@font-face {
    font-family: 'AppFont';
    src: url('../fonts/AppFont.ttf') format('truetype');
    font-weight: normal;
    font-style: normal;
  }
  * { margin: 0; padding: 0; box-sizing: border-box; }
  html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
  }

  body {
    background: #0a0a1a;
    color: #fff;
    font-family: 'AppFont', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    user-select: none;
  }

  #load-screen {
    position: fixed; inset: 0;
    display: flex; flex-direction: column;
    align-items: center; justify-content: center;
    background: #000;
    z-index: 1000;
    transition: opacity 0.6s ease;
    padding: 20px;
  }
  #load-screen.hidden { opacity: 0; pointer-events: none; }

  /* Main screen background layer: cross-fades to the chart background once loading finishes; sits below the main screen content */
  #load-bg {
    position: absolute; inset: 0;
    z-index: 0;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
  }
  #load-screen > .logo-svg,
  #load-screen > .home-welcome,
  #load-screen > p,
  #load-screen > .file-row {
    position: relative;
    z-index: 1;
  }
  #load-screen > #settings-toggle { z-index: 2; }
  #load-toast {
    position: absolute;
    top: clamp(18px, 3.5vh, 34px);
    left: clamp(18px, 3.5vw, 42px);
    z-index: 5;
    max-width: min(54vw, 460px);
    padding: 12px 18px;
    overflow: hidden;
    color: #fff;
    background: #1d1d1d;
    border-left: 3px solid var(--md-primary);
    border-radius: 0 12px 12px 0;
    box-shadow: 0 8px 24px rgba(0,0,0,.35);
    font-size: clamp(12px, 1.6vmin, 15px);
    line-height: 1.35;
    text-overflow: ellipsis;
    white-space: nowrap;
    opacity: 0;
    transform: translateX(calc(-100% - 48px));
    pointer-events: none;
  }
  #load-toast.show { animation: load-toast-in 3.6s linear both; }
  @keyframes load-toast-in {
    0% { opacity: 0; transform: translateX(calc(-100% - 48px)); animation-timing-function: cubic-bezier(.2,.8,.2,1); }
    12% { opacity: 1; transform: translateX(0); animation-timing-function: linear; }
    78% { opacity: 1; transform: translateX(0); animation-timing-function: cubic-bezier(.32,0,.67,0); }
    100% { opacity: 0; transform: translateX(calc(-100% - 48px)); }
  }
#load-screen.loading-mode { z-index: 1000001; opacity: 0; transition: opacity 0.5s ease; }
#load-screen.loading-mode > *:not(#loading-indicator) { display: none !important; }
#loading-indicator { display: none; position: absolute; inset: 0; z-index: 1; }
#load-screen.loading-mode #loading-indicator { display: block; }
#load-screen.loading-mode { background: transparent; }
#ld-img-bar { position: absolute; top: 0; left: 0; width: 100%; height: 100%; z-index: 0; pointer-events: none; }
#ld-img-bar img { width: 100%; height: 100%; object-fit: contain; display: block; }
#ld-img-panel { position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%); width: min(100vw, 177.78vh); aspect-ratio: 2560 / 1440; z-index: 1; pointer-events: none; -webkit-mask-image: url('../assets/mask-track.png'); -webkit-mask-size: 100% 100%; mask-image: url('../assets/mask-track.png'); mask-size: 100% 100%; }
  #ld-illus { position: absolute; left: calc(1124 / 2560 * 100%); top: calc(292 / 1440 * 100%); width: calc(1284 / 2560 * 100%); height: calc(686 / 1440 * 100%); object-fit: cover; display: block; z-index: 2; }
  /* Loading page Tip: positioned after the bottom text object of tip/1.png (134,1314)-(716,1362), replaced with the actual text */
  #ld-tip {
    position: absolute;
    left: calc(134 / 2560 * 100%);
    top: calc(1314 / 1440 * 100%);
    width: calc(582 / 2560 * 100%);
    height: calc(49 / 1440 * 100%);
    display: flex; align-items: center; justify-content: flex-start;
    text-align: left;
    white-space: nowrap;
    overflow: visible;
    color: #fff;
    font-size: min(1.5vw, 2.6vh);
    line-height: 1.2;
    z-index: 3;
    pointer-events: auto;
    cursor: pointer;
    font-family: 'AppFont', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  }
  /* Loading page song title: positioned after the 3.png object (256,523)-(417,579); kept outside #ld-img-panel so its mask cannot clip it, coordinates converted to the viewport */
  #ld-songname {
    position: absolute;
    left: calc(50% + (256 / 2560 - 0.5) * min(100vw, 177.78vh));
    top: calc(50% + (523 / 1440 - 0.5) * min(100vw, 177.78vh) * 0.5625);
    width: auto;
    min-width: 0;
    max-width: calc(min(100vw, 177.78vh) * 0.6);
    height: calc((57 / 1440) * min(100vw, 177.78vh) * 0.5625);
    display: flex; align-items: center;
    justify-content: flex-start;
    text-align: left;
    white-space: nowrap;
    color: #fff;
    font-size: calc((52 / 1440) * min(100vw, 177.78vh) * 0.5625);
    line-height: 1.2;
    overflow: hidden;
    text-overflow: ellipsis;
    z-index: 4;
    pointer-events: none;
    font-family: 'AppFont', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  }
  #ld-composer {
    position: absolute;
    left: calc(50% + (253.56454 / 2560 - 0.5) * min(100vw, 177.78vh));
    top: calc(50% + (608 / 1440 - 0.5) * min(100vw, 177.78vh) * 0.5625);
    width: auto;
    min-width: 0;
    max-width: calc(min(100vw, 177.78vh) * 0.6);
    height: calc((34 / 1440) * min(100vw, 177.78vh) * 0.5625);
    display: flex; align-items: center;
    justify-content: flex-start;
    text-align: left;
    white-space: nowrap;
    color: #fff;
    font-size: calc((33 / 1440) * min(100vw, 177.78vh) * 0.5625);
    line-height: 1.2;
    overflow: hidden;
    text-overflow: ellipsis;
    z-index: 4;
    pointer-events: none;
font-family: 'AppFont', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  }
  @keyframes spin { to { transform: rotate(360deg); } }
  .logo-svg {
    width: 80%;
    max-width: 600px;
    margin-bottom: 24px;
  }
  .logo-svg svg {
    width: 100%;
    height: auto;
    display: block;
  }

