:root {
  --bg: #f4f6ff;
  --bg-glow: #d3d3ff;
  --surface: rgba(255, 255, 255, 0.96);
  --surface-strong: #ffffff;
  --text: #33447d;
  --muted: #6f7ab5;
  --line: rgba(0, 0, 128, 0.14);
  --ink: #000080;
  --teal: #00cec8;
  --teal-soft: rgba(0, 206, 200, 0.12);
  --lavender: #d3d3ff;
  --lavender-soft: rgba(211, 211, 255, 0.5);
  --navy-soft: rgba(0, 0, 128, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  font-family: "Segoe UI", Arial, sans-serif;
  margin: 0;
  background:
    radial-gradient(circle at top left, rgba(0, 206, 200, 0.18), transparent 24%),
    radial-gradient(circle at top right, rgba(211, 211, 255, 0.8), transparent 26%),
    linear-gradient(180deg, #ffffff 0%, var(--bg-glow) 42%, var(--bg) 100%);
  color: var(--text);
}

header {
  padding: 26px 20px 18px;
}

.header-bar {
  width: min(560px, calc(100% - 28px));
  margin: 0 auto;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
}

.brand-block {
  min-width: 0;
}

header h1 {
  margin: 0;
  font-size: clamp(30px, 8vw, 46px);
  letter-spacing: 0.02em;
  font-weight: 800;
  color: var(--ink);
  text-align: left;
}

header p {
  margin: 10px 0 0;
  max-width: 360px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
  text-align: left;
}

section {
  width: min(560px, calc(100% - 28px));
  margin: 0 auto;
}

section:last-of-type {
  padding-bottom: 36px;
}

#feed {
  display: block;
}

.feed-divider {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 10px 0 22px;
}

.feed-divider-line {
  flex: 1 1 auto;
  height: 1px;
  background: linear-gradient(
    90deg,
    rgba(0, 0, 128, 0),
    rgba(0, 0, 128, 0.18),
    rgba(0, 0, 128, 0)
  );
}

.feed-divider-body {
  flex: 0 0 auto;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 12px 16px;
  border-radius: 18px;
  border: 1px solid rgba(0, 206, 200, 0.22);
  background: rgba(255, 255, 255, 0.84);
  box-shadow: 0 10px 24px rgba(0, 0, 128, 0.05);
  text-align: center;
}

.feed-divider-body strong {
  color: var(--ink);
  font-size: 13px;
  letter-spacing: 0.02em;
}

.feed-divider-body span {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.4;
}

#saved-section {
  margin-bottom: 16px;
}

#saved-feed {
  margin-top: 2px;
}

#saved-feed[hidden] {
  display: none;
}

#saved-header-toggle {
  position: relative;
  flex: 0 0 auto;
  width: 46px;
  height: 46px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  border: 1px solid rgba(0, 0, 128, 0.12);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.84);
  color: var(--ink);
  cursor: pointer;
  box-shadow: 0 10px 24px rgba(0, 0, 128, 0.05);
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

#saved-header-toggle:hover {
  transform: translateY(-1px);
  border-color: rgba(0, 206, 200, 0.32);
  box-shadow: 0 16px 28px rgba(0, 0, 128, 0.08);
}

#saved-header-toggle[aria-expanded="true"] {
  background: rgba(255, 255, 255, 0.96);
  border-color: rgba(0, 206, 200, 0.34);
}

#saved-header-toggle.has-saved-items {
  border-color: rgba(0, 206, 200, 0.34);
}

#saved-header-count {
  position: absolute;
  top: -6px;
  right: -6px;
  min-width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0 6px;
  background: var(--ink);
  color: #ffffff;
  font-size: 11px;
  font-weight: 800;
}

.bookmark-icon {
  width: 14px;
  height: 18px;
  display: inline-block;
  fill: currentColor;
  flex: 0 0 auto;
}

