/* =========================================================
 * 长沙鲲淼科技 - iOS 26 暖橙琥珀液态玻璃风格设计系统
 * ========================================================= */

:root {
    /* 主色板 - 暖橙琥珀 */
    --primary: #FF6B35;
    --primary-soft: rgba(255, 107, 53, 0.15);
    --accent: #F7B801;
    --accent-2: #C73E1D;
    --gold: #D4A574;
    --success: #2EC4B6;
    --warning: #FF9F1C;

    /* 中性色 - 暖色调 */
    --bg-primary: #FAF6F0;
    --bg-secondary: #F2EBE0;
    --surface: rgba(255, 255, 255, 0.72);
    --surface-strong: rgba(255, 255, 255, 0.88);
    --surface-warm: rgba(255, 247, 235, 0.85);

    --text-primary: #2D1810;
    --text-secondary: #6B4F3F;
    --text-tertiary: #9A8478;

    --border: rgba(115, 70, 30, 0.08);
    --border-strong: rgba(115, 70, 30, 0.16);

    /* 圆角 */
    --r-xs: 8px;
    --r-sm: 12px;
    --r-md: 16px;
    --r-lg: 24px;
    --r-xl: 32px;
    --r-full: 9999px;

    --shadow-sm: 0 2px 6px rgba(115, 70, 30, 0.06);
    --shadow-md: 0 10px 30px rgba(115, 70, 30, 0.10);
    --shadow-lg: 0 24px 50px rgba(115, 70, 30, 0.14);

    --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Helvetica Neue", Helvetica, Arial, sans-serif;
    --t-fast: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --t-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --t-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html, body {
    font-family: var(--font);
    color: var(--text-primary);
    background: var(--bg-primary);
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    overflow-x: hidden;
}

body {
    background:
        radial-gradient(circle at 10% 15%, rgba(255, 107, 53, 0.18), transparent 45%),
        radial-gradient(circle at 90% 75%, rgba(247, 184, 1, 0.20), transparent 45%),
        radial-gradient(circle at 50% 90%, rgba(199, 62, 29, 0.10), transparent 50%),
        var(--bg-primary);
    background-attachment: fixed;
    min-height: 100vh;
}

a { color: inherit; text-decoration: none; transition: color var(--t-fast); }
a:hover { color: var(--primary); }
img { max-width: 100%; height: auto; display: block; }
button { font: inherit; cursor: pointer; border: none; background: none; }
input, textarea, select { font: inherit; }

.container {
    max-width: 1240px;
    margin: 0 auto;
    padding: 0 24px;
}

/* =========================================================
 * 导航 - 暖玻璃左对齐 + 居中菜单 + 右侧 CTA
 * ========================================================= */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 247, 235, 0.78);
    backdrop-filter: blur(28px) saturate(180%);
    -webkit-backdrop-filter: blur(28px) saturate(180%);
    border-bottom: 1px solid var(--border);
    padding: 14px 0;
    z-index: 100;
}

.nav-inner {
    max-width: 1240px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 800;
    font-size: 18px;
    color: var(--text-primary);
}

.nav-logo-icon {
    width: 38px;
    height: 38px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 18px;
    font-weight: 800;
    box-shadow: 0 6px 16px rgba(255, 107, 53, 0.35);
    transform: rotate(-3deg);
    transition: transform var(--t-base);
}

.nav-logo:hover .nav-logo-icon { transform: rotate(0deg) scale(1.05); }

.nav-menu {
    display: flex;
    gap: 6px;
    list-style: none;
}

.nav-menu a {
    padding: 9px 16px;
    border-radius: var(--r-sm);
    font-size: 14.5px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--t-fast);
}

.nav-menu a:hover, .nav-menu a.active {
    color: var(--primary);
    background: var(--primary-soft);
}

.nav-cta {
    background: linear-gradient(135deg, var(--primary), var(--accent-2));
    color: white !important;
    padding: 10px 22px !important;
    border-radius: var(--r-full);
    font-weight: 600 !important;
    box-shadow: 0 8px 20px rgba(255, 107, 53, 0.35);
    transition: all var(--t-fast);
}

.nav-cta:hover {
    background: linear-gradient(135deg, var(--accent-2), var(--primary)) !important;
    color: white !important;
    transform: translateY(-2px);
    box-shadow: 0 12px 28px rgba(255, 107, 53, 0.45);
}

.nav-toggle {
    display: none;
    width: 40px;
    height: 40px;
    border-radius: var(--r-sm);
    background: var(--primary-soft);
    color: var(--primary);
    align-items: center;
    justify-content: center;
    font-size: 18px;
}

