:root {
      --primary-color: #800080;
      --primary-light: #a64da6;
      --primary-dark: #660066;
      --text-color: #fff;
      --container-bg: rgba(255, 255, 255, 0.08);
    }
    html, body {
      min-height: 100vh;
      width: 100vw;
      margin: 0;
      padding: 0;
      background: linear-gradient(135deg, #1a0022 0%, #2c003e 70%, #800080 100%);
      color: var(--text-color);
      font-family: 'Montserrat', sans-serif;
      overflow-x: hidden;
      touch-action: manipulation;
      -webkit-tap-highlight-color: transparent;
    }
    main {
      min-height: 100vh;
      width: 100vw;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      padding: 0;
      gap: 20px;
    }
    header {
      margin-top: 2vh;
      text-align: center;
    }
    h1 {
      font-size: clamp(1.4rem, 6vw, 2.3rem);
      margin-bottom: 18px;
      letter-spacing: 2px;
    }
    .timer-section {
      display: flex;
      flex-direction: column;
      align-items: center;
      margin-bottom: 18px;
      width: 100vw;
      max-width: 600px;
    }
    .timer-container {
      position: relative;
      width: 98vw;
      max-width: 450px;
      aspect-ratio: 1 / 1;
      margin-bottom: 18px;
      min-width: 180px;
    }
    .timer-container svg {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      min-width: 0;
      min-height: 0;
      transform: rotate(-90deg);
      user-select: none;
      touch-action: none;
    }
    #progressCircle {
      stroke: var(--primary-light);
      stroke-width: 36;
      fill: transparent;
      transition: stroke-dashoffset 0.25s linear;
    }
    #countdown {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      transform-origin: center;
      font-size: clamp(2rem, 16vw, 7rem);
      font-weight: bold;
      transition: transform 0.2s ease;
      letter-spacing: 2px;
      text-align: center;
      width: 98%;
      word-break: break-word;
      user-select: none;
      pointer-events: none;
      line-height: 1.05;
    }
    @keyframes throb {
      0% { transform: translate(-50%, -50%) scale(1); }
      50% { transform: translate(-50%, -50%) scale(1.1); }
      100% { transform: translate(-50%, -50%) scale(1); }
    }
    .throb { animation: throb 1s ease; }
    .session-progress-container {
      width: 100%;
      max-width: 450px;
      background: #4b0082;
      height: clamp(22px, 8vw, 68px);
      overflow: hidden;
      margin-bottom: 14px;
      position: relative;
      border-radius: 13px;
    }
    .progress-bar {
      height: 100%;
      width: 0%;
      transition: width 0.3s cubic-bezier(.7,0,.35,1.1);
      position: absolute;
      left: 0;
      top: 0;
      z-index: 2;
      background: linear-gradient(135deg, #a64da6 80%, #fff6 100%);
      box-shadow: 0 0 18px 4px #fff7, 0 0 12px 3px #ffd70055, 0 0 7px 2px #a64da6a0;
      border-radius: 0;
    }
    #barTwinkleContainer {
      pointer-events: none;
      position: absolute;
      left: 0; top: 0;
      width: 100%; height: 100%;
      z-index: 3;
    }
    .twinkle-star {
      position: absolute;
      width: 18px; height: 18px;
      opacity: 0;
      pointer-events: none;
      filter: drop-shadow(0 0 5px #fffadf) drop-shadow(0 0 2px #fffacd);
      transition: opacity 0.38s cubic-bezier(.75,0,.5,1.6), transform 0.8s;
      will-change: opacity, transform;
    }
    .twinkle-star svg {
      width: 100%; height: 100%;
      display: block;
    }
    #switchMsg {
      font-size: clamp(1.2rem, 6vw, 2.8rem);
      font-weight: 800;
      color: #ffd700;
      text-shadow: 1px 2px 22px #800080a0,0 0 30px #fff, 2px 2px 0 #000;
      background: rgba(0,0,0,0.20);
      border-radius: 16px;
      padding: 12px 22px;
      text-align: center;
      margin-bottom: 24px;
      margin-top: 6px;
      display: none;
      transition: opacity 0.3s;
      letter-spacing: 0.03em;
      box-shadow: 0 0 8px 3px #fff2;
    }
    #sessionPercentage {
      font-weight: bold;
      margin-bottom: 18px;
      text-align: center;
      letter-spacing: 1px;
      font-size: clamp(0.8rem, 5vw, 2.9rem);
      word-break: break-word;
    }
    .controls {
      display: flex;
      flex-direction: row;
      gap: 14px;
      justify-content: center;
      align-items: center;
      max-width: 430px;
      width: 100%;
      margin: 18px auto 8px auto;
    }
    .controls button {
      flex: 1;
      min-width: 0;
      width: 100%;
      padding: clamp(8px, 3vw, 20px) 0;
      font-size: clamp(1rem, 3.5vw, 1.25rem);
      font-weight: 700;
      background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
      border: none;
      border-radius: 14px;
      color: var(--text-color);
      cursor: pointer;
      box-shadow: 0 2px 5px rgba(0,0,0,0.18);
      letter-spacing:1px;
      transition: transform 0.2s, background 0.28s, color 0.18s;
      margin: 0;
      display: block;
      outline: none;
      user-select: none;