#scroll-top-button {
  position: fixed;
  right: 18px;
  bottom: 22px;
  width: 52px;
  height: 52px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(0, 206, 200, 0.28);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.94);
  color: var(--ink);
  box-shadow: 0 16px 30px rgba(0, 0, 128, 0.14);
  cursor: pointer;
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: opacity 0.22s ease, transform 0.22s ease, border-color 0.22s ease, box-shadow 0.22s ease;
  z-index: 20;
}

#scroll-top-button span {
  font-size: 22px;
  font-weight: 800;
  line-height: 1;
}

#scroll-top-button.is-visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

#scroll-top-button:hover {
  border-color: rgba(0, 206, 200, 0.48);
  box-shadow: 0 20px 34px rgba(0, 0, 128, 0.18);
}

#filters {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding: 4px 0 18px;
  margin-bottom: 4px;
  scrollbar-width: none;
}

#filters::-webkit-scrollbar {
  display: none;
}

.filter-chip {
  flex: 0 0 auto;
  border: 1px solid rgba(0, 0, 128, 0.12);
  background: rgba(255, 255, 255, 0.88);
  color: var(--muted);
  border-radius: 999px;
  padding: 10px 14px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.filter-chip.is-active {
  background: var(--teal-soft);
  color: var(--ink);
  border-color: rgba(0, 206, 200, 0.45);
}

.card {
  display: block;
  position: relative;
  background: var(--surface);
  padding: 22px;
  margin-bottom: 18px;
  border-radius: 28px;
  border: 1px solid var(--line);
  box-shadow: 0 18px 40px rgba(0, 0, 128, 0.08);
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
  text-decoration: none;
  color: inherit;
  overflow: hidden;
}

.card.is-read {
  background: rgba(255, 255, 255, 0.82);
  border-color: rgba(0, 0, 128, 0.08);
  box-shadow: 0 14px 30px rgba(0, 0, 128, 0.04);
}

.card.is-read-pending {
  border-color: rgba(0, 206, 200, 0.45);
  box-shadow: 0 22px 40px rgba(0, 206, 200, 0.16);
}

.card.is-read-exit {
  animation: card-read-exit 820ms cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

.card.is-unread-exit {
  animation: card-unread-exit 680ms cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

.card.is-read h2,
.card.is-read h3,
.card.is-read p,
.card.is-read strong {
  opacity: 0.8;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 24px 46px rgba(0, 0, 128, 0.14);
  border-color: rgba(0, 206, 200, 0.38);
}

.card h2,
.card h3 {
  margin-top: 0;
  margin-bottom: 12px;
  line-height: 1.15;
  color: var(--ink);
}

.card h2 {
  font-size: 23px;
}

.card h3 {
  font-size: 23px;
}

.category {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--teal);
  margin-bottom: 12px;
  text-transform: uppercase;
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.why-it-matters {
  display: inline-block;
  background: var(--teal-soft);
  color: var(--ink);
  font-size: 13px;
  font-weight: 700;
  padding: 6px 12px;
  border-radius: 999px;
}

.new-badge {
  display: inline-block;
  background: var(--lavender-soft);
  color: var(--ink);
  font-size: 12px;
  font-weight: 800;
  padding: 6px 12px;
  border-radius: 999px;
}

.card p {
  line-height: 1.75;
  color: var(--text);
}

.card ul {
  padding-left: 20px;
  margin-top: 8px;
  color: var(--muted);
}

.key-points {
  margin: 18px 0 16px;
  padding: 14px 16px 12px;
  background: rgba(211, 211, 255, 0.22);
  border: 1px solid rgba(0, 0, 128, 0.12);
  border-radius: 18px;
}

.key-points strong {
  display: block;
  margin-bottom: 8px;
  color: var(--ink);
  font-size: 14px;
  letter-spacing: 0.02em;
}