@media (max-width: 900px) {
    .nav-menu { display: none; }
    .nav-toggle { display: flex; }
    .nav-menu.open {
        display: flex;
        position: absolute;
        top: 70px;
        left: 16px;
        right: 16px;
        background: var(--surface-strong);
        backdrop-filter: blur(30px);
        flex-direction: column;
        padding: 16px;
        border-radius: var(--r-md);
        gap: 8px;
        box-shadow: var(--shadow-lg);
    }
}

/* =========================================================
 * Hero - 沉浸式横向布局
 * ========================================================= */
.hero {
    padding: 130px 0 70px;
    position: relative;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.15fr 1fr;
    gap: 56px;
    align-items: center;
}

@media (max-width: 900px) {
    .hero-grid { grid-template-columns: 1fr; gap: 36px; text-align: center; }
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: linear-gradient(135deg, var(--primary-soft), rgba(247, 184, 1, 0.15));
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 107, 53, 0.2);
    padding: 8px 18px;
    border-radius: var(--r-full);
    font-size: 13px;
    font-weight: 600;
    color: var(--accent-2);
    margin-bottom: 22px;
    box-shadow: var(--shadow-sm);
}

.hero h1 {
    font-size: clamp(34px, 5.5vw, 58px);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.hero h1 .accent {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.hero p.lead {
    font-size: clamp(15px, 1.8vw, 18px);
    color: var(--text-secondary);
    line-height: 1.75;
    margin-bottom: 32px;
}

.hero-actions {
    display: flex;
    gap: 14px;
    flex-wrap: wrap;
}

@media (max-width: 900px) { .hero-actions { justify-content: center; } }

/* Hero 图片：层叠卡片效果 */
.hero-visual {
    position: relative;
    height: 460px;
}

.hero-visual-card {
    position: absolute;
    border-radius: var(--r-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    border: 4px solid white;
}

.hero-visual-card-1 {
    width: 70%;
    height: 80%;
    top: 0;
    right: 0;
    z-index: 2;
}

.hero-visual-card-2 {
    width: 55%;
    height: 50%;
    bottom: 0;
    left: 0;
    z-index: 3;
}

.hero-visual-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-stat {
    position: absolute;
    bottom: 20%;
    right: 0;
    background: var(--surface-strong);
    backdrop-filter: blur(30px);
    padding: 14px 18px;
    border-radius: var(--r-md);
    box-shadow: var(--shadow-md);
    z-index: 4;
    border: 1px solid var(--border);
}

.hero-stat-num {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
}

.hero-stat-label {
    font-size: 12px;
    color: var(--text-tertiary);
}

@media (max-width: 900px) {
    .hero-visual { height: 320px; }
}

/* =========================================================
 * 数据滚动条
 * ========================================================= */
.stats-strip {
    background: linear-gradient(135deg, var(--primary), var(--accent-2));
    padding: 36px 0;
    margin-top: 40px;
    overflow: hidden;
    border-radius: var(--r-lg);
    color: white;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    text-align: center;
}

.stats-grid-item .num {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 4px;
    letter-spacing: -0.02em;
}

.stats-grid-item .label {
    font-size: 13px;
    opacity: 0.9;
}

@media (max-width: 640px) {
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .stats-grid-item .num { font-size: 28px; }
}

/* =========================================================
 * 通用区块
 * ========================================================= */
.section {
    padding: 80px 0;
    position: relative;
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
}

.section-title small {
    display: inline-block;
    font-size: 13px;
    font-weight: 700;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 14px;
    padding: 5px 16px;
    background: var(--primary-soft);
    border-radius: var(--r-full);
    border: 1px solid rgba(255, 107, 53, 0.2);
}

.section-title h2 {
    font-size: clamp(28px, 4vw, 42px);
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 14px;
    color: var(--text-primary);
}

.section-title p {
    color: var(--text-secondary);
    font-size: 16px;
    max-width: 640px;
    margin: 0 auto;
}

/* =========================================================
 * 按钮
 * ========================================================= */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 30px;
    border-radius: var(--r-full);
    font-weight: 600;
    font-size: 15px;
    transition: all var(--t-fast);
    cursor: pointer;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--accent-2));
    color: white;
    box-shadow: 0 10px 26px rgba(255, 107, 53, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    color: white;
    box-shadow: 0 14px 34px rgba(255, 107, 53, 0.45);
}

.btn-glass {
    background: var(--surface-strong);
    backdrop-filter: blur(20px);
    color: var(--text-primary);
    border: 1px solid var(--border-strong);
    box-shadow: var(--shadow-sm);
}

.btn-glass:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* =========================================================
 * 玻璃卡片
 * ========================================================= */
.glass-card {
    background: var(--surface-strong);
    backdrop-filter: blur(28px) saturate(180%);
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    padding: 28px;
    transition: all var(--t-base);
    box-shadow: var(--shadow-sm);
}

.glass-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

/* =========================================================
 * 课程分类标签
 * ========================================================= */
.category-tabs {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 36px;
}

