/* 破题搭子官网样式
   品牌色：豆绿 + 米白 + 河狸暖棕
   纯静态，无外部字体和框架依赖 */

:root {
    --bg: #f8f5ec;
    --bg-soft: #f2efe4;
    --surface: #ffffff;
    --ink: #1f2a24;
    --ink-soft: #34453a;
    --muted: #66746a;
    --muted-light: #8a968d;
    --green: #4f7a5a;
    --green-dark: #35563f;
    --green-deep: #22382b;
    --green-soft: #e7efe6;
    --green-pale: #f0f5ee;
    --amber: #c98245;
    --amber-soft: #f8ecdf;
    --red: #c25a4d;
    --red-soft: #faece9;
    --line: #e1e5da;
    --line-strong: #cfd7c9;
    --shadow-sm: 0 8px 24px rgba(43, 64, 48, 0.06);
    --shadow: 0 18px 50px rgba(43, 64, 48, 0.1);
    --shadow-lg: 0 30px 80px rgba(43, 64, 48, 0.14);
    --radius-sm: 14px;
    --radius: 22px;
    --radius-lg: 30px;
    --container: 1180px;
    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 96px;
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: var(--font);
    font-size: 16px;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    overflow-x: hidden;
}

body.nav-open {
    overflow: hidden;
}

img,
svg {
    display: block;
    max-width: 100%;
}

.svg-sprite {
    position: absolute;
    width: 0;
    height: 0;
    overflow: hidden;
}

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

button {
    font: inherit;
    color: inherit;
    border: 0;
    background: none;
    cursor: pointer;
}

h1,
h2,
h3,
h4,
p,
ul,
ol {
    margin: 0;
}

ul,
ol {
    padding: 0;
    list-style: none;
}

::selection {
    background: rgba(79, 122, 90, 0.22);
}

:focus-visible {
    outline: 3px solid rgba(79, 122, 90, 0.45);
    outline-offset: 3px;
    border-radius: 6px;
}

/* ---------- 背景 ---------- */

.page-bg {
    position: fixed;
    inset: 0;
    z-index: -2;
    background: radial-gradient(900px 520px at 88% -6%, rgba(127, 163, 107, 0.2), transparent 64%),
        radial-gradient(760px 460px at -4% 8%, rgba(201, 130, 69, 0.11), transparent 62%),
        linear-gradient(180deg, #faf7ef 0%, #f7f3e9 48%, #f3f0e5 100%);
}

.page-bg::after {
    content: "";
    position: absolute;
    inset: 0;
    background-image: linear-gradient(rgba(79, 122, 90, 0.045) 1px, transparent 1px),
        linear-gradient(90deg, rgba(79, 122, 90, 0.045) 1px, transparent 1px);
    background-size: 58px 58px;
    -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.75), transparent 62%);
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.75), transparent 62%);
    pointer-events: none;
}

.skip-link {
    position: absolute;
    left: 16px;
    top: -60px;
    z-index: 200;
    padding: 10px 16px;
    border-radius: 10px;
    background: var(--green-dark);
    color: #fff;
    transition: top 0.2s ease;
}

.skip-link:focus {
    top: 16px;
}

.container {
    width: min(100% - 48px, var(--container));
    margin-inline: auto;
}

/* ---------- 顶部导航 ---------- */

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(248, 245, 236, 0.78);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid transparent;
    transition: border-color 0.25s ease, box-shadow 0.25s ease, background 0.25s ease;
}

.site-header.is-scrolled {
    background: rgba(250, 247, 239, 0.94);
    border-bottom-color: var(--line);
    box-shadow: 0 10px 30px rgba(43, 64, 48, 0.06);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    min-height: 78px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

.brand img {
    width: 46px;
    height: 46px;
    border-radius: 15px;
    object-fit: cover;
    background: #fff;
    box-shadow: 0 4px 14px rgba(43, 64, 48, 0.12);
}

.brand-name {
    font-size: 20px;
    font-weight: 800;
    letter-spacing: 0.02em;
    color: var(--ink);
}

.brand-sub {
    display: block;
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.14em;
    color: var(--muted);
    line-height: 1.2;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 30px;
    margin-left: auto;
    margin-right: 8px;
}

.main-nav a {
    font-size: 14px;
    font-weight: 600;
    color: var(--ink-soft);
    transition: color 0.2s ease;
    white-space: nowrap;
}