  #load-screen p {
    color: #889;
    margin-bottom: 28px;
    font-size: 14px;
    text-align: center;
  }

  .file-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 16px;
  }

  .standalone-chk {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 16px;
    border: 1px dashed rgba(255, 255, 255, 0.45);
    border-radius: 10px;
    color: #e8e8e8;
    font-size: 13px;
    cursor: pointer;
    user-select: none;
    background: rgba(255, 255, 255, 0.06);
  }
  .standalone-chk:hover { background: rgba(255, 255, 255, 0.12); }
  .standalone-chk input { width: 15px; height: 15px; accent-color: #4cc2ff; cursor: pointer; }

  .btn {
    padding: 12px 28px;
    border: none;
    border-radius: 10px;
    color: #fff;
    cursor: pointer;
    font-size: 15px;
    transition: background 0.25s;
    display: inline-flex;
    align-items: center;
    gap: 8px;
  }
  #settings-toggle svg {
    width: 26px;
    height: 26px;
  }

  .btn svg {
    width: 18px;
    height: 18px;
    flex: none;
  }
  .settings-panel h2 svg,
  .settings-panel h3 svg {
    width: 18px;
    height: 18px;
    vertical-align: -3px;
    margin-right: 6px;
  }
  .btn.primary { background: #fff; color: #000; }
  .btn.primary:hover { background: #ccc; }
  .btn.blue { background: #fff; color: #000; }
  .btn.blue:hover { background: #ddd; }
  .btn.cyan { background: #fff; color: #000; border: 1px solid #fff; }
  .btn.cyan:hover { background: #ddd; }
  .btn.green { background: #fff; color: #000; }
  .btn.green:hover { background: #ddd; }