.category-tab {
    padding: 9px 20px;
    background: var(--surface-strong);
    border: 1px solid var(--border);
    border-radius: var(--r-full);
    font-size: 13.5px;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--t-fast);
}

.category-tab:hover {
    color: var(--primary);
    border-color: var(--primary);
}

.category-tab.active {
    background: linear-gradient(135deg, var(--primary), var(--accent-2));
    color: white;
    border-color: transparent;
    box-shadow: 0 6px 16px rgba(255, 107, 53, 0.3);
}

/* =========================================================
 * 课程卡（横向 + 纵向混合）
 * ========================================================= */
.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}

.course-card {
    background: white;
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    overflow: hidden;
    transition: all var(--t-base);
    box-shadow: var(--shadow-sm);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    text-decoration: none;
    color: inherit;
}

.course-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.course-card-img {
    height: 180px;
    overflow: hidden;
    position: relative;
}

.course-card-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--t-slow);
}

.course-card:hover .course-card-img img { transform: scale(1.08); }

.course-card-tag {
    position: absolute;
    top: 14px;
    left: 14px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    padding: 5px 12px;
    border-radius: var(--r-full);
    font-size: 12px;
    font-weight: 700;
    box-shadow: 0 4px 12px rgba(255, 107, 53, 0.3);
}

.course-card-cat {
    position: absolute;
    bottom: 14px;
    left: 14px;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    color: var(--primary);
    padding: 4px 10px;
    border-radius: var(--r-xs);
    font-size: 11px;
    font-weight: 600;
}

.course-card-body {
    padding: 22px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.course-card-title {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 10px;
    line-height: 1.45;
    color: var(--text-primary);
}

.course-card-desc {
    font-size: 13.5px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 18px;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.course-card-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 16px;
    border-top: 1px dashed var(--border-strong);
}

.course-card-price {
    font-size: 22px;
    font-weight: 800;
    color: var(--accent-2);
}

.course-card-price small {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-tertiary);
    text-decoration: line-through;
    margin-left: 6px;
}

.course-card-info {
    display: flex;
    gap: 12px;
    font-size: 12px;
    color: var(--text-tertiary);
}

/* =========================================================
 * 企业合作案例
 * ========================================================= */
.case-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.case-card {
    background: white;
    border-radius: var(--r-lg);
    padding: 28px;
    border: 1px solid var(--border);
    transition: all var(--t-base);
    box-shadow: var(--shadow-sm);
}

.case-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}

.case-card-logo {
    width: 56px;
    height: 56px;
    border-radius: var(--r-md);
    background: linear-gradient(135deg, var(--primary-soft), rgba(247, 184, 1, 0.15));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-bottom: 16px;
}

.case-card h4 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 8px;
}

.case-card p {
    font-size: 13.5px;
    color: var(--text-secondary);
    line-height: 1.65;
    margin-bottom: 14px;
}

.case-card-meta {
    display: flex;
    gap: 16px;
    font-size: 12px;
    color: var(--text-tertiary);
    padding-top: 14px;
    border-top: 1px solid var(--border);
}

/* =========================================================
 * 评价
 * ========================================================= */
.review-item {
    display: flex;
    gap: 14px;
    padding: 20px;
    background: white;
    border-radius: var(--r-md);
    border: 1px solid var(--border);
    margin-bottom: 12px;
    transition: all var(--t-fast);
}

.review-item:hover {
    border-color: var(--primary);
    transform: translateX(4px);
}

.review-avatar {
    width: 46px;
    height: 46px;
    border-radius: var(--r-full);
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
    font-size: 17px;
}

.review-content { flex: 1; }
.review-head {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 6px;
    flex-wrap: wrap;
}

.review-name { font-weight: 600; font-size: 14px; }
.review-stars { color: var(--accent); font-size: 13px; letter-spacing: 1px; }
.review-time { margin-left: auto; font-size: 12px; color: var(--text-tertiary); }
.review-text { font-size: 14px; color: var(--text-secondary); line-height: 1.65; }

/* =========================================================
 * 表单
 * ========================================================= */
.form-group { margin-bottom: 18px; }

.form-label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.form-input, .form-select, .form-textarea {
    width: 100%;
    padding: 13px 16px;
    background: white;
    border: 1.5px solid var(--border-strong);
    border-radius: var(--r-md);
    font-size: 14px;
    color: var(--text-primary);
    transition: all var(--t-fast);
}

.form-input:focus, .form-select:focus, .form-textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px var(--primary-soft);
}

.form-textarea { min-height: 100px; resize: vertical; }

/* =========================================================
 * 页脚
 * ========================================================= */
.footer {
    background: linear-gradient(180deg, transparent, rgba(115, 70, 30, 0.05));
    border-top: 1px solid var(--border);
    padding: 60px 0 30px;
    margin-top: 80px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    font-weight: 700;
    font-size: 18px;
}

