/* =========================================================
  ChemEquilibrium Lab - assets/css/layout.css
  ---------------------------------------------------------
  Layout utama aplikasi:
  - app shell dan screen system
  - home / landing page
  - header dan navigasi
  - mode simulasi
  - mode konsep
  - mode grafik
  - mode game
  - modal bantuan
  - responsive layout desktop, tablet, HP
========================================================= */

/* =========================================================
  Local Safe Variables
========================================================= */

:root {
  --container-max: 1440px;
  --content-max: 1180px;
  --control-panel-width: 380px;
  --home-card-min: 250px;
  --home-card-max: 330px;
}

/* =========================================================
  App Shell & Screen System
========================================================= */

.app-shell {
  width: 100%;
  min-height: 100vh;
  position: relative;
  isolation: isolate;
  background: var(--gradient-page);
}

.screen {
  width: 100%;
}

.home-screen,
.app-screen {
  animation: screenFadeIn var(--duration-slow) var(--ease-out);
}

.app-screen {
  display: none;
  min-height: calc(100vh - var(--header-height));
}

.app-screen.is-active {
  display: block;
}

@keyframes screenFadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* =========================================================
  Home / Landing Screen
========================================================= */

.home-screen {
  min-height: 100vh;
  display: none;
  place-items: center;
  padding: clamp(1.25rem, 4vw, 4rem);
  color: var(--text-main);
  background: var(--gradient-page);
  position: relative;
  overflow: hidden;
}

.home-screen.is-active {
  display: grid;
}

.home-bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  z-index: -1;
}

.bg-orb {
  position: absolute;
  display: block;
  border-radius: var(--radius-full);
  filter: blur(2px);
  opacity: 0.95;
}

.bg-orb-blue {
  width: 46rem;
  height: 46rem;
  left: -20rem;
  top: -20rem;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.32), transparent 68%);
}

.bg-orb-purple {
  width: 42rem;
  height: 42rem;
  right: -16rem;
  top: -14rem;
  background: radial-gradient(circle, rgba(168, 85, 247, 0.24), transparent 70%);
}

.bg-orb-orange {
  width: 38rem;
  height: 38rem;
  right: 18%;
  bottom: -20rem;
  background: radial-gradient(circle, rgba(249, 115, 22, 0.18), transparent 70%);
}

.floating-formula {
  position: absolute;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.55rem 1rem;
  border: 1px solid rgba(15, 23, 42, 0.08);
  border-radius: var(--radius-full);
  color: rgba(15, 23, 42, 0.48);
  background: rgba(255, 255, 255, 0.46);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(14px);
  font-weight: 950;
  letter-spacing: -0.02em;
  animation: softFloat 5s ease-in-out infinite;
}

.formula-one {
  left: 8%;
  top: 16%;
}

.formula-two {
  right: 12%;
  top: 34%;
  animation-delay: 900ms;
}

.formula-three {
  left: 12%;
  bottom: 16%;
  animation-delay: 1400ms;
}

@keyframes softFloat {
  0%,
  100% {
    transform: translateY(0) rotate(-1deg);
  }

  50% {
    transform: translateY(-14px) rotate(1deg);
  }
}

.home-content {
  width: min(var(--content-max), 100%);
  margin-inline: auto;
  position: relative;
  z-index: 1;
  text-align: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  margin-bottom: var(--space-3);
  padding: 0.35rem 0.8rem;
  border-radius: var(--radius-full);
  color: var(--primary);
  background: rgba(219, 234, 254, 0.8);
  border: 1px solid rgba(37, 99, 235, 0.12);
  font-size: var(--text-sm);
  font-weight: 950;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.eyebrow.dark {
  color: var(--secondary);
  background: rgba(243, 232, 255, 0.78);
  border-color: rgba(147, 51, 234, 0.12);
}

.home-title {
  margin-bottom: var(--space-4);
  color: var(--text-main);
  letter-spacing: -0.08em;
}

