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

body {
    /* min-height 而非固定 height: 内容高于视口时(如手机横屏)可正常滚动, 顶部不会被裁切 */
    min-height: 100vh;
    padding: 16px 0;
    display: flex;
    justify-content: center;
    align-items: center;
    /* 深色底 + 左上/右下两团主题色光晕, 提升质感 (老浏览器回退纯色) */
    background:
        radial-gradient(ellipse 60% 50% at 15% 10%, rgba(37, 99, 235, 0.18), transparent 60%),
        radial-gradient(ellipse 55% 45% at 88% 90%, rgba(14, 165, 233, 0.12), transparent 60%),
        #0b1220;
    font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
    color: #e2e8f0;
    -webkit-tap-highlight-color: transparent;
    -webkit-font-smoothing: antialiased;
}

.login-box {
    width: 420px;
    background: #0f172a;
    border: 1px solid #24314a;
    border-radius: 10px;
    padding: 40px;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.5);
    position: relative;
    overflow: hidden;
}

/* 顶部一条主题色光线, 点缀卡片 */
.login-box::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, transparent, #2563eb, #38bdf8, transparent);
}

.logo {
    text-align: center;
    margin-bottom: 20px;
}

/* 登录页内联 SVG logo: login.html 未加载 app.css, 需在此独立定义尺寸与样式 */
.logo .icon {
    width: 64px;
    height: 64px;
    padding: 14px;
    box-sizing: border-box;
    border-radius: 16px;
    background: linear-gradient(135deg, #2563eb, #1e40af);
    fill: none;
    stroke: #ffffff;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
    box-shadow: 0 4px 16px rgba(37, 99, 235, 0.4);
}

h1 {
    color: #e2e8f0;
    text-align: center;
    font-size: 24px;
    line-height: 1.35;
    max-width: 300px;
    margin: 0 auto 10px;
}

.subtitle {
    text-align: center;
    color: #94a3b8;
    margin-bottom: 30px;
}

input {
    width: 100%;
    height: 45px;
    margin-bottom: 15px;
    border: 1px solid #475569;
    border-radius: 4px;
    padding-left: 15px;
    background: #1e293b;
    color: #e2e8f0;
    font-size: 15px;
    outline: none;
    transition: border-color 0.18s;
}

input::placeholder {
    color: #64748b;
}

input:focus {
    border-color: #3b82f6;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.18);
}

#msg {
    margin-top: 15px;
    text-align: center;
    color: #ef4444;
    font-size: 14px;
    /* 预留高度: 出现/消失提示文字时按钮不跳动 */
    min-height: 20px;
}

/* ================= 移动端适配 (≤480px) ================= */
@media (max-width: 480px) {
    .login-box {
        width: calc(100% - 24px);
        padding: 24px 20px;
    }

    h1 {
        font-size: 19px;
    }
}

/* 手机/平板上 iOS 聚焦输入框时若字号 <16px 会自动放大页面, 提到 16px 规避 */
@media (max-width: 768px) {
    input {
        font-size: 16px;
    }
}

/* ================= 矮屏适配 (手机横屏 / 小窗口, 高度 ≤520px) ================= */
@media (max-height: 520px) {
    body {
        padding: 10px 0;
    }

    .login-box {
        padding: 20px 24px;
    }

    .logo {
        margin-bottom: 12px;
    }

    .logo .icon {
        width: 48px;
        height: 48px;
        padding: 10px;
        border-radius: 12px;
    }

    h1 {
        font-size: 18px;
        margin-bottom: 6px;
    }

    .subtitle {
        margin-bottom: 14px;
        font-size: 13px;
    }

    input {
        height: 40px;
        margin-bottom: 10px;
    }

    .login-box .btn {
        height: 40px;
    }

    #msg {
        margin-top: 8px;
        min-height: 18px;
    }
}