:root {
            --bg: #f5f7fb;
            --card: #ffffff;
            --text: #1d2a3a;
            --primary: #0f766e;
            --primary-hover: #0d635d;
            --border: #dbe4f0;
        }
        * { box-sizing: border-box; }
        body {
            margin: 0;
            min-height: 100vh;
            display: grid;
            place-items: center;
            padding: 16px;
            background: linear-gradient(160deg, #edf2ff, var(--bg));
            font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
            color: var(--text);
        }
        .card {
            width: 100%;
            max-width: 420px;
            background: var(--card);
            border: 1px solid var(--border);
            border-radius: 14px;
            padding: 16px;
            box-shadow: 0 10px 24px rgba(11, 45, 78, 0.08);
        }
        .title {
            font-size: 1.15rem;
            font-weight: 700;
            margin-bottom: 10px;
        }
        .input {
            width: 100%;
            border: 1px solid var(--border);
            border-radius: 10px;
            padding: 10px 12px;
            font-size: 1rem;
            margin-bottom: 10px;
        }
        .btn {
            width: 100%;
            border: none;
            border-radius: 10px;
            padding: 11px;
            font-size: 1rem;
            font-weight: 600;
            color: #fff;
            background: var(--primary);
            cursor: pointer;
        }
        .btn:hover { background: var(--primary-hover); }
        .msg {
            min-height: 1.3em;
            margin-top: 8px;
            color: #b42318;
            font-size: 0.92rem;
        }