    }
    .controls button:active { transform: scale(0.98);}
    .controls button:hover {
      background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
    }
    .controls button.stop-active {
      background: linear-gradient(135deg, #d72631, #ff2222);
      color: #fff;
    }
    @media (max-width: 600px) {
      .timer-section { margin-bottom: 8px; }
      .session-progress-container { margin-bottom: 8px;}
      .controls { flex-direction: column; gap: 7px; max-width: 99vw;}
    }
    .settings-presets-container {
      display: flex;
      flex-wrap: wrap;
      gap: 20px;
      justify-content: center;
      width: 100%;
      margin-bottom: 10px;
      transition: opacity 0.5s, transform 0.5s;
    }
    .settings-presets-container.hide {
      opacity: 0;
      transform: translateY(-40px) scale(0.99);
      pointer-events: none;
      filter: blur(3px);
      transition: opacity 0.4s, transform 0.5s, filter 0.5s;
    }
    .settings, .presets-container {
      width: 100%;
      max-width: 320px;
      text-align: center;
      background: var(--container-bg);
      border-radius: 12px;
      padding: 16px;
      box-shadow: 0 4px 8px rgba(0,0,0,0.18);
    }
    .settings h2, .presets-container h2 {
      font-size: 1rem;
      margin-bottom: 8px;
      font-weight: bold;
    }
    .slider-group {
      margin: 9px 0;
      text-align: left;
    }
    .slider-group label {
      display: block;
      margin-bottom: 3px;
      font-weight: bold;
      font-size: 0.95rem;
    }
    .slider-group input[type="range"] {
      width: 100%;
      cursor: pointer;
      accent-color: #dda0dd;
      height: 24px;
      background: transparent;
      touch-action: pan-x;
    }
    .settings button {
      margin-top: 8px;
      padding: 7px 11px;
      font-size: 1rem;
      background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
      border: none;
      border-radius: 10px;
      color: var(--text-color);
      cursor: pointer;
      box-shadow: 0 2px 5px rgba(0,0,0,0.18);
      transition: transform 0.2s, background 0.3s;
    }
    .settings button:hover {
      transform: scale(1.03);
      background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
    }
    .presets-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px;
    }
    .preset-btn {
      padding: 8px;
      font-size: 1rem;
      background: linear-gradient(135deg, #6a0dad, #800080);
      border: none;
      border-radius: 10px;
      color: var(--text-color);
      cursor: pointer;
      transition: transform 0.2s, background 0.3s;
      box-shadow: 0 2px 5px rgba(0,0,0,0.14);
    }
    .preset-btn:hover {
      transform: scale(1.03);
      background: linear-gradient(135deg, #800080, #a64ca6);
    }
    #confettiMsg {
      position: fixed;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      z-index: 10000;
      color: #fff;
      font-size: clamp(1.2rem, 7vw, 5vw);
      font-family: 'Montserrat',sans-serif;
      text-shadow: 4px 8px 38px #800080,0 0 30px #fff, 0 0 20px #00f, 2px 2px 0 #000;
      background: rgba(30, 0, 40, 0.84);
      border-radius: 36px;
      padding: 2vw 5vw;
      display: none;
      text-align: center;
      white-space: pre-line;
      font-weight: 900;
      line-height: 1.09;
      pointer-events: none;
      letter-spacing: 0.06em;
      max-width: 98vw;
      word-break: break-word;
      box-shadow: 0 0 32px 12px #24004090;
    }
    .emoji-drop {
      position: fixed; left: 0; pointer-events: none; z-index: 10002;
      font-size: 2.3rem; filter: drop-shadow(0 0 6px #fff) drop-shadow(0 0 10px #f0f);
      user-select: none; will-change: transform;
      animation: emojiFall 2.5s linear forwards;
    }
    @keyframes emojiFall {
      0% { transform: translateY(-15vh) scale(1) rotate(0deg);}
      100% { transform: translateY(110vh) scale(1.13) rotate(360deg);}
    }
    .toast {
      position: fixed;
      bottom: 20px;
      left: 50%;
      transform: translateX(-50%);
      background-color: #333;
      color: #fff;
      padding: 12px 24px;
      border-radius: 25px;
      font-size: 0.95rem;
      z-index: 10005;
      opacity: 0;
      transition: opacity 0.4s ease, bottom 0.4s ease;
      pointer-events: none;
      box-shadow: 0 4px 12px rgba(0,0,0,0.25);
    }
    .toast.show {
      opacity: 1;
      bottom: 40px;
      pointer-events: auto;
    }

    /* Accessibility: Custom Focus Styles */
    button:focus-visible,
    input[type="range"]:focus-visible {
      outline: 3px solid var(--primary-light);
      outline-offset: 2px;
      box-shadow: 0 0 0 5px rgba(166, 77, 166, 0.5); /* Softer glow matching primary-light */
    }
    /* Fallback for browsers not supporting focus-visible, if needed, but modern browsers do well */
    /* button:focus,
    input[type="range"]:focus {
      outline: 2px solid var(--primary-light);
      outline-offset: 1px;
    } */