  #settings-toggle {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 500;
    background: rgba(255,255,255,0.1);
    border: none;
    border-radius: 50%;
    width: 48px;
    height: 48px;
    font-size: 24px;
    color: #ccc;
    cursor: pointer;
    transition: background 0.2s, transform 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
  }
  #settings-toggle:hover {
    background: rgba(255,255,255,0.25);
    transform: rotate(60deg);
  }

  #settings-modal {
    position: fixed;
    inset: 0;
    z-index: 2000;
    background: rgba(0,0,0,0.7);
    display: none;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
  }
  #settings-modal.open { display: flex; }
  .settings-panel {
    background: #0b0b0b;
    border-radius: 0;
    padding: 30px 35px;
    max-width: 520px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 8px 40px rgba(0,0,0,0.8);
    color: #eee;
    border: 1px solid #2a2a2a;
  }
  .settings-panel h2 {
    font-size: 22px;
    margin-bottom: 20px;
    color: #fff;
    letter-spacing: 1px;
    border-bottom: 1px solid #2a2a2a;
    padding-bottom: 10px;
  }
  .settings-group {
    margin-bottom: 22px;
  }
  .settings-group h3 {
    font-size: 16px;
    color: #aaa;
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
  }
  .setting-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
    font-size: 14px;
  }
  .setting-item label {
    flex: 1;
    color: #ccc;
  }
  .setting-item input[type="range"] {
    width: 140px;
    accent-color: #fff;
    cursor: pointer;
    background: transparent;
  }
  .setting-item .val {
    min-width: 32px;
    text-align: center;
    color: #fff;
  }
  .setting-item input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: #fff;
    cursor: pointer;
  }
  .settings-close {
    text-align: right;
    margin-top: 10px;
  }
  .settings-close button {
    background: #fff;
    border: none;
    padding: 8px 24px;
    border-radius: 0;
    color: #000;
    font-size: 14px;
    cursor: pointer;
    transition: background 0.2s;
  }
  .settings-close button:hover { background: #ccc; }

  #file-input, #rp-input { display: none; }

  #game-canvas {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    z-index: 1;
    display: block;
    touch-action: none;
  }

  #fx-canvas {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    z-index: 2;
    display: none;
    pointer-events: none;
  }

  #pause-btn {
    position: fixed;
    top: calc(26px * var(--uis, 1)); left: calc(20px * var(--uis, 1));
    z-index: 200;
    color: #fff;
    cursor: pointer;
    background: transparent !important;
    border: none !important;
    padding: 0;
    outline: none;
    pointer-events: auto;
    transform-origin: center;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  #pause-btn:hover { color: #fff; }
  #pause-btn svg { display: block; width: calc(30px * var(--uis, 1)); height: calc(30px * var(--uis, 1)); }
#pause-btn svg path[fill="#FFFFFF"] { fill: currentColor; }
  #pause-btn .icon-play { display: none; }
  #pause-btn.paused .icon-pause { display: none; }
  #pause-btn.paused .icon-play { display: block; }

  #combo-area {
    position: fixed;
    top: calc(6px * var(--uis, 1));
    left: 50%;
    transform: translateX(-50%);
    z-index: 200;
    text-align: center;
    display: none;
    pointer-events: none;
  }
  #combo-number {
    font-size: calc(54px * var(--uis, 1));
    color: #fff;
    line-height: 1;
    transform-origin: center;
  }
  #combo-label {
    font-size: calc(18px * 0.965 * var(--uis, 1));
    letter-spacing: 0.015em;
    color: #E7E7E7;
    margin-top: calc(-6px * var(--uis, 1));
    transform-origin: center;
  }

  #score-display {
    position: fixed;
    top: calc(20px * var(--uis, 1)); right: calc(24px * var(--uis, 1));
    z-index: 200;
    font-size: calc(36px * var(--uis, 1));
    line-height: calc(36px * var(--uis, 1));
    color: #fff;
    font-variant-numeric: tabular-nums;
    letter-spacing: calc(1px * var(--uis, 1));
    pointer-events: none;
    transform-origin: center;
  }

