* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    width: 100%;
    height: 100%;
    background: #000;
    color: #fff;
    overflow: hidden;
    font-family: "Courier New", Courier, monospace;
}

#app {
    position: relative;
    width: 100vw;
    height: 100vh;
}

/* ------- 实验呈现层（黑底白字） ------- */

.stim {
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    font-family: "Courier New", Courier, monospace;
    /* 文档规定 12pt：1pt = 1/72 inch, 96dpi 下 = 16px */
    font-size: 16px;
    font-weight: normal;
    line-height: 1;
    color: #ffffff;
    user-select: none;
    white-space: nowrap;
    display: none;
}

#center { left: 50%; }
#left   { left: calc(50% - var(--ecc-px, 320px)); }
#right  { left: calc(50% + var(--ecc-px, 320px)); }

.stim.show { display: block; }

/* ------- 指导语 / ready? / 反馈 ------- */

.overlay {
    position: absolute;
    inset: 0;
    display: none;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 5vh 8vw;
    font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
}

.overlay.show { display: flex; }

#intro {
    color: #fff;
    font-size: 22px;
    line-height: 2;
}

#intro h2 {
    color: #ff9;
    font-size: 30px;
    margin-bottom: 16px;
}

#intro .hint {
    margin-top: 28px;
    color: #aaa;
    font-size: 18px;
}

#ready {
    color: #ffff00;
    font-family: "Courier New", Courier, monospace;
    font-size: 16px;
}

#feedback {
    font-family: "Microsoft YaHei", sans-serif;
    font-size: 32px;
    font-weight: bold;
}

#feedback.good { color: #5dff5d; }
#feedback.bad  { color: #ff5d5d; }

#uploading {
    color: #ccc;
    font-size: 18px;
    font-family: "Microsoft YaHei", sans-serif;
}

/* ------- 上传失败遮罩 ------- */

#upload-fail {
    color: #fff;
    font-size: 16px;
    line-height: 1.7;
    font-family: "Microsoft YaHei", sans-serif;
}

#upload-fail textarea {
    width: 80vw;
    height: 50vh;
    background: #111;
    color: #ddd;
    border: 1px solid #555;
    padding: 8px;
    margin-top: 12px;
    font-family: "Courier New", monospace;
    font-size: 12px;
}

#upload-fail button {
    margin-top: 12px;
    padding: 8px 18px;
    cursor: pointer;
}