:root {
  --bg: #000000;
  --panel: #080808;
  --panel-soft: #111111;
  --panel-strong: #151515;
  --line: rgba(255, 255, 255, 0.08);
  --line-strong: rgba(255, 255, 255, 0.16);
  --text: #ffffff;
  --muted: #a1a1aa;
  --accent: #ffffff;
  --good: #8df0b3;
  --bad: #ff9292;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.42);
}

* {
  box-sizing: border-box;
}

html {
  color-scheme: dark;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.04), transparent 18rem),
    linear-gradient(180deg, #000000 0%, #050505 100%);
  color: var(--text);
  font-family: "Manrope", sans-serif;
}

.confetti-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 30;
}

button,
input {
  font: inherit;
}

button {
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 0.95rem 1.2rem;
  background: #ffffff;
  color: #000000;
  font-weight: 700;
  cursor: pointer;
  transition: transform 320ms ease, background 320ms ease, opacity 320ms ease, border-color 320ms ease;
}

button:hover {
  transform: translateY(-2px) scale(1.01);
}

button.secondary,
.set-button {
  background: var(--panel-soft);
  color: var(--text);
}

button.secondary:hover,
.set-button:hover {
  background: #171717;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

input {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: 20px;
  padding: 1rem 1.05rem;
  background: #0e0e0e;
  color: #ffffff;
  outline: none;
  transition: border-color 320ms ease, transform 320ms ease;
}

input:focus {
  border-color: rgba(255, 255, 255, 0.4);
  transform: translateY(-1px);
}

label {
  display: grid;
  gap: 0.5rem;
  color: var(--text);
}

.hidden {
  display: none !important;
}

.eyebrow {
  margin: 0 0 0.4rem;
  color: var(--muted);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.gate-overlay {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 1.5rem;
  background: rgba(0, 0, 0, 0.74);
  backdrop-filter: blur(12px);
  z-index: 10;
}

.gate-card,
.vault-panel,
.intro-panel,
.study-shell,
.stat-pill,
.set-button,
.study-card,
.summary-card {
  background: rgba(10, 10, 10, 0.96);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.gate-card {
  width: min(100%, 420px);
  padding: 2rem;
  border-radius: 30px;
  animation: rise 760ms ease;
}

.gate-card h1,
.vault-panel h1,
.intro-panel h2,
.study-head h2,
.study-card h3 {
  margin: 0;
  font-family: "Sora", sans-serif;
  font-weight: 700;
  letter-spacing: -0.04em;
}

.gate-copy,
.vault-copy {
  color: var(--muted);
}

.gate-form {
  display: grid;
  gap: 1rem;
}

.error-message {
  min-height: 1.4rem;
  color: var(--bad);
}

.app-shell {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: 1.2rem;
  min-height: 100vh;
  padding: 1.2rem;
}

.vault-panel {
  position: sticky;
  top: 1.2rem;
  align-self: start;
  padding: 1.1rem;
  border-radius: 30px;
  animation: rise 880ms ease;
}

.vault-panel h1 {
  font-size: 2.6rem;
}

.set-list {
  display: grid;
  gap: 0.8rem;
  margin-top: 1rem;
}

.set-button {
  width: 100%;
  border-radius: 24px;
  padding: 1rem;
  text-align: left;
  animation: rise 760ms ease;
}

.set-button.active {
  border-color: rgba(255, 255, 255, 0.3);
  background: #161616;
}

.set-button-title {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.45rem;
  color: #ffffff;
  font-weight: 700;
}

.set-meta {
  color: var(--muted);
  font-size: 0.94rem;
}

.study-stage {
  display: grid;
  align-content: start;
}

.intro-panel,
.study-shell {
  border-radius: 34px;
  padding: 1.3rem;
}

.intro-panel {
  min-height: 240px;
  display: grid;
  place-items: center;
  text-align: center;
  animation: rise 980ms ease;
}

.study-shell {
  animation: fadeIn 620ms ease;
}

.study-head {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 1rem;
}

.study-head h2 {
  font-size: clamp(2rem, 4vw, 3.4rem);
}

.stats-row,
.study-meta,
.card-actions,
.summary-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.stats-row {
  justify-content: flex-end;
}