  #title-display {
    position: fixed;
    bottom: calc(18px * var(--uis, 1)); left: calc(30px * var(--uis, 1));
    z-index: 200;
    font-size: calc(24px * var(--uis, 1));
    color: #fff;
    max-width: 40vw;
    white-space: nowrap;
    overflow: visible;
    overflow: hidden;
    text-overflow: ellipsis;
    pointer-events: none;
    transform-origin: center;
  }

  #difficulty-display {
    position: fixed;
    bottom: calc(18px * var(--uis, 1)); right: calc(30px * var(--uis, 1));
    z-index: 200;
    font-size: calc(22px * var(--uis, 1));
    color: #fff;
    pointer-events: none;
    transform-origin: center;
  }

  .lyric-slot {
    position: fixed;
    left: 50%;
    bottom: 9vh;
    transform: translateX(-50%);
    z-index: 150;
    font-size: calc(26px * var(--uis, 1));
    color: #fff;
    letter-spacing: calc(30px * var(--uis, 1));
    white-space: nowrap;
    max-width: 86vw;
    overflow: hidden;
    text-overflow: ellipsis;
    opacity: 0;
    pointer-events: none;
    transition: opacity 1s cubic-bezier(0.16, 1, 0.3, 1), letter-spacing 1s cubic-bezier(0.16, 1, 0.3, 1);
    will-change: letter-spacing, opacity;
  }
  .lyric-slot.lyric-in {
    opacity: 1;
    letter-spacing: calc(2px * var(--uis, 1));
  }
  .lyric-slot.lyric-out {
    opacity: 0;
    letter-spacing: calc(2px * var(--uis, 1));
    transform: translateX(-50%) translateY(-48px);
    transition: opacity 1s cubic-bezier(0.32, 0, 0.67, 0), letter-spacing 1s cubic-bezier(0.32, 0, 0.67, 0), transform 1s cubic-bezier(0.32, 0, 0.67, 0);
  }
  .lyric-char {
    opacity: 0.3;
    transition: opacity 0.15s linear;
  }
  .lyric-char.on {
    opacity: 1;
  }

  #ui-bar {
    position: fixed;
    display: block;
    left: 0;
    right: 0;
    top: 0;
    height: calc(8px * var(--uis, 1));
    background: transparent;
    overflow: visible;
    pointer-events: none;
    z-index: 201;
    opacity: 0.8;
    transform-origin: left;
  }
  #ui-bar-fill {
    height: 100%;
    width: 0%;
    background: rgba(255, 255, 255, 0.5);
    transition: width 0.1s linear;
    position: relative;
  }
  #ui-bar-head {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%) scaleX(0.25);
    transform-origin: right center;
    width: calc(8px * var(--uis, 1));
    height: calc(8px * var(--uis, 1));
    background: white;
    pointer-events: none;
    box-shadow: 0 0 10px rgba(255,255,255,0.8);
    transition: opacity 1s easeInCirc;
  }

  #status-msg {
    position: fixed;
    bottom: 60px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 300;
    background: rgba(0,0,0,0.7);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    color: #aaf;
    pointer-events: none;
    transition: opacity 0.3s;
    opacity: 0;
  }
  #status-msg.show { opacity: 1; }

  #unlock-overlay {
    position: fixed;
    inset: 0;
    z-index: 1100;
    background: #000;
    overflow: hidden;
  }
  #unlock-overlay.hidden { display: none; }
  #unlock-video {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: #000;
    display: block;
  }

