.upload-btn {
    border: 0;
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg: #fff;
    --fg: #17181c;
    --stroke: #86a6f9;
    --success: #25f42f;
}

button {
    font: 1em/1.5 Hind, sans-serif;
}

body {
    background: var(--bg);
    color: var(--fg);
    display: grid;
    place-items: center;
    height: 100vh;
}

.upload-btn {
    --dur: 0.25s;
    background: #fd6566;
    border-radius: 1.25em;
    color: #fff;
    cursor: pointer;
    padding: 0.5em 1em;
    position: relative;
    text-align: center;
    transition: all 0.1s linear;
    width: 6em;
    -webkit-tap-highlight-color: #0000;
    -webkit-appearance: none;
    appearance: none;
    font-size: calc(10px + (40 - 20) * (100vw - 320px) / (1280 - 320));

}

.upload-btn:disabled {
    cursor: not-allowed;
}

.upload-btn:not(:disabled):focus,
.upload-btn:not(:disabled):hover {
    background: rgba(234, 101, 101, 0.65);
}

.upload-btn:focus {
    outline: transparent;
}

.upload-btn-border {
    display: block;
    overflow: visible;
    pointer-events: none;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: auto;
}

.upload-btn-border rect {
    stroke: var(--stroke);
}

.upload-btn-text {
    display: inline-block;
}

.upload-btn-running {
    text-align: right;
}

.upload-btn-running .upload-btn-text {
    animation: flyIn2 var(--dur) ease-in forwards;
}

.upload-btn-done .upload-btn-border {
    animation: sinkInA var(--dur) ease-in forwards;
}

.upload-btn-done .upload-btn-border rect {
    animation: sinkInB var(--dur) ease-in forwards;
}

.upload-btn-done .upload-btn-text {
    animation: pulseIn var(--dur) linear forwards;
    color: var(--success);
}

.upload-btn-ready .upload-btn-text {
    animation: flyIn1 var(--dur) ease-in forwards;
}

/* Dark theme */
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #17181c;
        --fg: #e3e4e8;
    }
}

/* Animations */
@keyframes flyIn1 {
    from {
        opacity: 0;
        transform: translateY(33%);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes flyIn2 {
    from {
        opacity: 0;
        /* (buttonWidth / 2 - rightPadding) + (lastDigit + "%") */
        transform: translate(calc(-2em + 2ch), 33%);
    }
    to {
        opacity: 1;
        transform: translate(calc(-2em + 2ch), 0);
    }
}

@keyframes pulseIn {
    from {
        transform: scale(0);
    }
    33% {
        transform: scale(2.17, 2.17);
    }
    67% {
        transform: scale(1.17, 1.17);
    }
    to {
        transform: scale(1.5);
    }
}

@keyframes sinkInA {
    from {
        transform: scale(1, 1);
    }
    25%, to {
        /* 120/124, 50/54 */
        transform: scale(0.968, 0.925);
    }
}

@keyframes sinkInB {
    from {
        stroke-width: 4;
    }
    25%, to {
        stroke-width: 0;
    }
}

.drag-drop-area {
    border: 2px dashed #ccc;
    border-radius: 5px;
    padding: 20px;
    text-align: center;
    cursor: pointer;
}

.drag-drop-area:hover {
    background-color: #f0f0f0;
}

/* 定义扁平风格的文件输入框样式 */
.flat-file-input {
    border: none;
    border-bottom: 2px solid #ff6666; /* 淡红色 */
    outline: none;
    padding: 8px 12px;
    font-size: 16px;
    background-color: transparent; /* 透明背景 */
    transition: border-bottom-color 0.3s; /* 添加过渡效果 */
    width: 200px; /* 输入框宽度 */
    cursor: pointer; /* 鼠标样式为手型 */
}

/* 悬停时底部边框颜色变化 */
.flat-file-input:hover {
    border-bottom-color: #ffcccc; /* 底部边框，淡红色 */
}

/* 获得焦点时底部边框颜色变化 */
.flat-file-input:focus {
    border-bottom-color: #ff6666; /* 更深的红色 */
}

/* 隐藏默认的文件选择按钮 */
.flat-file-input::-webkit-file-upload-button {
    display: none;
}

/* 自定义文件选择按钮样式 */
.custom-file-select-btn {
    border: none;
    background-color: #ff6666; /* 按钮底色为淡红色 */
    color: #fff; /* 文字颜色为白色 */
    padding: 8px 12px;
    font-size: 16px;
    cursor: pointer; /* 鼠标样式为手型 */
    transition: background-color 0.3s; /* 添加过渡效果 */
}

/* 悬停时按钮背景颜色变化 */
.custom-file-select-btn:hover {
    background-color: #ff9999; /* 淡红色 */
}

/* 点击时按钮背景颜色变化 */
.custom-file-select-btn:active {
    background-color: #ff6666; /* 更深的红色 */
}