.home-subtitle {
  max-width: 820px;
  margin: 0 auto var(--space-8);
  color: var(--text-soft);
  font-size: clamp(var(--text-base), 1.7vw, var(--text-xl));
  line-height: var(--leading-relaxed);
}

.reaction-hero-card {
  width: min(680px, 100%);
  min-height: 82px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: clamp(var(--space-3), 3vw, var(--space-6));
  margin-bottom: var(--space-10);
  padding: var(--space-4) var(--space-6);
  border: 1px solid rgba(15, 23, 42, 0.08);
  border-radius: var(--radius-3xl);
  background: rgba(255, 255, 255, 0.78);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(18px);
}

.reactant-chip,
.product-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0.55rem 1.1rem;
  border-radius: var(--radius-full);
  color: var(--color-white);
  font-size: clamp(var(--text-lg), 2vw, var(--text-2xl));
  font-weight: 950;
  box-shadow: var(--shadow-md);
}

.chip-blue {
  background: var(--gradient-primary);
}

.chip-orange {
  background: var(--gradient-warning);
}

.equilibrium-arrow {
  color: var(--equilibrium);
  font-size: clamp(var(--text-3xl), 5vw, var(--text-5xl));
  font-weight: 950;
  text-shadow: 0 0 28px rgba(147, 51, 234, 0.22);
}

.mode-card-grid {
  width: min(100%, 1320px);
  margin-inline: auto;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(var(--space-4), 2vw, var(--space-6));
  align-items: stretch;
}

/* =========================================================
  Header / Navigation
========================================================= */

.app-header {
  min-height: var(--header-height);
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  display: grid;
  grid-template-columns: minmax(220px, 1fr) auto minmax(180px, 1fr);
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-3) clamp(var(--space-4), 2vw, var(--space-6));
  background: rgba(255, 255, 255, 0.82);
  border-bottom: 1px solid var(--border-soft);
  box-shadow: 0 8px 30px rgba(15, 23, 42, 0.06);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  min-width: 0;
}

.brand-icon {
  width: 46px;
  min-width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  border-radius: var(--radius-lg);
  color: var(--color-white);
  background: var(--gradient-equilibrium);
  box-shadow: var(--shadow-md), var(--shadow-glow-purple);
  font-size: var(--text-2xl);
  line-height: 1;
}

.brand strong {
  display: block;
  color: var(--text-main);
  font-size: var(--text-xl);
  line-height: 1.1;
  letter-spacing: -0.04em;
}

.brand small {
  display: block;
  color: var(--text-muted);
  font-size: var(--text-xs);
  font-weight: 750;
  letter-spacing: 0.02em;
}

.main-tabs {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: var(--space-1);
  border-radius: var(--radius-xl);
  background: rgba(15, 23, 42, 0.06);
  border: 1px solid rgba(15, 23, 42, 0.06);
  max-width: 100%;
  overflow-x: auto;
  scrollbar-width: none;
}

.main-tabs::-webkit-scrollbar {
  display: none;
}

.tab-button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0 var(--space-4);
  border-radius: var(--radius-lg);
  color: var(--slate-600);
  background: transparent;
  box-shadow: none;
  font-weight: 850;
  white-space: nowrap;
  transition:
    color var(--duration-fast) var(--ease-out),
    background-color var(--duration-fast) var(--ease-out),
    box-shadow var(--duration-fast) var(--ease-out),
    transform var(--duration-fast) var(--ease-out);
}

.tab-button:hover {
  transform: translateY(-1px);
  color: var(--primary);
  background: rgba(255, 255, 255, 0.66);
}

.tab-button.is-active {
  color: var(--primary);
  background: var(--color-white);
  box-shadow: var(--shadow-sm);
}

.header-actions {
  display: inline-flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--space-3);
}

/* =========================================================
  Main Content
========================================================= */

.app-main {
  width: 100%;
  min-height: calc(100vh - var(--header-height));
  padding: clamp(var(--space-3), 2vw, var(--space-6));
}