  @media (max-width: 600px) {
    #load-screen { justify-content: center; }
    #load-screen > .home-welcome { width: min(86vw, 560px); margin-bottom: 5vh; }
    #load-screen > .file-row:not(#chart-action-row) { width: min(86vw, 420px); grid-template-columns: 1fr; }
    #load-screen > #chart-action-row { width: min(86vw, 420px); }
    #load-screen .btn { min-height: 46px; font-size: clamp(12px, 3.3vw, 14px); }
    #settings-toggle { right: 5vw; bottom: 5vw; width: 48px; height: 48px; }
    .settings-panel { width: calc(100vw - 8vw); max-height: calc(100svh - 8vw); padding: 20px; border-radius: 20px; }
    .setting-item input[type="range"] { width: 100px; }
  }
  @media (min-width: 601px) and (max-height: 620px) {
    #load-screen > .home-welcome { margin-bottom: 2.5vh; }
    #load-screen > .file-row { margin-bottom: 1vh; }
    #load-screen .btn { min-height: 42px; }
  }
  @media (max-width: 360px) {
    #load-screen > .file-row:not(#chart-action-row),
    #load-screen > #chart-action-row { width: 90vw; }
    .home-welcome h1 { font-size: 34px; }
    .settings-panel { padding: 16px; }
    .setting-item label { font-size: 12px; }
  }

/* Opening overlay: blurred chart background + 50% black, expands from the left as a polygon (-15deg slanted edge, easeOutExpo 1s), covering every UI element of the main page
   uses a clip-path polygon instead of scaleX so the image is not squashed; the anchor is on the left, expanding from zero width to full screen */
#intro-overlay {
  position: fixed; inset: 0;
  z-index: 999999;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  pointer-events: none;
  visibility: hidden;
  clip-path: polygon(0 0, 0 0, 0 100%, 0 100%);
  transition: none;
}
#intro-overlay::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.8);
  transition: background-color 0.5s cubic-bezier(0.55, 0.06, 0.68, 0.19);
}
#intro-overlay.bright::after { background: transparent; }

/* Pause overlay: the global blur and the icons fade in together (easeOutExpo .5s) */
#pause-overlay {
  position: fixed; inset: 0; z-index: 10000;
  display: flex; align-items: center; justify-content: center;
  background: rgba(8, 8, 24, 0.42);
  opacity: 0; pointer-events: none;
  backdrop-filter: blur(0px);
  transition: opacity .5s cubic-bezier(.19,1,.22,1), backdrop-filter .5s cubic-bezier(.19,1,.22,1);
}
#pause-overlay.show {
  opacity: 1; pointer-events: auto;
  backdrop-filter: blur(14px) saturate(1.1);
}
.pause-menu { display: flex; gap: clamp(40px, 11vmin, 120px); align-items: center; }
.pause-act {
  background: none; border: none; padding: 0;
  color: #fff; cursor: pointer; opacity: 0;
  transition: opacity .5s cubic-bezier(.19,1,.22,1);
}
#pause-overlay.show .pause-act { opacity: 1; }
.pause-act svg { width: clamp(40px, 8vmin, 80px); height: clamp(40px, 8vmin, 80px); fill: #fff; display: block; }
#countdown-a, #countdown-b {
  position: fixed; top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  font-size: clamp(48px, 12vmin, 120px); color: #fff;
  opacity: 0; z-index: 10001; pointer-events: none;
  transition: none;
}
@media (max-width: 640px) {
  .pause-menu { gap: clamp(24px, 8vmin, 48px); }
  .pause-act svg { width: clamp(32px, 8vmin, 48px); height: clamp(32px, 8vmin, 48px); }
}

  /* Splash animation: a full-black mask plus the opening logo, which fades in, pauses, then fades out */
  body { background: #000; }
  #splash-overlay {
    position: fixed; inset: 0;
    background: #000;
    display: flex; align-items: center; justify-content: center;
    z-index: 1000010;
    pointer-events: none;
    transition: opacity 0.8s ease;
  }
  #splash-overlay.splash-done { opacity: 0; }
  #splash-svg { width: min(60vw, calc(60vh * 3391 / 628)); height: auto; display: block; }

/* Material-style home surface. These rules intentionally stay scoped to the
   import screen and settings dialog so the in-game HUD keeps its timing and look. */
  :root {
    --md-primary: #ff6d00;
    --md-primary-dark: #d95700;
    --md-on-primary: #241000;
    --md-surface: #f7f8fc;
    --md-surface-container: rgba(255,255,255,.82);
    --md-surface-high: rgba(255,255,255,.94);
    --md-on-surface: #202124;
    --md-on-surface-variant: #62656d;
    --md-outline: #c6c8cf;
    --md-shadow: 0 18px 48px rgba(28, 31, 39, .16), 0 3px 10px rgba(28, 31, 39, .08);
  }