.stat-pill {
  min-width: 96px;
  padding: 0.75rem 0.95rem;
  border-radius: 22px;
  animation: rise 980ms ease;
}

.stat-pill span {
  display: block;
  font-size: 1.35rem;
  font-weight: 800;
  color: #ffffff;
}

.stat-pill small {
  color: var(--muted);
}

.study-meta {
  margin: 1rem 0 1.1rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.45rem 0.75rem;
  border-radius: 999px;
  background: #171717;
  color: #ffffff;
  border: 1px solid var(--line);
}

.badge.muted {
  color: var(--muted);
}

.study-content {
  display: grid;
}

.study-card,
.summary-card {
  border-radius: 30px;
  padding: 1.3rem;
}

.study-card {
  min-height: 440px;
  display: grid;
  gap: 1rem;
  align-content: space-between;
  animation: cardIn 520ms ease;
}

.study-card-immersive {
  background:
    radial-gradient(circle at top right, rgba(141, 240, 179, 0.08), transparent 16rem),
    linear-gradient(180deg, rgba(12, 12, 12, 0.98), rgba(8, 8, 8, 0.98));
  border-color: rgba(255, 255, 255, 0.14);
}

.card-face {
  min-height: 250px;
  display: grid;
  place-items: center;
  padding: 1.2rem;
  border-radius: 26px;
  background: #121212;
  border: 1px solid var(--line);
  color: #ffffff;
  text-align: center;
  font-size: clamp(1.5rem, 3.4vw, 2.5rem);
  font-weight: 800;
  line-height: 1.15;
  animation: pulseIn 560ms ease;
}

.card-button {
  width: 100%;
  cursor: pointer;
}

.card-button:hover {
  background: #181818;
  box-shadow: none;
  transform: scale(1.01);
}

.subtle-copy {
  margin: 0;
  color: var(--muted);
}

.strong-copy {
  color: #d4d4d8;
}

.feedback-good {
  color: var(--good);
}

.feedback-bad {
  color: var(--bad);
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.9rem;
}

.memory-strip,
.diagram-panel,
.memory-status {
  border: 1px solid var(--line);
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.03);
}

.memory-strip {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.9rem 1rem;
}

.memory-strip p {
  margin: 0;
  color: #f4f4f5;
}

.memory-chip {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 0.35rem 0.7rem;
  background: rgba(141, 240, 179, 0.12);
  color: var(--good);
  font-size: 0.82rem;
  font-weight: 700;
  white-space: nowrap;
}

.memory-status {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  padding: 0.9rem 1rem;
}

.memory-status p {
  margin: 0;
  color: var(--muted);
}

.diagram-panel {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
}

.diagram-block {
  display: grid;
  gap: 0.6rem;
}

.diagram-title {
  margin: 0;
  color: #ffffff;
  font-weight: 700;
}

.diagram-arrow {
  color: var(--muted);
  font-size: 1.4rem;
  font-weight: 800;
}

.particle-grid {
  min-height: 120px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.9rem;
  padding: 1rem;
  border-radius: 22px;
  background: #0f0f0f;
  border: 1px solid var(--line);
}

.particle-grid.tight {
  gap: 0.28rem;
}

.particle-grid span {
  aspect-ratio: 1;
  border-radius: 999px;
  background: linear-gradient(180deg, #ffffff, #d4d4d8);
  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.08);
}

.summary-card strong {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 1.9rem;
  color: #ffffff;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes cardIn {
  from {
    opacity: 0;
    transform: translateY(10px) scale(0.99);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes pulseIn {
  from {
    opacity: 0;
    transform: scale(0.985);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@media (max-width: 920px) {
  .app-shell,
  .summary-grid {
    grid-template-columns: 1fr;
  }

  .vault-panel {
    position: static;
  }

  .study-head {
    flex-direction: column;
    align-items: stretch;
  }

  .stats-row {
    justify-content: flex-start;
  }

  .diagram-panel {
    grid-template-columns: 1fr;
  }
}