.workspace {
  width: min(var(--container-max), 100%);
  margin-inline: auto;
}

.lab-panel,
.info-card,
.graph-card,
.game-simulation-card,
.game-challenge-card {
  background: var(--surface);
  border: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(18px);
}

.lab-panel {
  position: relative;
  overflow: hidden;
}

.panel-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-5);
  padding: clamp(var(--space-4), 2vw, var(--space-6));
}

.section-description {
  max-width: 760px;
  margin-top: var(--space-2);
  color: var(--text-muted);
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.info-card {
  padding: var(--space-4);
}

/* =========================================================
  Simulation Mode Layout
========================================================= */

.simulation-workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) var(--control-panel-width);
  gap: clamp(var(--space-4), 2vw, var(--space-6));
  align-items: start;
}

.simulation-panel {
  min-height: 760px;
  background:
    radial-gradient(circle at 50% 40%, rgba(34, 211, 238, 0.16), transparent 34%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(239, 246, 255, 0.88));
}

.simulation-header {
  padding-bottom: var(--space-4);
}

.equilibrium-status {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.65rem 1rem;
  border-radius: var(--radius-full);
  color: var(--color-white);
  background: var(--gradient-secondary);
  box-shadow: var(--shadow-md), var(--shadow-glow-purple);
  font-weight: 900;
  white-space: nowrap;
}

.equilibrium-status.status-balanced {
  background: var(--gradient-success);
  box-shadow: var(--shadow-md), 0 0 32px rgba(22, 163, 74, 0.28);
}

.equilibrium-status.status-moving {
  background: var(--gradient-warning);
}

.reaction-equation-card {
  width: min(720px, calc(100% - var(--space-8)));
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(var(--space-3), 2vw, var(--space-6));
  margin: 0 auto var(--space-5);
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-2xl);
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--border-soft);
  box-shadow: var(--shadow-md);
}

.formula-token {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-full);
  color: var(--color-white);
  font-size: clamp(var(--text-lg), 2vw, var(--text-2xl));
  font-weight: 950;
  white-space: nowrap;
}

.formula-reactant {
  background: var(--gradient-primary);
}

.formula-product {
  background: var(--gradient-warning);
}

.reaction-arrow {
  color: var(--equilibrium);
  font-size: clamp(var(--text-3xl), 4vw, var(--text-5xl));
  font-weight: 950;
}

.simulation-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 360px;
  gap: var(--space-5);
  padding: 0 var(--space-5) var(--space-5);
}

.vessel-card {
  min-height: 610px;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.vessel-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.rate-pills {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.rate-pills span {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0.35rem 0.65rem;
  border-radius: var(--radius-full);
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid var(--border-soft);
  font-size: var(--text-sm);
  font-weight: 800;
}

.reaction-vessel {
  flex: 1;
  min-height: 500px;
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-3xl);
  border: 2px solid rgba(37, 99, 235, 0.18);
  background:
    radial-gradient(circle at 28% 28%, rgba(255, 255, 255, 0.74), transparent 24%),
    linear-gradient(135deg, rgba(219, 234, 254, 0.72), rgba(243, 232, 255, 0.54), rgba(255, 237, 213, 0.56));
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.6), var(--shadow-md);
}

.particle-canvas {
  width: 100%;
  height: 100%;
}

.vessel-overlay {
  position: absolute;
  inset: var(--space-4);
  pointer-events: none;
}

.vessel-label {
  position: absolute;
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
  color: var(--color-white);
  font-size: var(--text-xs);
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  opacity: 0.86;
}

.reactant-label {
  left: 0;
  top: 0;
  background: var(--reactant);
}

.product-label {
  right: 0;
  top: 0;
  background: var(--product);
}

.vessel-legend {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--space-3);
  color: var(--text-muted);
  font-size: var(--text-sm);
  font-weight: 800;
}

.vessel-legend span {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.legend-dot {
  width: 13px;
  height: 13px;
  border-radius: var(--radius-full);
  display: inline-block;
}

