px;
  font-weight: 700;
  cursor: pointer;
  padding: 8px 16px;
}

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

.btn-secondary {
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  border-radius: 999px;
  font-weight: 600;
  cursor: pointer;
  padding: 8px 14px;
}

.btn-secondary:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.compose-footer {
  margin-top: 10px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.char-counter {
  font-size: 0.9rem;
  color: var(--muted);
}

.char-counter.danger {
  color: var(--danger);
  font-weight: 700;
}

.form-error {
  background: #ffe4ec;
  color: #9f1239;
  border: 1px solid #fecdd9;
  border-radius: 8px;
  padding: 8px 10px;
}

.tweet-card {
  padding: 14px;
  margin-bottom: 12px;
}

.tweet-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
}

.tweet-author {
  color: var(--text);
  text-decoration: none;
}

.tweet-author:hover {
  text-decoration: underline;
}

.tweet-username,
.tweet-time,
.muted {
  color: var(--muted);
}

.tweet-content {
  margin: 10px 0 12px;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.tweet-image {
  width: 100%;
  max-height: 420px;
  object-fit: cover;
  border: 1px solid var(--border);
  border-radius: 12px;
  margin: 0 0 12px;
}

.tweet-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.like-btn,
.delete-btn {
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  border-radius: 999px;
  cursor: pointer;
  font: inherit;
  padding: 4px 10px;
}

.like-btn:hover,
.delete-btn:hover {
  border-color: #c8d0d6;
}

.like-btn.liked {
  color: var(--danger);
  border-color: var(--danger);
  background: var(--card);
}

.delete-btn {
  color: #a61b1b;
}

.reply-link,
.reply-count-link {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
}

.reply-link:hover,
.reply-count-link:hover {
  color: var(--primary);
  text-decoration: underline;
}

.reply-card {
  border-top: 1px solid var(--border);
  padding: 12px 0;
}

.reply-card:first-child {
  border-top: 0;
  padding-top: 0;
}

.profile-header h1,
.profile-header p {
  margin: 0 0 8px;
}

.profile-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.profile-counts {
  margin-top: 8px;
}

.notifications-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
}

.notifications-header h1 {
  margin: 0;
}

.notification-item {
  border-top: 1px solid var(--border);
  padding: 14px 0;
}

.notification-item:first-of-type {
  border-top: 0;
  padding-top: 4px;
}

.notification-item.unread {
  background: var(--card);
  border: 1px solid var(--primary);
  border-radius: 10px;
  padding: 12px;
}

.notification-item p {
  margin: 0 0 8px;
}

.notification-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.search-form {
  display: grid;
  gap: 10px;
}

.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;
}

.site-footer {
  margin-top: 24px;
  border-top: 1px solid var(--border);
  background: var(--footer-bg);
}

.site-footer p {
  margin: 0;
  padding: 14px 0 18px;
  color: var(--muted);
  font-size: 0.95rem;
}