:root {
  --color-bg-start: #f0f4f8;
  --color-bg-end: #d9e2ec;
  --color-primary: #4caf50;
  --color-primary-dark: #45a049;
  --color-secondary: #2196f3;
  --color-secondary-dark: #1976d2;
  --color-grey: #9e9e9e;
  --color-alert: #d32f2f;
  --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --spacing-small: 5px;
  --spacing-medium: 10px;
  --spacing-large: 20px;
  --border-radius: 8px;
  --transition-speed: 0.3s;
}

* {
  box-sizing: border-box;
}

body, html {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow: hidden;
  font-family: var(--font-family);
  background: linear-gradient(135deg, var(--color-bg-start), var(--color-bg-end));
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  background: #fff;
  padding: var(--spacing-large);
  margin: var(--spacing-large);
  border-radius: var(--border-radius);
  max-width: 800px;
  width: 100%;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  text-align: center;
  user-select: none;
  display: none; /* all screens hidden by default */
}

/* Visible screen */
.container.active {
  display: block;
}

/* Headings */
.heading {
  margin-top: 0;
}

/* Primary buttons */
button {
  appearance: none;
  border: none;
  border-radius: var(--border-radius);
  padding: var(--spacing-medium) var(--spacing-large);
  font-size: 1em;
  cursor: pointer;
  transition: background-color var(--transition-speed);
  margin: var(--spacing-small);
  color: #fff;
  background-color: var(--color-primary);
}

button:hover {
  background-color: var(--color-primary-dark);
}

/* Quick-preset buttons as secondary */
#preset-buttons .preset-btn {
  background-color: var(--color-secondary);
  display: inline-block;
}

#preset-buttons .preset-btn:hover {
  background-color: var(--color-secondary-dark);
}

/* Stop button as grey/alert */
#stop-btn {
  background-color: var(--color-grey);
}

#stop-btn:hover {
  background-color: var(--color-alert);
}

/* Numeric inputs */
input[type="number"] {
  padding: var(--spacing-small);
  margin: var(--spacing-small);
  font-size: 1em;
  width: 80px;
}

/* Results text */
#results {
  font-size: 1.2em;
  margin: var(--spacing-large) 0;
}

/* Full JSON dump */
pre {
  text-align: left;
  background: #f4f4f9;
  padding: var(--spacing-medium);
  border-radius: var(--border-radius);
  overflow-x: auto;
}

/* Progress bar */
#progress-bar-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 5px;
}

#progress-bar {
  height: 100%;
  width: 0%;
  background-color: var(--color-primary);
  transition: width 0.2s linear;
}

/* PANAS options */
.panas-options-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-small);
  margin-top: var(--spacing-large);
}

.panas-option-btn {
  margin: var(--spacing-small);
  padding: var(--spacing-medium);
  font-size: 1em;
  cursor: pointer;
  background-color: #b0bec5;
  border: 2px solid #78909c;
  border-radius: var(--border-radius);
  width: 90%;
  max-width: 300px;
  text-align: center;
  white-space: normal;
  line-height: 1.2;
  transition: background-color var(--transition-speed), border-color var(--transition-speed);
  color: #000;
}

.panas-option-btn:hover {
  background-color: #90a4ae;
  border-color: #546e7a;
}

/* Brain-fog options */
.brainfog-option-row {
  display: flex;
  justify-content: center;
  gap: var(--spacing-small);
  margin: var(--spacing-small) 0;
}

.brainfog-option-btn {
  padding: var(--spacing-medium);
  font-size: 1em;
  cursor: pointer;
  background-color: #b0bec5;
  border: 2px solid #78909c;
  border-radius: var(--border-radius);
  width: 40px;
  text-align: center;
  line-height: 1.2;
  transition: background-color var(--transition-speed), border-color var(--transition-speed);
  color: #000;
}

.brainfog-option-btn:hover {
  background-color: #90a4ae;
  border-color: #546e7a;
}

.brainfog-label-under {
  font-size: 0.9em;
  margin-top: var(--spacing-small);
  line-height: 1.3;
  white-space: pre-line;
}

.brainfog-label-under > div {
  display: flex;
  justify-content: space-between;
}

#label-left, #label-right {
  width: 30%;
}

#label-left {
  text-align: left;
}

#label-right {
  text-align: right;
}

#brainfog-mid-label {
  text-align: center;
  margin-top: var(--spacing-small);
}

#start-screen {
  display: block;
}