.reactant-dot {
  background: var(--reactant);
}

.product-dot {
  background: var(--product);
}

.collision-dot {
  background: var(--equilibrium);
}

.simulation-side-stack,
.control-panel-stack {
  display: grid;
  gap: var(--space-4);
  align-content: start;
}

.metric-list {
  display: grid;
  gap: var(--space-2);
}

.metric-list > div {
  min-height: 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  padding: var(--space-3);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.68);
  border: 1px solid var(--border-soft);
}

.metric-list dt {
  color: var(--text-muted);
  font-weight: 800;
}

.metric-list dd {
  color: var(--text-main);
  font-weight: 950;
  text-align: right;
}

.concentration-bars {
  display: grid;
  gap: var(--space-4);
}

.concentration-row {
  display: grid;
  grid-template-columns: 64px 1fr 76px;
  align-items: center;
  gap: var(--space-3);
  color: var(--text-muted);
  font-weight: 850;
}

.bar-track {
  height: 14px;
  border-radius: var(--radius-full);
  background: rgba(15, 23, 42, 0.08);
  overflow: hidden;
}

.bar-fill {
  width: 50%;
  height: 100%;
  border-radius: inherit;
  transition: width var(--duration-slow) var(--ease-out);
}

.reactant-fill {
  background: var(--gradient-primary);
}

.product-fill {
  background: var(--gradient-warning);
}

.control-card {
  position: sticky;
  top: calc(var(--header-height) + var(--space-4));
}

.explanation-card {
  position: static;
}

.control-group {
  display: grid;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-top: 1px solid var(--border-soft);
}

.control-group:first-of-type {
  border-top: 0;
  padding-top: 0;
}

.button-grid {
  display: grid;
  gap: var(--space-3);
}

.button-grid.two-columns {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.range-control {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: var(--space-3);
  color: var(--text-muted);
  font-size: var(--text-sm);
  font-weight: 800;
}

.toggle-row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--text-main);
  font-weight: 850;
}

.explanation-text {
  line-height: var(--leading-relaxed);
}

/* =========================================================
  Concept Mode Layout
========================================================= */

.concept-panel {
  min-height: 760px;
  padding-bottom: var(--space-6);
  background:
    radial-gradient(circle at 20% 20%, rgba(168, 85, 247, 0.16), transparent 32%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(250, 245, 255, 0.82));
}

.concept-card-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
  padding: 0 var(--space-5) var(--space-5);
}

.concept-animation-stage {
  margin: 0 var(--space-5);
  padding: clamp(var(--space-5), 4vw, var(--space-10));
  border-radius: var(--radius-3xl);
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--border-soft);
  box-shadow: var(--shadow-md);
}

.rate-balance {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px minmax(0, 1fr);
  align-items: center;
  gap: var(--space-6);
}

.rate-column,
.balance-center {
  display: grid;
  justify-items: center;
  gap: var(--space-3);
  text-align: center;
}

.rate-arrow {
  width: 88px;
  height: 88px;
  display: grid;
  place-items: center;
  border-radius: var(--radius-full);
  color: var(--color-white);
  background: var(--gradient-primary);
  box-shadow: var(--shadow-md), var(--shadow-glow-blue);
  font-size: var(--text-5xl);
  font-weight: 950;
}

.reverse-rate .rate-arrow {
  background: var(--gradient-warning);
  box-shadow: var(--shadow-md), var(--shadow-glow-orange);
}

.balance-scale {
  font-size: 5rem;
  animation: softPulse 2.8s ease-in-out infinite;
}

@keyframes softPulse {
  0%,
  100% {
    transform: scale(1);
    filter: drop-shadow(0 0 0 rgba(147, 51, 234, 0));
  }

  50% {
    transform: scale(1.06);
    filter: drop-shadow(0 14px 22px rgba(147, 51, 234, 0.22));
  }
}

.rate-meter {
  width: min(220px, 100%);
  height: 16px;
  border-radius: var(--radius-full);
  background: rgba(15, 23, 42, 0.08);
  overflow: hidden;
}

