/* Basic reset */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* Theme variables (light mode default) */
:root {
  --bg: #eaeaea;
  --card: #fff;
  --text: #000;
  --secondary-text: #555;
  --border: #dbdbdb;
  --input-bg: #fafafa;
  --shadow: rgba(0, 0, 0, 0.06);
  --fast: 0.15s;
  --medium: 0.25s;
  --ease: ease;
}

/* Dark mode overrides */
body.dark-mode {
  --bg: #0f0f0f;
  --card: #1a1a1a;
  --text: #f5f5f5;
  --secondary-text: #a8a8a8;
  --border: #262626;
  --input-bg: #222;
  --shadow: rgba(0, 0, 0, 0.6);
}

/* Page layout */
body {
  font-family: 'Source Sans 3', sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
}

/* App container (mobile-like layout) */
.app {
  width: 100%;
  max-width: 420px;
  background: var(--card);
}

/* Top nav */
nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  background: var(--card);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 2px 8px var(--shadow);
}

.nav-logo-text {
  font-family: 'Dancing Script', cursive;
  font-size: 2rem;
}

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

.nav-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border);
}

/* Dark mode switch */
.theme-switch {
  position: relative;
  width: 42px;
  height: 22px;
}

.theme-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  inset: 0;
  background: #e4e4e4;
  border-radius: 999px;
  cursor: pointer;
  transition: 0.3s ease;
}

body.dark-mode .slider {
  background: #444;
}

.slider::before {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  left: 3px;
  top: 50%;
  transform: translateY(-50%);
  background: white;
  border-radius: 50%;
  transition: 0.3s ease;
}

.theme-switch input:checked + .slider {
  background: #3897f0;
}

.theme-switch input:checked + .slider::before {
  transform: translate(20px, -50%);
}

/* Stories row */
.stories {
  display: flex;
  gap: 12px;
  padding: 12px;
  overflow-x: auto;
  border-bottom: 1px solid var(--border);
  scroll-snap-type: x mandatory;
}

/* Story item */
.story {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  flex: 0 0 auto;
  scroll-snap-align: start;
}

/* Story avatar ring */
.story-ring {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  padding: 2px;
  background: linear-gradient(45deg, #f09433, #e6683c, #dc2743, #cc2366, #bc1888);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform var(--medium) var(--ease);
}

.story-ring img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--card);
}

/* Seen story state */
.story-ring.seen {
  background: #ccc;
}

.story-ring:hover {
  transform: scale(1.08);
}

/* Feed layout */
main {
  width: 100%;
  padding-bottom: 80px;
}

/* Individual post card */
.post {
  margin-bottom: 12px;
  background: var(--card);
  border-radius: 8px;
  box-shadow: 0 2px 6px var(--shadow);
}

/* Post header */
.post-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
}

.avatar {
  width: 56px;
  height: 56px;
  border-radius: 50%;
}

/* Location text under username */
.location {
  font-size: 0.82rem;
  color: var(--secondary-text);
}

/* Post image */
.post-image {
  width: 100%;
  display: block;
  margin-bottom: 8px;
  transition: transform var(--medium) var(--ease);
}

.post-image:active {
  transform: scale(0.98);
}

/* Action icons row */
.post-actions {
  display: flex;
  padding: 8px 12px;
}

.left-icons {
  display: flex;
  gap: 16px;
}

.icon {
  width: 30px;
  height: 30px;
  cursor: pointer;
  transition: transform var(--fast) var(--ease), opacity var(--fast) var(--ease);
}

.icon:hover {
  transform: scale(1.15);
  opacity: 0.7;
}

/* Dark mode icon adjustment */
body.dark-mode .icon {
  filter: brightness(0) invert(1);
}

/* Like state */
.heart-icon.liked {
  filter: invert(32%) sepia(98%) saturate(7492%) hue-rotate(356deg) !important;
}

/* Heart animation */
@keyframes heartPop {
  0% { transform: scale(1); }
  25% { transform: scale(1.25); }
  50% { transform: scale(0.92); }
  100% { transform: scale(1); }
}

.heart-pop {
  animation: heartPop var(--medium) var(--ease);
}

/* Likes + caption */
.likes {
  padding: 0 12px 4px;
}

.caption {
  padding: 0 12px 8px;
}

/* Username styling */
.username a,
.username-link {
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  transition: opacity 0.15s ease, color 0.15s ease;
}

.username a:hover,
.username-link:hover {
  opacity: 0.8;
  color: #3897f0;
  cursor: pointer;
}

/* Comment box */
.comment-box {
  display: flex;
  gap: 8px;
  padding: 10px 12px 12px;
  border-top: 1px solid var(--border);
}

.comment-box input {
  flex: 1;
  border: 1px solid var(--border);
  background: var(--input-bg);
  border-radius: 18px;
  padding: 10px 12px;
  font-size: 0.9rem;
  color: var(--text);
  outline: none;
}

.comment-box button {
  background: none;
  border: none;
  font-weight: 700;
  cursor: pointer;
  color: #b3d7ff;
  pointer-events: none;
}

/* Active comment button */
.comment-box button.active {
  color: #3897f0;
  pointer-events: auto;
}

/* Bottom navigation */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  max-width: 420px;
  display: flex;
  justify-content: space-around;
  align-items: center;
  height: 52px;
  background: var(--card);
  border-top: 1px solid var(--border);
}

.nav-btn {
  background: none;
  border: none;
  width: 36px;
  height: 36px;
  opacity: 0.7;
  cursor: pointer;
  transition: transform 0.15s ease, opacity 0.15s ease;
}

.nav-btn.active {
  opacity: 1;
  transform: translateY(-1px);
}

.nav-btn:active {
  transform: scale(0.96);
}

.nav-icon {
  width: 24px;
  height: 24px;
}

.nav-btn:hover {
  transform: translateY(-2px);
  opacity: 1;
}

.nav-btn:hover .nav-icon {
  filter: brightness(1.1);
}

body.dark-mode .nav-icon {
  filter: brightness(0) invert(1);
  transition: transform 0.18s ease, opacity 0.18s ease, filter 0.18s ease;
}

body.dark-mode .nav-btn:hover .nav-icon,
body.dark-mode .nav-btn.active .nav-icon,
body.dark-mode .nav-btn:active .nav-icon {
  filter: brightness(0) invert(1);
}