.footer-desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
    max-width: 320px;
}

.footer h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.footer ul { list-style: none; }
.footer ul li { margin-bottom: 10px; }
.footer ul a { font-size: 13.5px; color: var(--text-secondary); }
.footer ul a:hover { color: var(--primary); }

.footer-bottom {
    padding-top: 30px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 13px;
    color: var(--text-tertiary);
}

.footer-bottom a { color: var(--text-secondary); }
.footer-bottom a:hover { color: var(--primary); }

@media (max-width: 768px) {
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 30px; }
    .footer-brand { grid-column: 1 / -1; }
}

/* =========================================================
 * 返回顶部 - 圆角方块
 * ========================================================= */
.back-to-top {
    position: fixed;
    right: 24px;
    bottom: 100px;
    width: 50px;
    height: 50px;
    background: white;
    border: 1.5px solid var(--primary);
    border-radius: var(--r-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    font-size: 22px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all var(--t-base);
    box-shadow: var(--shadow-md);
    z-index: 99;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-3px) rotate(-2deg);
}

/* =========================================================
 * AI 客服 - 鲲鹏意象
 * ========================================================= */
.ai-chat-btn {
    position: fixed;
    right: 24px;
    bottom: 30px;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary), var(--accent-2));
    border-radius: var(--r-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 26px;
    cursor: pointer;
    box-shadow: 0 12px 30px rgba(255, 107, 53, 0.4);
    transition: all var(--t-base);
    z-index: 99;
    transform: rotate(-4deg);
}

.ai-chat-btn:hover {
    transform: rotate(0) scale(1.06);
    box-shadow: 0 16px 36px rgba(255, 107, 53, 0.55);
}

.ai-chat-btn::after {
    content: '';
    position: absolute;
    inset: -4px;
    border-radius: inherit;
    border: 2px solid var(--primary);
    opacity: 0;
    animation: ring 2.4s infinite;
}

@keyframes ring {
    0% { transform: scale(0.95); opacity: 0.7; }
    70% { transform: scale(1.3); opacity: 0; }
    100% { opacity: 0; }
}

.ai-chat-panel {
    position: fixed;
    right: 24px;
    bottom: 100px;
    width: 360px;
    max-width: calc(100vw - 48px);
    height: 480px;
    background: var(--surface-strong);
    backdrop-filter: blur(40px) saturate(180%);
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    box-shadow: var(--shadow-lg);
    z-index: 98;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px) scale(0.95);
    transform-origin: bottom right;
    transition: all var(--t-base);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.ai-chat-panel.open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.ai-chat-header {
    padding: 18px 20px;
    background: linear-gradient(135deg, var(--primary), var(--accent-2));
    color: white;
    display: flex;
    align-items: center;
    gap: 12px;
}

.ai-chat-header-avatar {
    width: 38px;
    height: 38px;
    background: rgba(255, 255, 255, 0.25);
    border-radius: var(--r-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
}

.ai-chat-header-info { flex: 1; }
.ai-chat-header-info h4 { font-size: 15px; font-weight: 700; margin-bottom: 2px; }
.ai-chat-header-info p { font-size: 12px; opacity: 0.85; }

.ai-chat-body {
    flex: 1;
    padding: 18px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.ai-chat-msg {
    max-width: 80%;
    padding: 10px 14px;
    border-radius: var(--r-md);
    font-size: 14px;
    line-height: 1.5;
}

.ai-chat-msg.bot {
    background: var(--bg-secondary);
    color: var(--text-primary);
    align-self: flex-start;
    border-bottom-left-radius: 4px;
}

.ai-chat-msg.user {
    background: linear-gradient(135deg, var(--primary), var(--accent-2));
    color: white;
    align-self: flex-end;
    border-bottom-right-radius: 4px;
}

.ai-chat-input {
    padding: 14px;
    border-top: 1px solid var(--border);
    display: flex;
    gap: 8px;
}

.ai-chat-input input {
    flex: 1;
    padding: 10px 14px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--r-full);
    font-size: 14px;
    outline: none;
}

.ai-chat-input input:focus { border-color: var(--primary); }

.ai-chat-input button {
    background: var(--primary);
    color: white;
    width: 38px;
    height: 38px;
    border-radius: var(--r-full);
    font-size: 16px;
}

@media (max-width: 640px) {
    .container { padding: 0 16px; }
    .hero { padding: 100px 0 50px; }
    .section { padding: 50px 0; }
    .ai-chat-panel { right: 12px; bottom: 88px; width: calc(100% - 24px); height: 60vh; }
    .ai-chat-btn { right: 16px; bottom: 16px; }
    .back-to-top { right: 16px; bottom: 90px; }
}