:root {
    --bg: #f4f6fb;
    --bg-accent: #e8edf9;
    --card: #ffffff;
    --text: #1c2333;
    --text-dim: #6b7385;
    --border: #e2e6f0;
    --primary: #3355ff;
    --primary-hover: #2743d6;
    --primary-fg: #ffffff;
    --ok-bg: #e7f7ee;
    --ok-fg: #11733f;
    --err-fg: #c0303b;
    --code-bg: #f7f8fc;
    --shadow: 0 8px 30px rgba(24, 39, 75, 0.08);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #12141c;
        --bg-accent: #171a25;
        --card: #1b1e2a;
        --text: #e9ecf5;
        --text-dim: #949cb4;
        --border: #2a2f41;
        --primary: #5b78ff;
        --primary-hover: #6d87ff;
        --primary-fg: #ffffff;
        --ok-bg: #14301f;
        --ok-fg: #55d38c;
        --err-fg: #ff7a86;
        --code-bg: #14171f;
        --shadow: 0 10px 34px rgba(0, 0, 0, 0.45);
    }
}

* { box-sizing: border-box; }

html, body {
    margin: 0;
    padding: 0;
    min-height: 100%;
}

body {
    background:
        radial-gradient(900px 420px at 12% -10%, var(--bg-accent), transparent 60%),
        var(--bg);
    color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
    font-size: 15px;
    line-height: 1.6;
    display: flex;
    justify-content: center;
    padding: 48px 20px 64px;
}

.shell { width: 100%; max-width: 620px; }
.shell-narrow { max-width: 420px; }

/* 头部 ------------------------------------------------------------------ */
.brand {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 22px;
}

.logo {
    width: 46px;
    height: 46px;
    flex: 0 0 46px;
    border-radius: 13px;
    background: linear-gradient(135deg, var(--primary), #8a6dff);
    color: #fff;
    font-weight: 800;
    letter-spacing: .5px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    box-shadow: var(--shadow);
}

.brand h1 { margin: 0; font-size: 19px; font-weight: 700; letter-spacing: .2px; }
.brand .sub { margin: 2px 0 0; color: var(--text-dim); font-size: 13px; }

/* 卡片 ------------------------------------------------------------------ */
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 22px;
    box-shadow: var(--shadow);
    margin-bottom: 16px;
}

.card-title { margin: 0 0 4px; font-size: 16px; }

/* 页签 ------------------------------------------------------------------ */
.tabs {
    display: flex;
    align-items: center;
    gap: 6px;
    margin: -4px -4px 18px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 12px;
}

.tabs .spacer { flex: 1; }

.who { font-size: 12.5px; color: var(--text-dim); }

.tab {
    appearance: none;
    border: 1px solid transparent;
    background: transparent;
    color: var(--text-dim);
    font-size: 14px;
    font-weight: 600;
    padding: 7px 14px;
    border-radius: 9px;
    cursor: pointer;
    font-family: inherit;
}

.tab:hover { color: var(--text); background: var(--bg-accent); }

.tab.active {
    color: var(--primary);
    background: color-mix(in srgb, var(--primary) 12%, transparent);
    border-color: color-mix(in srgb, var(--primary) 26%, transparent);
}

.link {
    appearance: none;
    border: 0;
    background: transparent;
    color: var(--text-dim);
    font-size: 13px;
    cursor: pointer;
    font-family: inherit;
    text-decoration: underline;
    padding: 4px;
}

.link:hover { color: var(--text); }

/* 表单 ------------------------------------------------------------------ */
.field { margin-bottom: 16px; }

.field label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--text);
}

.field .opt { color: var(--text-dim); font-weight: 400; }

input[type="text"],
input[type="password"],
textarea {
    width: 100%;
    padding: 11px 13px;
    border: 1px solid var(--border);
    border-radius: 10px;
    background: var(--code-bg);
    color: var(--text);
    font-size: 15px;
    font-family: inherit;
    outline: none;
    transition: border-color .15s, box-shadow .15s;
}

input:focus, textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px color-mix(in srgb, var(--primary) 18%, transparent);
}

input::placeholder, textarea::placeholder { color: var(--text-dim); opacity: .75; }

#machineCode, #vMachine {
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Cascadia Mono", monospace;
    letter-spacing: 2px;
    font-size: 17px;
    text-align: center;
    text-transform: uppercase;
}

/* 动态验证码输入框：等宽、居中、大字距，方便核对 */
input.otp {
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Cascadia Mono", monospace;
    font-size: 24px;
    letter-spacing: 8px;
    text-align: center;
    text-indent: 8px;
    padding: 12px 13px;
}

#mfaCard .hint { margin-bottom: 16px; }
#mfaCard .btn + .btn { margin-top: 10px; }

textarea {
    resize: vertical;
    line-height: 1.5;
}

.code {
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Cascadia Mono", monospace;
    font-size: 12.5px;
    letter-spacing: .2px;
    word-break: break-all;
    text-align: left !important;
}

/* 按钮 ------------------------------------------------------------------ */
.btn {
    appearance: none;
    border: 1px solid var(--border);
    background: var(--card);
    color: var(--text);
    font-size: 14px;
    font-weight: 600;
    font-family: inherit;
    padding: 10px 16px;
    border-radius: 10px;
    cursor: pointer;
    transition: background .15s, border-color .15s, transform .05s;
}

.btn:hover { background: var(--bg-accent); }
.btn:active { transform: translateY(1px); }

.btn.primary {
    background: var(--primary);
    border-color: var(--primary);
    color: var(--primary-fg);
}

.btn.primary:hover { background: var(--primary-hover); border-color: var(--primary-hover); }

.btn.block { display: block; width: 100%; padding: 12px; font-size: 15px; }

.btn:disabled { opacity: .6; cursor: not-allowed; }

/* 提示与结果 ------------------------------------------------------------ */
.hint { margin: 7px 0 0; font-size: 12.5px; color: var(--text-dim); }

.msg { margin: 12px 0 0; font-size: 13px; color: var(--text-dim); min-height: 18px; }
.msg.error { color: var(--err-fg); }
.msg.ok { color: var(--ok-fg); }

.result {
    margin-top: 18px;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 14px;
    background: var(--bg-accent);
}

.result-head {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 10px;
}

.badge {
    display: inline-block;
    font-size: 12px;
    font-weight: 700;
    padding: 2px 9px;
    border-radius: 99px;
}

.badge.ok { background: var(--ok-bg); color: var(--ok-fg); }

.meta { font-size: 12px; color: var(--text-dim); }

.actions { display: flex; align-items: center; gap: 10px; margin-top: 10px; }

/* 页脚 ------------------------------------------------------------------ */
.foot {
    text-align: center;
    color: var(--text-dim);
    font-size: 12.5px;
    margin-top: 8px;
}

.foot a { color: var(--text-dim); }
.foot .dot { margin: 0 7px; opacity: .6; }