.main-nav a:hover {
    color: var(--green);
}

.main-nav .nav-login {
    display: none;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 10px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 9px;
    min-height: 42px;
    padding: 0 20px;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 700;
    line-height: 1;
    white-space: nowrap;
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease,
        border-color 0.2s ease, color 0.2s ease;
}

.btn svg {
    width: 17px;
    height: 17px;
}

.btn-primary {
    color: #fff;
    background: linear-gradient(135deg, #557f5e, #3f684b);
    box-shadow: 0 10px 24px rgba(63, 104, 75, 0.26);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 14px 30px rgba(63, 104, 75, 0.32);
}

.btn-secondary {
    color: var(--ink);
    background: rgba(255, 255, 255, 0.72);
    border: 1px solid var(--line-strong);
}

.btn-secondary:hover {
    background: #fff;
    border-color: var(--green);
    transform: translateY(-1px);
}

.btn-ghost {
    color: var(--ink-soft);
    padding-inline: 14px;
}

.btn-ghost:hover {
    color: var(--green);
}

.btn-lg {
    min-height: 52px;
    padding-inline: 28px;
    font-size: 15px;
}

.nav-toggle {
    display: none;
    width: 44px;
    height: 44px;
    border-radius: 12px;
    border: 1px solid var(--line-strong);
    background: rgba(255, 255, 255, 0.7);
    align-items: center;
    justify-content: center;
}

.nav-toggle span {
    position: relative;
    display: block;
    width: 18px;
    height: 2px;
    border-radius: 2px;
    background: var(--ink);
    transition: transform 0.25s ease, background 0.25s ease;
}

.nav-toggle span::before,
.nav-toggle span::after {
    content: "";
    position: absolute;
    left: 0;
    width: 18px;
    height: 2px;
    border-radius: 2px;
    background: var(--ink);
    transition: transform 0.25s ease, top 0.25s ease;
}

.nav-toggle span::before {
    top: -6px;
}

.nav-toggle span::after {
    top: 6px;
}

.nav-open .nav-toggle span {
    background: transparent;
}

.nav-open .nav-toggle span::before {
    top: 0;
    transform: rotate(45deg);
}

.nav-open .nav-toggle span::after {
    top: 0;
    transform: rotate(-45deg);
}

/* ---------- 通用区块 ---------- */

.section {
    padding: 92px 0;
}

.section-tint {
    background: linear-gradient(180deg, rgba(231, 239, 230, 0.62), rgba(240, 245, 238, 0.4));
    border-block: 1px solid rgba(79, 122, 90, 0.09);
}

.section-head {
    max-width: 700px;
    margin-bottom: 48px;
}

.section-head.center {
    margin-inline: auto;
    text-align: center;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    padding: 7px 13px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.72);
    border: 1px solid rgba(79, 122, 90, 0.16);
    color: var(--green-dark);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.08em;
}

.eyebrow .dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--green);
    box-shadow: 0 0 0 4px rgba(79, 122, 90, 0.12);
}

.eyebrow.plain {
    background: transparent;
    border: 0;
    padding: 0;
}

.section-head h2 {
    font-size: clamp(30px, 3.6vw, 44px);
    line-height: 1.18;
    letter-spacing: -0.02em;
    font-weight: 800;
}

.section-head p {
    margin-top: 16px;
    color: var(--muted);
    font-size: 16px;
    line-height: 1.8;
}

.grad {
    color: var(--green-dark);
    background: linear-gradient(100deg, #386046 8%, #6f9964 58%, #9aae6f 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* ---------- 首屏 ---------- */

.hero {
    padding: 66px 0 40px;
}

.hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.04fr) minmax(0, 0.96fr);
    gap: 64px;
    align-items: center;
}

.hero-copy h1 {
    margin: 18px 0 0;
    font-size: clamp(38px, 4.9vw, 62px);
    line-height: 1.12;
    letter-spacing: -0.035em;
    font-weight: 850;
}

.hero-copy .lede {
    max-width: 540px;
    margin-top: 24px;
    color: var(--muted);
    font-size: 17px;
    line-height: 1.85;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 32px;
}

.trust-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px 20px;
    margin-top: 30px;
    color: var(--muted);
    font-size: 13px;
    font-weight: 600;
}

