* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            user-select: none;
        }

        body {
            font-family: 'Segoe UI', 'Roboto', 'Inter', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', monospace;
            background: linear-gradient(145deg, #e9f0f5 0%, #d9e2ec 100%);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 1.5rem;
            transition: background 0.3s ease, color 0.2s ease;
        }

        body.dark {
            background: linear-gradient(145deg, #1a2a32 0%, #0f1a1f 100%);
        }

        .clock-card {
            max-width: 1000px;
            width: 100%;
            background: rgba(255, 255, 255, 0.92);
            backdrop-filter: blur(12px);
            border-radius: 3rem;
            padding: 2rem 1.8rem 1.8rem 1.8rem;
            box-shadow: 0 30px 50px rgba(0, 0, 0, 0.2), 0 0 0 1px rgba(255, 255, 255, 0.5);
            transition: all 0.3s ease;
            text-align: center;
        }

        body.dark .clock-card {
            background: rgba(25, 35, 45, 0.88);
            backdrop-filter: blur(12px);
            box-shadow: 0 30px 45px rgba(0, 0, 0, 0.4), 0 0 0 1px rgba(255, 255, 255, 0.08);
        }

        .title-section {
            display: flex;
            align-items: baseline;
            justify-content: center;
            gap: 12px;
            flex-wrap: wrap;
            margin-bottom: 1.5rem;
        }

        .title-section h1 {
            font-size: 2rem;
            font-weight: 600;
            letter-spacing: 1px;
            background: linear-gradient(135deg, #1e4d76, #0e6b3e);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
        }

        body.dark .title-section h1 {
            background: linear-gradient(135deg, #7bc5ae, #c0e0c8);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
        }

        .beijing-badge {
            background: #c72a2f;
            color: white;
            padding: 0.2rem 1rem;
            border-radius: 40px;
            font-size: 0.8rem;
            font-weight: 600;
            letter-spacing: 1px;
        }

        .time-container {
            display: flex;
            align-items: baseline;
            justify-content: center;
            flex-wrap: wrap;
            gap: 4px;
            margin: 0.5rem 0 0.2rem 0;
        }

        .time-hms {
            font-size: 4.5rem;
            font-weight: 800;
            font-family: 'JetBrains Mono', 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
            letter-spacing: 2px;
            background: linear-gradient(145deg, #1e2a36, #2c3e2f);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
            text-shadow: 2px 2px 12px rgba(0,0,0,0.05);
            line-height: 1.2;
        }

        .time-ms {
            font-size: 2.25rem;
            font-weight: 600;
            font-family: 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;
            background: linear-gradient(145deg, #4a6a5a, #2c5a4a);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
            letter-spacing: 0px;
            margin-left: 4px;
            opacity: 0.85;
        }

        @media (max-width: 768px) {
            .clock-card {
                padding: 1.5rem 1.2rem 1.2rem 1.2rem;
            }
            .title-section h1 {
                font-size: 1.8rem;
            }
            .time-hms { font-size: 3.5rem; }
            .time-ms { font-size: 1.75rem; }
            .date-info {
                font-size: 1.5rem;
            }
            .weekday {
                font-size: 1.1rem;
            }
        }

        @media (max-width: 600px) {
            .time-hms { font-size: 2.8rem; }
            .time-ms { font-size: 1.4rem; }
            .date-info {
                font-size: 1.3rem;
            }
            .extra-panel {
                gap: 0.8rem;
            }
            .info-chip {
                font-size: 0.8rem;
                padding: 0.3rem 1rem;
            }
        }

        @media (max-width: 480px) {
            body {
                padding: 1rem;
            }
            .clock-card {
                border-radius: 2rem;
                padding: 1.2rem 1rem 1rem 1rem;
            }
            .title-section h1 {
                font-size: 1.5rem;
            }
            .time-hms { font-size: 2.2rem; }
            .time-ms { font-size: 1.1rem; }
            .date-info {
                font-size: 1.1rem;
            }
            .weekday {
                font-size: 1rem;
                padding: 0.15rem 1rem;
            }
            .extra-panel {
                flex-direction: column;
                align-items: center;
            }
            .info-chip {
                width: 100%;
                max-width: 200px;
                justify-content: center;
            }
            .friendship-links {
                gap: 0.8rem;
                font-size: 0.8rem;
            }
        }

