/* ============ 教学特色 · AI 三环节 ============ */
.features{
    padding: 96px 0;
    background:
        linear-gradient(180deg, #F8FBFF 0%, #FFFFFF 100%);
    position: relative;
    overflow: hidden;
}
.features::before{
    content:"";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(500px 260px at 15% 20%, rgba(46,107,230,.10) 0%, transparent 65%),
        radial-gradient(500px 260px at 85% 80%, rgba(255,122,69,.10) 0%, transparent 65%);
    pointer-events: none;
}
.features > .container{ position: relative; z-index: 1; }

/* lead 里的强调 */
.features .section-head .lead strong{
    color: var(--color-primary);
    font-weight: 600;
    letter-spacing: .3px;
}

/* ---- 三卡片流程 ---- */
.feature-flow{
    display: grid;
    grid-template-columns: 1fr 40px 1fr 40px 1fr;
    gap: 12px;
    align-items: stretch;
    margin-bottom: 40px;
}
.feature-card{
    position: relative;
    padding: 36px 28px 32px;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s var(--ease);
    display: flex;
    flex-direction: column;
}
.feature-card:hover{
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(46,107,230,.35);
}
.feature-card.featured{
    background: linear-gradient(160deg, var(--color-primary) 0%, #1B50BF 100%);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 20px 45px rgba(46,107,230,.25);
}
.feature-card.featured h3,
.feature-card.featured .feature-num{
    color: #fff;
}

.feature-num{
    position: absolute;
    top: 20px; right: 22px;
    font-size: 44px;
    font-weight: 800;
    color: var(--color-primary);
    opacity: .12;
    letter-spacing: -1px;
    line-height: 1;
}
.feature-card.featured .feature-num{
    opacity: .25;
}

.feature-icon{
    width: 56px;
    height: 56px;
    border-radius: 16px;
    background: var(--color-primary-light);
    color: var(--color-primary);
    display: grid;
    place-items: center;
    margin-bottom: 20px;
    transition: background .3s var(--ease);
}
.feature-icon svg{ width: 28px; height: 28px; }
.feature-card:hover .feature-icon{ background: var(--color-primary); color: #fff; }
.feature-card.featured .feature-icon{
    background: rgba(255,255,255,.18);
    color: #fff;
}
.feature-card.featured:hover .feature-icon{
    background: rgba(255,255,255,.28);
}

.feature-card h3{
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -0.2px;
}
.feature-sub{
    font-size: 14.5px;
    line-height: 1.65;
    color: var(--color-text-light);
    margin-bottom: 18px;
}
.feature-card.featured .feature-sub{
    color: rgba(255,255,255,.85);
}

.feature-points{
    display: grid;
    gap: 10px;
    padding-top: 16px;
    border-top: 1px dashed var(--color-border);
    margin-top: auto;
}
.feature-card.featured .feature-points{
    border-top-color: rgba(255,255,255,.25);
}
.feature-points li{
    display: flex;
    align-items: flex-start;
    gap: 8px;
    font-size: 14px;
    color: var(--color-text);
    line-height: 1.55;
}
.feature-points li::before{
    content: "";
    flex-shrink: 0;
    width: 6px; height: 6px;
    border-radius: 50%;
    background: var(--color-primary);
    margin-top: 8px;
}
.feature-card.featured .feature-points li{ color: rgba(255,255,255,.92); }
.feature-card.featured .feature-points li::before{ background: var(--color-accent); }

.feature-arrow{
    display: grid;
    place-items: center;
    color: var(--color-primary);
    opacity: .55;
}
.feature-arrow svg{ width: 32px; height: 18px; }

/* ---- 底部高亮条 ---- */
.features-highlight{
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 24px;
    align-items: center;
    padding: 28px 32px;
    background: linear-gradient(100deg, #FFF3EB 0%, #EEF4FF 100%);
    border: 1px solid rgba(255,122,69,.25);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}
.hl-icon{
    width: 56px; height: 56px;
    border-radius: 14px;
    background: linear-gradient(135deg, var(--color-accent), #FF9A6E);
    color: #fff;
    display: grid; place-items: center;
    box-shadow: 0 8px 20px rgba(255,122,69,.3);
}
.hl-icon svg{ width: 28px; height: 28px; }
.hl-body strong{
    display: block;
    font-size: 18px;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 4px;
}
.hl-body p{
    font-size: 14.5px;
    color: var(--color-text-light);
    line-height: 1.65;
    margin: 0;
}
.hl-body p b{
    color: var(--color-primary);
    font-weight: 700;
}

/* ---- 响应式 ---- */
@media (max-width: 1024px){
    .feature-flow{
        grid-template-columns: 1fr;
        gap: 16px;
    }
    .feature-arrow{
        transform: rotate(90deg);
        padding: 4px 0;
    }
    .features-highlight{
        grid-template-columns: 1fr;
        text-align: center;
        padding: 24px;
    }
    .hl-icon{ margin: 0 auto; }
}
@media (max-width: 600px){
    .features{ padding: 56px 0; }
    .feature-card{ padding: 28px 22px; }
    .feature-card h3{ font-size: 19px; }
    .feature-num{ font-size: 36px; top: 14px; right: 16px; }
}

/* ---- 补习痛点提示 ---- */
.pain-grid{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
    margin: 0 0 34px;
}
.pain-grid article{
    padding: 18px 16px;
    background: rgba(255,255,255,.86);
    border: 1px solid rgba(220,38,38,.12);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}
.pain-grid strong{
    display: block;
    color: #B91C1C;
    font-size: 15px;
    margin-bottom: 6px;
}
.pain-grid span{
    display: block;
    color: var(--color-text-light);
    font-size: 13.5px;
    line-height: 1.6;
}
@media (max-width: 1024px){
    .pain-grid{ grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px){
    .pain-grid{ grid-template-columns: 1fr; }
}