* {
  box-sizing: border-box;
}

:root {
  --bg-main: linear-gradient(135deg, #e0ecff 0%, #f8fbff 50%, #eef7f3 100%);
  --card-bg: rgba(255, 255, 255, 0.88);
  --text-main: #1f2a44;
  --text-muted: #5f6b85;
  --accent: #4f7cff;
  --accent-hover: #3d67dd;
  --danger: #ff5f6d;
  --danger-hover: #e14c59;
  --border: rgba(120, 145, 190, 0.25);
  --shadow: 0 12px 30px rgba(56, 84, 129, 0.15);
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Arial, sans-serif;
  color: var(--text-main);
  background: var(--bg-main);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 24px;
}

h1 {
  margin: 0 0 24px;
  font-size: 40px;
  text-align: center;
}

p {
  margin: 0 0 20px;
}

a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 700;
}

a:hover {
  text-decoration: underline;
}

ul {
  list-style: none;
  padding: 0;
  margin: 0;
  width: 100%;
  max-width: 420px;
}

li + li {
  margin-top: 14px;
}

ul a {
  display: block;
  text-align: center;
  padding: 16px 20px;
  border-radius: 16px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  font-size: 20px;
}

button {
  margin: 6px;
  padding: 14px 26px;
  min-width: 130px;
  border: none;
  border-radius: 14px;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  color: #fff;
  background: var(--accent);
  box-shadow: 0 8px 20px rgba(79, 124, 255, 0.25);
  transition: transform 0.2s ease, opacity 0.2s ease, background 0.2s ease;
}

button:hover:not(:disabled) {
  background: var(--accent-hover);
  transform: translateY(-2px);
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

button[data-stop] {
  background: var(--danger);
  box-shadow: 0 8px 20px rgba(255, 95, 109, 0.22);
}

button[data-stop]:hover:not(:disabled) {
  background: var(--danger-hover);
}

input {
  width: 100%;
  max-width: 280px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 14px;
  outline: none;
  font-size: 16px;
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow);
  margin-bottom: 18px;
}

.timer {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px;
  margin-top: 26px;
}

.field {
  min-width: 110px;
  padding: 18px 14px;
  border-radius: 18px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.value {
  font-size: 42px;
  font-weight: 700;
  line-height: 1;
  margin-bottom: 8px;
}

.label {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
}

.controls,
.buttons-row {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
}

.page-card {
  width: 100%;
  max-width: 720px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 24px;
  box-shadow: var(--shadow);
  padding: 28px;
  text-align: center;
}

@media (max-width: 600px) {
  body {
    padding: 16px;
  }

  h1 {
    font-size: 30px;
  }

  .page-card {
    padding: 20px;
  }

  .field {
    min-width: 92px;
  }

  .value {
    font-size: 34px;
  }

  button {
    width: 100%;
    max-width: 240px;
  }
}