        @media (max-width: 360px) {
            .time-hms { font-size: 1.8rem; }
            .time-ms { font-size: 0.9rem; }
            .date-info {
                font-size: 1rem;
            }
            .title-section {
                flex-direction: column;
                align-items: center;
                gap: 0.5rem;
            }
        }

        body.dark .time-hms {
            background: linear-gradient(145deg, #eef4ff, #c2e0d0);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
        }

        body.dark .time-ms {
            background: linear-gradient(145deg, #b8dec8, #8fc0a8);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
        }

        .date-info {
            font-size: 1.7rem;
            font-weight: 500;
            margin-bottom: 0.5rem;
            color: #2c5a3a;
        }

        body.dark .date-info {
            color: #bdd9c7;
        }

        .weekday {
            font-size: 1.3rem;
            font-weight: 500;
            background: rgba(0,0,0,0.05);
            display: inline-block;
            padding: 0.2rem 1.2rem;
            border-radius: 40px;
            margin-top: 0.25rem;
            color: #2c5a4a;
        }

        body.dark .weekday {
            background: rgba(255,255,240,0.08);
            color: #cbddcf;
        }

        .extra-panel {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 1rem;
            margin: 1.5rem 0 1.2rem 0;
        }

        .info-chip {
            background: rgba(245, 248, 250, 0.8);
            border-radius: 60px;
            padding: 0.4rem 1.2rem;
            font-size: 0.85rem;
            font-weight: 500;
            display: inline-flex;
            align-items: center;
            gap: 8px;
            backdrop-filter: blur(4px);
            color: #1f4e3a;
        }

        body.dark .info-chip {
            background: rgba(30, 45, 55, 0.7);
            color: #caddd2;
        }

        .theme-toggle {
            position: fixed;
            bottom: 1.8rem;
            right: 1.8rem;
            background: #1f3b2c;
            color: white;
            width: 48px;
            height: 48px;
            border-radius: 60px;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: 0 8px 18px rgba(0,0,0,0.2);
            transition: all 0.2s ease;
            border: none;
            font-size: 1.4rem;
            z-index: 100;
        }

        .theme-toggle:hover {
            transform: scale(1.05);
            background: #0c2b1e;
        }

        body.dark .theme-toggle {
            background: #cbd5c3;
            color: #1f3b2c;
        }

        .divider {
            width: 60px;
            height: 3px;
            background: #b8cfc0;
            margin: 0.6rem auto;
            border-radius: 4px;
        }

        .precision-badge {
            font-size: 0.7rem;
            background: rgba(0,0,0,0.04);
            display: inline-block;
            padding: 0.2rem 0.8rem;
            border-radius: 20px;
            margin-top: 0.5rem;
            font-family: monospace;
        }

        .footer-links {
            margin-top: 2rem;
            padding-top: 1.2rem;
            border-top: 1px solid rgba(0,0,0,0.08);
            text-align: center;
        }

        body.dark .footer-links {
            border-top-color: rgba(255,255,255,0.1);
        }

        .friendship-links {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 1.2rem;
            margin-bottom: 1rem;
            font-size: 0.85rem;
        }

        .friendship-links a {
            color: #3a6b55;
            text-decoration: none;
            transition: color 0.2s;
            display: inline-flex;
            align-items: center;
            gap: 5px;
        }

        .friendship-links a:hover {
            color: #1f5e3a;
            text-decoration: underline;
        }

        body.dark .friendship-links a {
            color: #9fc7b5;
        }

        .copyright {
            font-size: 0.7rem;
            color: #6f8f7c;
            margin: 0.6rem 0 0.3rem 0;
        }

        .icp {
            font-size: 0.7rem;
            color: #6f8f7c;
        }

        .icp a {
            color: inherit;
            text-decoration: none;
        }

        .icp a:hover {
            text-decoration: underline;
        }