.rate-meter span {
  display: block;
  width: 64%;
  height: 100%;
  border-radius: inherit;
  background: var(--gradient-equilibrium);
}

/* =========================================================
  Graph Mode Layout
========================================================= */

.graph-panel {
  min-height: 760px;
  padding-bottom: var(--space-5);
  background:
    radial-gradient(circle at 80% 18%, rgba(34, 211, 238, 0.14), transparent 34%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(236, 254, 255, 0.78));
}

.graph-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
}

.graph-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-5);
  padding: 0 var(--space-5) var(--space-5);
}

.graph-card {
  padding: var(--space-4);
}

.graph-canvas {
  width: 100%;
  height: 420px;
  border-radius: var(--radius-xl);
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--border-soft);
}

/* =========================================================
  Game Mode Layout
========================================================= */

.game-menu {
  display: none;
  min-height: calc(100vh - var(--header-height) - var(--space-12));
  place-items: center;
  padding: clamp(var(--space-6), 4vw, var(--space-12));
}

.game-menu.is-active {
  display: grid;
}

.game-menu-content {
  width: min(1120px, 100%);
  text-align: center;
}

.game-menu-content .section-description {
  margin: var(--space-4) auto var(--space-10);
}

.level-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(var(--space-4), 2vw, var(--space-6));
}

.game-play {
  width: min(var(--container-max), 100%);
  margin-inline: auto;
}

.game-status-bar {
  display: grid;
  grid-template-columns: repeat(5, auto) auto;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-6);
  border-radius: var(--radius-2xl);
  color: var(--color-white);
  background: var(--gradient-secondary);
  box-shadow: var(--shadow-lg), var(--shadow-glow-purple);
}

.game-status-bar p {
  color: var(--color-white);
  font-weight: 800;
  white-space: nowrap;
}

.game-status-bar strong {
  color: var(--amber-300);
  font-weight: 950;
}

.game-board {
  min-height: 650px;
  display: grid;
  grid-template-columns: minmax(420px, 0.9fr) minmax(0, 1.1fr);
  gap: var(--space-5);
  align-items: stretch;
  margin-top: var(--space-5);
  padding: var(--space-5);
  border-radius: var(--radius-3xl);
  background: rgba(255, 253, 220, 0.82);
  border: 1px solid rgba(255, 255, 255, 0.76);
  box-shadow: var(--shadow-lg);
}

.game-simulation-card,
.game-challenge-card {
  min-height: 560px;
  position: relative;
  overflow: hidden;
  padding: var(--space-5);
}

.game-system-summary {
  position: absolute;
  left: var(--space-4);
  right: var(--space-4);
  bottom: var(--space-4);
  display: flex;
  justify-content: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  padding: var(--space-3);
  border-radius: var(--radius-xl);
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid var(--border-soft);
  color: var(--text-muted);
  font-size: var(--text-sm);
  font-weight: 800;
}

/* =========================================================
  Help Modal Layout
========================================================= */

.help-modal {
  width: min(640px, calc(100vw - 2rem));
  max-height: calc(100vh - 2rem);
  margin: auto;
  background: transparent;
  color: var(--text-main);
}

.help-modal::backdrop {
  background: rgba(2, 6, 23, 0.58);
  backdrop-filter: blur(7px);
}

.modal-card {
  width: 100%;
  overflow: hidden;
  border-radius: var(--radius-2xl);
  background: var(--color-white);
  box-shadow: var(--shadow-xl);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-5);
  border-bottom: 1px solid var(--border-soft);
}

.modal-header h2 {
  font-size: var(--text-2xl);
}

.modal-body {
  display: grid;
  gap: var(--space-3);
  padding: var(--space-5);
}

.modal-body p {
  color: var(--text-muted);
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
}

/* =========================================================
  Responsive Layout
========================================================= */

