:root {
  --bg-1: #f3f7ff;
  --bg-2: #fcfbf8;
  --ink: #24303a;
  --muted: #4f6170;
  --surface: #ffffff;
  --shadow: 0 14px 36px rgba(26, 42, 58, 0.12);
  --radius: 16px;
  --a: #e8f3ff;
  --b: #eaf9ef;
  --c: #fff2e4;
  --d: #f2f0fb;
  --line: #d8e2ed;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: "Avenir Next", "Trebuchet MS", "Gill Sans", sans-serif;
  background:
    radial-gradient(circle at 15% 10%, rgba(152, 188, 243, 0.26), transparent 45%),
    radial-gradient(circle at 85% 0%, rgba(247, 202, 146, 0.2), transparent 42%),
    linear-gradient(160deg, var(--bg-1), var(--bg-2));
  min-height: 100vh;
}

.app {
  width: min(1220px, 94vw);
  margin: 28px auto 42px;
}

.app-header {
  margin-bottom: 18px;
  animation: fade-in 520ms ease both;
}

.app-header h1 {
  margin: 0;
  font-size: clamp(1.85rem, 2.8vw, 2.5rem);
  letter-spacing: 0.02em;
  font-family: "Palatino Linotype", "Book Antiqua", serif;
}

.subtitle {
  margin: 10px 0 14px;
  color: var(--muted);
  max-width: 70ch;
}

.rule-box {
  padding: 12px 16px;
  border-radius: 12px;
  border: 1px solid #d7e6f8;
  background: linear-gradient(130deg, #f7fbff, #f4f9ff);
  box-shadow: 0 8px 24px rgba(26, 52, 86, 0.08);
}

.rule-box h2 {
  margin: 0 0 8px;
  font-size: 1.02rem;
}

.rule-box p {
  margin: 6px 0;
  color: #314557;
}

.rule-box code {
  font-family: "Consolas", "Courier New", monospace;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 14px 0 20px;
}

button {
  appearance: none;
  border: 1px solid #b8c8d8;
  background: linear-gradient(180deg, #ffffff, #f4f8fc);
  color: #1f2d3a;
  border-radius: 10px;
  padding: 10px 14px;
  cursor: pointer;
  font-size: 0.97rem;
  font-weight: 600;
  transition: transform 120ms ease, box-shadow 120ms ease, border-color 120ms ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 16px rgba(20, 41, 62, 0.12);
  border-color: #9cb4cc;
}

button:active {
  transform: translateY(0);
}

.matrix-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.matrix-card {
  border-radius: var(--radius);
  padding: 12px;
  box-shadow: var(--shadow);
  border: 1px solid rgba(80, 108, 136, 0.18);
  background: var(--surface);
  animation: slide-up 380ms ease both;
}

.matrix-card:nth-child(2) {
  animation-delay: 40ms;
}

.matrix-card:nth-child(3) {
  animation-delay: 80ms;
}

.matrix-card:nth-child(4) {
  animation-delay: 120ms;
}

.matrix-card h2 {
  margin: 0 0 8px;
  font-size: 1.05rem;
}

.card-a {
  background: linear-gradient(145deg, var(--a), #f6fbff 70%);
}

.card-b {
  background: linear-gradient(145deg, var(--b), #f7fef9 72%);
}

.card-c {
  background: linear-gradient(145deg, var(--c), #fff9f0 70%);
}

.card-d {
  background: linear-gradient(145deg, var(--d), #faf9fe 72%);
}

.matrix-body {
  display: grid;
  gap: 7px;
}

.matrix-layer {
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(135, 157, 180, 0.24);
  border-radius: 12px;
  padding: 6px;
}

.matrix-layer h3 {
  margin: 0 0 4px;
  font-size: 0.84rem;
  color: #3d5264;
}

.layer-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 4px;
}

.cell {
  display: block;
}

input[type="number"] {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 4px 3px;
  background: #ffffff;
  color: #203141;
  font-size: 0.8rem;
  text-align: center;
}

input[type="number"]:focus {
  outline: 2px solid #9bc2ec;
  border-color: #8ab6e5;
}

input[readonly] {
  background: #f7f9fd;
  color: #263849;
  border-color: #cfd9e6;
}

.explanation-section {
  margin-top: 18px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid rgba(80, 108, 136, 0.18);
  background: linear-gradient(145deg, #ffffff, #f8fbff 76%);
  padding: 16px;
  animation: fade-in 560ms ease both;
}

.explanation-section h2 {
  margin: 0 0 12px;
  font-size: 1.2rem;
}

.placeholder {
  margin: 0;
  color: #5d7182;
}

.calc-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.calc-block {
  border: 1px solid #d8e3ef;
  border-radius: 12px;
  padding: 10px 12px;
  background: #ffffff;
}

.calc-block h3 {
  margin: 0 0 6px;
  font-size: 0.98rem;
}

.calc-block p {
  margin: 4px 0;
  font-family: "Consolas", "Courier New", monospace;
  font-size: 0.9rem;
  color: #2a3b4b;
}

@media (min-width: 680px) {
  .matrix-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 1200px) {
  .matrix-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .controls {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  button {
    width: 100%;
  }
}

@keyframes fade-in {
  from {
    opacity: 0;
    transform: translateY(5px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slide-up {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}