.key-points ul {
  margin: 0;
  padding-left: 18px;
  color: #324177;
}

.key-points li {
  margin-bottom: 8px;
  line-height: 1.65;
}

.key-points li:last-child {
  margin-bottom: 0;
}

.card strong {
  color: var(--ink);
}

.card li::marker {
  color: var(--teal);
}

.card-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: 18px;
  padding-top: 8px;
}

.card-action {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.card-action-save {
  margin-left: auto;
}

.read-toggle {
  position: relative;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid rgba(0, 206, 200, 0.42);
  background: rgba(0, 206, 200, 0.12);
  color: var(--teal);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform 0.18s ease, background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.read-toggle:hover {
  transform: scale(1.05);
  background: rgba(0, 206, 200, 0.18);
  border-color: rgba(0, 206, 200, 0.56);
}

.read-toggle.is-read {
  background: var(--ink);
  color: #ffffff;
  border-color: rgba(0, 0, 128, 0.8);
}

.read-toggle-icon {
  font-size: 18px;
  font-weight: 800;
  line-height: 1;
}

.direction-cue {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  font-size: 22px;
  font-weight: 800;
  line-height: 1;
  pointer-events: none;
  opacity: 0;
}

.direction-cue-down {
  color: var(--teal);
  animation: direction-cue-down 620ms ease-out forwards;
}

.direction-cue-up {
  color: var(--ink);
  animation: direction-cue-up 600ms ease-out forwards;
}

.read-toggle-text {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.save-toggle {
  position: relative;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid rgba(0, 0, 128, 0.18);
  background: rgba(211, 211, 255, 0.32);
  color: var(--ink);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform 0.18s ease, background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.save-toggle:hover {
  transform: scale(1.05);
  background: rgba(211, 211, 255, 0.48);
  border-color: rgba(0, 0, 128, 0.28);
}

.save-toggle.is-saved {
  background: var(--ink);
  color: #ffffff;
  border-color: rgba(0, 0, 128, 0.8);
}

.save-toggle-icon {
  width: 12px;
  height: 16px;
}

.save-toggle-text {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.read-burst {
  position: absolute;
  left: 50%;
  top: 50%;
  width: var(--burst-size, 10px);
  height: var(--burst-size, 10px);
  border-radius: 999px;
  pointer-events: none;
  transform: translate(-50%, -50%);
  animation: read-burst 900ms cubic-bezier(0.18, 0.8, 0.24, 1) forwards;
}

@keyframes read-burst {
  0% {
    opacity: 0.95;
    transform: translate(-50%, -50%) scale(0.7) rotate(0deg);
  }

  100% {
    opacity: 0;
    transform:
      translate(
        calc(-50% + var(--burst-x)),
        calc(-50% + var(--burst-y))
      )
      scale(0.2)
      rotate(var(--burst-rotate));
  }
}

@keyframes direction-cue-down {
  0% {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.8);
  }

  20% {
    opacity: 1;
  }

  55% {
    opacity: 1;
    transform: translate(-50%, 6px) scale(1);
  }

  100% {
    opacity: 0;
    transform: translate(-50%, 20px) scale(1.08);
  }
}

@keyframes direction-cue-up {
  0% {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.8);
  }

  20% {
    opacity: 1;
  }

  55% {
    opacity: 1;
    transform: translate(-50%, -14px) scale(1);
  }

  100% {
    opacity: 0;
    transform: translate(-50%, -32px) scale(1.08);
  }
}

@keyframes card-read-exit {
  0% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }

  35% {
    transform: translateY(22px) scale(0.994);
    opacity: 0.97;
  }

  100% {
    transform: translateY(88px) scale(0.965);
    opacity: 0.72;
  }
}

@keyframes card-unread-exit {
  0% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }

  35% {
    transform: translateY(-18px) scale(1.004);
    opacity: 0.98;
  }

  100% {
    transform: translateY(-72px) scale(1.015);
    opacity: 0.9;
  }
}

@media (max-width: 640px) {
  header {
    padding-top: 24px;
  }

  .card {
    border-radius: 24px;
    padding: 22px;
  }
}