  #load-screen {
    align-items: center;
    justify-content: center;
    gap: 0;
    overflow: hidden;
    color: #f5f5f5;
    background: #000;
  }
  #load-screen::before, #load-screen::after { display: none; }
  #load-screen > .home-welcome,
  #load-screen > p,
  #load-screen > .file-row,
  #load-screen > #settings-toggle { opacity: 0; transform: translateY(20px); }
  #load-screen > .home-welcome { width: min(68vw, 680px); margin: 0 0 clamp(20px, 4vh, 34px); text-align: center; }
  .home-welcome span { display: block; margin-bottom: clamp(8px, 1.4vh, 14px); color: #ff8a3d; font-size: clamp(10px, 1.35vmin, 13px); font-weight: 700; letter-spacing: .2em; }
  .home-welcome h1 { color: #fff; font-size: clamp(34px, 7.2vmin, 68px); font-weight: 600; line-height: 1.05; letter-spacing: .02em; }
  .home-welcome p { margin: clamp(10px, 1.8vh, 16px) 0 0 !important; color: #9b9b9b !important; font-size: clamp(12px, 1.7vmin, 15px) !important; }
  #load-screen > .file-row { position: relative; z-index: 1; gap: clamp(8px, 1.2vw, 14px); width: min(76vw, 760px); margin: 0 auto clamp(10px, 1.8vh, 16px); padding: 0; border: 0; border-radius: 0; background: transparent; box-shadow: none; }
  #load-screen > .file-row:not(#chart-action-row) { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); }
  #load-screen > .file-row .btn { width: 100%; justify-content: center; }
  #load-screen > #chart-action-row { width: auto; padding: 0; border: 0; background: transparent; box-shadow: none; }
  #load-screen > #settings-toggle { animation-delay: .3s; }
  #load-screen > .home-welcome, #load-screen > .file-row { opacity: 0; transform: translateY(20px); }
  body.splash-finished #load-screen > .home-welcome { animation: md-home-enter .7s cubic-bezier(.2,.8,.2,1) .08s both; }
  body.splash-finished #load-screen > .file-row { animation: md-home-enter .7s cubic-bezier(.2,.8,.2,1) .2s both; }
  body.splash-finished #load-screen > #chart-action-row { animation-delay: .28s; }
  body.splash-finished #load-screen > #settings-toggle { animation: md-home-enter .7s cubic-bezier(.2,.8,.2,1) .3s both; }
  @keyframes md-home-enter { from { opacity: 0; transform: translateY(18px) scale(.98); } to { opacity: 1; transform: translateY(0) scale(1); } }

