/* GLOBAL RESET & ROOT VARIABLES */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: Roboto, "Segoe UI", -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
}

:root {
  /* Colors */
  --bg: #f7f7f7;
  --text: #222222;
  --white: #ffffff;
  --shadow: rgba(0, 0, 0, 0.1);
  --accent-orange: #da6e00;
  --accent-orange-hover: #d05d28;
  --accent-orange-active: #ba2721;
  --accent-green: #61993b;
  --accent-green-hover: #587f40;
  --slider-track: #CCCCCC;
  --slider-fill: #4D4D4D;
  --slider-thumb: #A2A2A2;
  --slider-thumb-hover: #777777;

  /* Layout */
  --max-width: 520px;
  --radius: 12px;
  --transition: 0.2s ease;
}

/* BASE STYLES */
html,
body {
  height: 100%;
}

body {
  background: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  padding: 16px;
}

/* CONTAINER */
.container {
  background-color: var(--white);
  padding: 10px;
  border-radius: var(--radius);
  box-shadow: 0 4px 10px var(--shadow);
  width: 100%;
  max-width: var(--max-width);
  text-align: center;
  margin: auto;
}

/* TYPOGRAPHY */
h1 {
  font-size: 22px;
  margin-bottom: 20px;
  color: var(--text);
  font-weight: 700;
}

label {
  display: flex;
  justify-content: space-between;
  font-size: 16px;
  margin-bottom: 6px;
  color: var(--text);
  font-weight: 600;
}

/* TIMER */
.timer {
  font-size: 5.0rem;
  font-weight: 700;
  margin-bottom: 10px;
}

#timer {
  display: block;
  margin-top: 0px;
  font-size: 5.0rem;;
  font-weight: 700;
  color: var(--text);
}

.roundReps {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 10px;
}

#roundReps {
  display: block;
  margin-top: 0px;
  font-size: 2.5rem;;
  font-weight: 700;
  color: var(--text);
}

/* SLIDERS */
.slider-container {
  margin: 10px 0;
  text-align: left;
}

.slider {
  width: 100%;
  height: 8px;
  appearance: none;
  outline: none;
  border-radius: 5px;
  background: linear-gradient(
    to right,
    var(--slider-fill) 0%,
    var(--slider-fill) var(--value, 0%),
    var(--slider-track) var(--value, 0%),
    var(--slider-track) 100%
  );
  transition: background var(--transition);
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  background-color: var(--slider-thumb);
  border-radius: 50%;
  cursor: pointer;
  transition: background var(--transition);
  margin-top: -7px;
}

.slider::-webkit-slider-thumb:hover {
  background-color: var(--slider-thumb-hover);
}

.slider::-moz-range-thumb {
  width: 22px;
  height: 22px;
  background-color: var(--slider-thumb);
  border-radius: 50%;
  cursor: pointer;
  border: none;
  transition: background var(--transition);
}

.slider::-moz-range-thumb:hover {
  background-color: var(--slider-thumb-hover);
}

/* BUTTONS */
button {
  width: 100%;
  padding: 14px 20px;
  border: none;
  border-radius: 8px;
  font-size: 20px;
  font-weight: 600;
  color: var(--white);
  cursor: pointer;
  transition: background var(--transition), transform 0.1s ease;
}

button:active {
  transform: scale(0.97);
}

/* Primary Exercise Button */
#exercise-btn {
  background-color: var(--accent-orange);
  margin-bottom: 10px;
}
#exercise-btn:hover {
  background-color: var(--accent-orange-hover);
}

/* Keep Settings Button */
#keep-settings-btn {
  background-color: var(--accent-orange);
  margin-top: 0px;
}
#keep-settings-btn.active {
  background-color: var(--accent-orange-active);
}
#keep-settings-btn:hover {
  background-color: var(--accent-orange-active);
}

/* Start Button */
#start-btn {
  background-color: var(--accent-green);
  margin-top: 0px;
  margin-bottom: 10px;
}
#start-btn:hover {
  background-color: var(--accent-green-hover);
}

/* RESPONSIVE DESIGN */
@media (max-width: 480px) {
  .container {
    padding: 16px;
    border-radius: 10px;
  }

  h1 {
    font-size: 20px;
  }

  label {
    font-size: 15px;
  }

  button {
    font-size: 16px;
    padding: 12px;
  }

  .slider::-webkit-slider-thumb,
  .slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
  }
}