@media (max-width: 1360px) {
  :root {
    --control-panel-width: 360px;
  }

  .simulation-grid {
    grid-template-columns: minmax(0, 1fr) 320px;
  }

  .concept-card-grid,
  .level-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 1180px) {
  .app-header {
    grid-template-columns: 1fr;
    justify-items: stretch;
  }

  .brand,
  .header-actions {
    justify-content: center;
  }

  .main-tabs {
    width: 100%;
    justify-content: flex-start;
  }

  .simulation-workspace {
    grid-template-columns: 1fr;
  }

  .control-panel-stack {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .control-card,
  .explanation-card {
    position: static;
  }

  .graph-grid,
  .game-board {
    grid-template-columns: 1fr;
  }

  .game-status-bar {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .game-status-bar .btn {
    grid-column: 1 / -1;
  }
}

@media (max-width: 980px) {
  .mode-card-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .simulation-grid {
    grid-template-columns: 1fr;
  }

  .simulation-side-stack {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .rate-balance {
    grid-template-columns: 1fr;
  }

  .concept-card-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 760px) {
  .home-screen {
    min-height: 100vh;
    padding: var(--space-6) var(--space-4);
  }

  .floating-formula {
    display: none;
  }

  .home-title {
    letter-spacing: -0.06em;
  }

  .home-subtitle {
    margin-bottom: var(--space-6);
  }

  .reaction-hero-card {
    flex-direction: column;
    gap: var(--space-2);
    margin-bottom: var(--space-6);
  }

  .mode-card-grid {
    grid-template-columns: 1fr;
  }

  .app-header {
    position: relative;
    gap: var(--space-3);
    padding: var(--space-3);
  }

  .brand {
    justify-content: flex-start;
  }

  .brand-icon {
    width: 40px;
    min-width: 40px;
    height: 40px;
  }

  .brand strong {
    font-size: var(--text-lg);
  }

  .brand small {
    display: none;
  }

  .header-actions {
    justify-content: stretch;
  }

  .header-actions .btn {
    flex: 1;
  }

  .app-main {
    padding: var(--space-3);
  }

  .panel-header {
    display: grid;
    gap: var(--space-4);
  }

  .equilibrium-status {
    justify-self: start;
  }

  .simulation-panel,
  .concept-panel,
  .graph-panel {
    min-height: auto;
  }

  .reaction-equation-card {
    width: calc(100% - var(--space-6));
    flex-direction: column;
    gap: var(--space-2);
  }

  .simulation-grid,
  .control-panel-stack,
  .simulation-side-stack {
    grid-template-columns: 1fr;
    padding-inline: var(--space-3);
  }

  .vessel-card {
    min-height: 520px;
  }

  .vessel-toolbar {
    display: grid;
  }

  .reaction-vessel {
    min-height: 420px;
  }

  .button-grid.two-columns {
    grid-template-columns: 1fr;
  }

  .concept-card-grid,
  .level-grid {
    grid-template-columns: 1fr;
    padding-inline: var(--space-3);
  }

  .concept-animation-stage {
    margin-inline: var(--space-3);
  }

  .graph-grid {
    grid-template-columns: 1fr;
    padding-inline: var(--space-3);
  }

  .graph-actions {
    width: 100%;
  }

  .graph-actions .btn {
    flex: 1;
  }

  .graph-canvas {
    height: 320px;
  }

  .game-status-bar {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    padding: var(--space-4);
  }

  .game-board {
    min-height: auto;
    padding: var(--space-3);
  }

  .game-simulation-card,
  .game-challenge-card {
    min-height: 430px;
    padding: var(--space-4);
  }
}

@media (max-width: 520px) {
  .main-tabs {
    gap: 0;
  }

  .tab-button {
    padding-inline: var(--space-3);
    font-size: var(--text-sm);
  }

  .reaction-hero-card {
    padding: var(--space-4);
  }

  .concentration-row {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }

  .range-control {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }

  .game-status-bar {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .game-system-summary {
    position: static;
    margin-top: var(--space-3);
  }
}