  #load-screen .btn,
  #settings-modal button {
    position: relative;
    overflow: hidden;
    min-height: clamp(42px, 6.2vmin, 52px);
    padding: 0 clamp(12px, 1.8vw, 22px);
    border-radius: 14px;
    border: 0;
    font: 600 14px 'AppFont', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    letter-spacing: .01em;
    transition: transform .2s cubic-bezier(.2,.8,.2,1), box-shadow .2s ease, background-color .2s ease, border-color .2s ease, color .2s ease;
  }
  #load-screen .btn:hover,
  #settings-modal button:hover { transform: none; box-shadow: 0 8px 18px rgba(31, 35, 45, .14); }
  #load-screen .btn:active,
  #settings-modal button:active { transform: translateY(0) scale(.98); box-shadow: none; }
  #load-screen .btn.primary { background: var(--md-primary); color: var(--md-on-primary); box-shadow: 0 4px 10px rgba(255, 109, 0, .26); }
  #load-screen .btn.primary:hover { background: #ff8126; }
  #load-screen .btn.blue,
  #load-screen .btn.green { background: #1e1e1e; color: #f1f1f1; border-color: transparent; box-shadow: none; }
  #load-screen .btn.blue:hover,
  #load-screen .btn.green:hover { background: #2b2b2b; border-color: transparent; }
  #load-screen .btn.gray { background: transparent; color: #bdbdbd; border-color: transparent; }
  #load-screen .btn.gray:hover { background: #1d1d1d; }
  #load-screen .btn svg { color: currentColor; transition: transform .2s ease; }
  #load-screen .btn:hover svg { transform: scale(1.08); }
  #load-screen .btn.primary svg { color: var(--md-on-primary); }
  #settings-toggle {
    right: 28px; bottom: 28px; width: 52px; height: 52px;
    color: #f0f0f0; background: #171717;
    border: 1px solid #3b3b3b; border-radius: 16px;
    box-shadow: 0 5px 16px rgba(0,0,0,.4);
    backdrop-filter: blur(14px);
    transition: transform .25s cubic-bezier(.2,.8,.2,1), background-color .2s ease, box-shadow .2s ease;
  }
  #settings-toggle:hover { background: #252525; transform: none; box-shadow: 0 10px 24px rgba(0,0,0,.55); }
  #settings-toggle:active { transform: scale(.94); }
  #settings-toggle svg { width: 23px; height: 23px; transition: transform .45s cubic-bezier(.2,.8,.2,1); }
  #settings-toggle:hover svg { transform: rotate(60deg); }

  #settings-modal {
    display: flex;
    visibility: hidden;
    opacity: 0;
    pointer-events: none;
    background: rgba(24, 27, 34, .38);
    backdrop-filter: blur(10px) saturate(1.05);
    transition: opacity .28s ease, visibility 0s linear .28s;
  }
  #settings-modal.open { display: flex; visibility: visible; opacity: 1; pointer-events: auto; transition-delay: 0s; }
  .settings-panel {
    width: min(600px, calc(100vw - 6vw));
    max-height: min(820px, calc(100svh - 6vw));
    padding: clamp(20px, 3.2vw, 30px) clamp(18px, 3.2vw, 30px) clamp(16px, 2.5vw, 22px);
    overflow-y: auto;
    color: var(--md-on-surface);
    background: var(--md-surface-high);
    border: 1px solid rgba(255,255,255,.75);
    border-radius: 24px;
    box-shadow: var(--md-shadow);
    transform: translateY(22px) scale(.96);
    transition: transform .34s cubic-bezier(.2,.8,.2,1);
    scrollbar-width: thin;
    scrollbar-color: var(--md-primary) transparent;
  }
  #settings-modal.open .settings-panel { transform: translateY(0) scale(1); }
  #settings-modal .settings-panel::-webkit-scrollbar { width: 8px; }
  #settings-modal .settings-panel::-webkit-scrollbar-track { margin: 16px 0; background: transparent; }
  #settings-modal .settings-panel::-webkit-scrollbar-thumb {
    min-height: 42px;
    border: 2px solid transparent;
    border-radius: 999px;
    background: var(--md-primary);
    background-clip: padding-box;
    transition: background-color .2s ease;
  }
  #settings-modal .settings-panel::-webkit-scrollbar-thumb:hover { background-color: var(--md-primary-dark); }
  .settings-panel h2 { margin-bottom: 22px; padding-bottom: 16px; color: var(--md-on-surface); border-bottom: 1px solid #e1e3e8; font-size: 22px; letter-spacing: .01em; }
  .settings-panel h2 svg, .settings-panel h3 svg { color: var(--md-primary); }
  .settings-group { margin: 0 0 18px; padding: 16px 18px 8px; border: 1px solid #e1e3e8; border-radius: 18px; background: rgba(255,255,255,.58); }
  .settings-group h3 { margin-bottom: 14px; color: var(--md-on-surface); font-size: 13px; letter-spacing: .08em; }
  .setting-item { min-height: 38px; margin-bottom: 8px; color: var(--md-on-surface-variant); }
  .setting-item label { color: var(--md-on-surface-variant); font-size: 13px; }
  .setting-item .val { color: var(--md-primary-dark); font-weight: 700; }
  .setting-item input[type="range"] { accent-color: var(--md-primary); }
  .setting-item input[type="checkbox"] { width: 20px; height: 20px; accent-color: var(--md-primary); }
  .settings-close { margin-top: 8px; }
  .settings-close button { min-width: 96px; background: var(--md-primary); color: var(--md-on-primary); box-shadow: 0 4px 10px rgba(255,109,0,.22); }

