/* ===== 响应式 ===== */
@media (max-width: 920px) {
    .spec-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .pricing-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .multimodal-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .auth-entry {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    .demo-output-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .multimodal-grid {
        grid-template-columns: 1fr;
    }
    .pricing-grid {
        grid-template-columns: 1fr;
        max-width: 340px;
        margin-left: auto;
        margin-right: auto;
    }
    .spec-grid {
        grid-template-columns: 1fr 1fr;
        gap: 0.8rem;
    }
    #typewriter-text {
        font-size: 2rem;
    }
    .cursor {
        height: 2rem;
    }
    .navbar {
        flex-wrap: wrap;
        justify-content: center;
        gap: 0.8rem;
        padding: 0.8rem 1.2rem;
        top: 0.5rem;
    }
    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 0.4rem;
    }
    .hero {
        padding: 2rem 1rem 2.5rem;
    }
    .section-title {
        font-size: 1.8rem;
    }
    .demo-content-area {
        padding: 1rem;
        font-size: 0.82rem;
    }
    .auth-entry-card {
        padding: 2rem 1.5rem;
    }
    .paygo-section {
        flex-direction: column;
        gap: 1rem;
        padding: 1.2rem;
    }
    .cta-group .btn-primary,
    .cta-group .btn-secondary {
        width: 100%;
        max-width: 280px;
        text-align: center;
    }
    .demo-container .demo-header .demo-speed {
        margin-left: 0;
        width: 100%;
        text-align: center;
    }
    .demo-container .demo-header .demo-replay-btn {
        margin-left: auto;
    }
    .demo-output-grid {
        grid-template-columns: 1fr 1fr;
        gap: 0.5rem;
    }
    .demo-output-item {
        padding: 0.8rem 0.5rem;
    }
    .demo-output-item svg {
        width: 24px;
        height: 24px;
    }
}

.section-anchor {
    scroll-margin-top: 100px;
}
::selection {
    background: #0071e3;
    color: white;
}
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}
::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.02);
    border-radius: 20px;
}
::-webkit-scrollbar-thumb {
    background: #c6c6c8;
    border-radius: 20px;
}
::-webkit-scrollbar-thumb:hover {
    background: #a8a8aa;
}

.speed-dot {
    display: inline-block;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #34c759;
    animation: pulse-dot 1.2s ease-in-out infinite;
    margin-right: 6px;
}

@keyframes pulse-dot {
    0%,
    100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.5;
        transform: scale(0.8);
    }
}

.demo-replay-btn:active {
    transform: scale(0.95);
}

/* ===== 界线标记 ===== */
.section-boundary {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding: 0.5rem 0;
    color: #b0b0b5;
    font-size: 0.7rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    font-weight: 500;
}

.section-boundary::before,
.section-boundary::after {
    content: '';
    flex: 1;
    height: 1px;
    background: linear-gradient(to right, transparent, rgba(0, 0, 0, 0.06));
}

.section-boundary::after {
    background: linear-gradient(to left, transparent, rgba(0, 0, 0, 0.06));
}