  /* Material range slider and switch controls for the settings surface. */
  #settings-modal .setting-item input[type="range"] {
    width: 156px;
    height: 20px;
    margin: 0 8px;
    appearance: none;
    -webkit-appearance: none;
    cursor: pointer;
    background: transparent;
  }
  #settings-modal .setting-item input[type="range"]::-webkit-slider-runnable-track {
    height: 4px;
    border-radius: 4px;
    background: #d7d9df;
  }
  #settings-modal .setting-item input[type="range"]::-webkit-slider-thumb {
    width: 18px;
    height: 18px;
    margin-top: -7px;
    appearance: none;
    -webkit-appearance: none;
    border: 0;
    border-radius: 50%;
    background: var(--md-primary);
    box-shadow: 0 1px 4px rgba(28,31,39,.28);
    transition: transform .18s ease, box-shadow .18s ease;
  }
  #settings-modal .setting-item input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.16);
    box-shadow: 0 0 0 8px rgba(255,109,0,.14), 0 1px 4px rgba(28,31,39,.28);
  }
  #settings-modal .setting-item input[type="range"]::-moz-range-track {
    height: 4px;
    border-radius: 4px;
    background: #d7d9df;
  }
  #settings-modal .setting-item input[type="range"]::-moz-range-progress {
    height: 4px;
    border-radius: 4px;
    background: var(--md-primary);
  }
  #settings-modal .setting-item input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border: 0;
    border-radius: 50%;
    background: var(--md-primary);
    box-shadow: 0 1px 4px rgba(28,31,39,.28);
  }
  #settings-modal .setting-item input[type="checkbox"] {
    position: relative;
    width: 38px;
    height: 22px;
    margin: 0 2px;
    appearance: none;
    -webkit-appearance: none;
    flex: 0 0 38px;
    border: 2px solid #7a7d86;
    border-radius: 999px;
    background: #e2e3e8;
    cursor: pointer;
    transition: background-color .2s ease, border-color .2s ease, box-shadow .2s ease;
  }
  #settings-modal .setting-item input[type="checkbox"]::after {
    content: '';
    position: absolute;
    left: 2px;
    top: 2px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: #fff;
    box-shadow: 0 1px 3px rgba(28,31,39,.3);
    transition: transform .2s cubic-bezier(.2,.8,.2,1), width .2s ease, height .2s ease, top .2s ease;
  }
  #settings-modal .setting-item input[type="checkbox"]:checked {
    border-color: var(--md-primary);
    background: var(--md-primary);
    box-shadow: 0 0 0 4px rgba(255,109,0,.12);
  }
  #settings-modal .setting-item input[type="checkbox"]:checked::after {
    transform: translateX(16px);
  }
  #settings-modal .setting-item input[type="checkbox"]:focus-visible,
  #settings-modal .setting-item input[type="range"]:focus-visible {
    outline: 3px solid rgba(255,109,0,.26);
    outline-offset: 3px;
  }

  .md-ripple { position: absolute; border-radius: 50%; pointer-events: none; background: currentColor; opacity: .18; transform: scale(0); animation: md-ripple .55s ease-out; }
  @keyframes md-ripple { to { opacity: 0; transform: scale(3.5); } }
  @media (prefers-reduced-motion: reduce) {
    #load-screen > .logo-svg, #load-screen > .home-welcome, #load-screen > p, #load-screen > .file-row, #load-screen > #settings-toggle { animation: none; opacity: 1; transform: none; }
    #load-screen .btn, #settings-modal button, #settings-modal, .settings-panel { transition-duration: .01ms; }
  }