.trust-list li {
    display: inline-flex;
    align-items: center;
    gap: 7px;
}

.trust-list svg {
    width: 16px;
    height: 16px;
    color: var(--green);
}

.hero-note {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 26px;
    color: var(--muted-light);
    font-size: 12px;
}

.hero-note .note-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 5px 10px;
    border-radius: 999px;
    background: var(--amber-soft);
    color: #9a602c;
    font-weight: 700;
}

/* ---------- 首屏演示卡 ---------- */

.hero-demo {
    position: relative;
    padding: 18px 8px;
}

.demo-card {
    position: relative;
    z-index: 2;
    padding: 26px;
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.94);
    border: 1px solid rgba(79, 122, 90, 0.14);
    box-shadow: var(--shadow-lg);
}

.demo-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 20px;
}

.pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.02em;
}

.pill-green {
    background: var(--green-soft);
    color: var(--green-dark);
}

.demo-meta {
    color: var(--muted-light);
    font-size: 12px;
    font-weight: 600;
}

.demo-question {
    font-size: 19px;
    line-height: 1.75;
    font-weight: 600;
    letter-spacing: 0.01em;
}

.demo-question strong {
    color: var(--green-dark);
    font-size: 21px;
    letter-spacing: 0.02em;
}

.quiz-options {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-top: 20px;
}

.quiz-option {
    min-height: 48px;
    padding: 8px 10px;
    border-radius: 14px;
    border: 1px solid var(--line);
    background: #fff;
    color: var(--ink-soft);
    font-size: 15px;
    font-weight: 700;
    transition: border-color 0.2s ease, background 0.2s ease, color 0.2s ease,
        transform 0.2s ease;
}

.quiz-option:hover {
    border-color: var(--green);
    background: var(--green-pale);
    transform: translateY(-1px);
}

.quiz-option.is-right {
    border-color: rgba(79, 122, 90, 0.45);
    background: var(--green-soft);
    color: var(--green-dark);
}

.quiz-option.is-wrong {
    border-color: rgba(194, 90, 77, 0.4);
    background: var(--red-soft);
    color: var(--red);
}

.tutor-bubble {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    padding: 16px;
    border-radius: 18px 18px 18px 6px;
    background: linear-gradient(135deg, #f1f6ef, #eaf2e8);
    border: 1px solid rgba(79, 122, 90, 0.12);
}

.tutor-bubble img {
    width: 38px;
    height: 38px;
    flex-shrink: 0;
    border-radius: 12px;
    object-fit: cover;
    background: #fff;
}

.tutor-name {
    display: block;
    margin-bottom: 3px;
    color: var(--green-dark);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.04em;
}

.tutor-bubble p {
    color: var(--ink-soft);
    font-size: 14px;
    line-height: 1.7;
}

.quick-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 12px;
}

.quick-chips button,
.quick-chips span {
    padding: 7px 12px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: #fff;
    color: var(--muted);
    font-size: 12px;
    font-weight: 600;
}

.quick-chips button:hover {
    border-color: var(--green);
    color: var(--green-dark);
    background: var(--green-pale);
}

.demo-foot {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    margin-top: 20px;
    padding-top: 18px;
    border-top: 1px dashed var(--line);
}

.mastery {
    display: flex;
    align-items: center;
    gap: 9px;
    min-width: 0;
    color: var(--muted);
    font-size: 11px;
    font-weight: 700;
}

.mastery strong {
    color: var(--green-dark);
    font-size: 13px;
}

.mastery-bar {
    width: 86px;
    height: 7px;
    border-radius: 999px;
    background: #e9ede4;
    overflow: hidden;
}

.mastery-bar i {
    display: block;
    width: 62%;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, #7fa36b, #4f7a5a);
    transition: width 0.6s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.badge-soft {
    padding: 6px 10px;
    border-radius: 999px;
    background: var(--amber-soft);
    color: #96602e;
    font-size: 11px;
    font-weight: 700;
    white-space: nowrap;
}

.float-card {
    position: absolute;
    z-index: 3;
    display: flex;
    align-items: center;
    gap: 9px;
    padding: 11px 14px;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.96);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
    color: var(--ink-soft);
    font-size: 12px;
    font-weight: 700;
    animation: floaty 6s ease-in-out infinite;
}

.float-card svg {
    width: 18px;
    height: 18px;
    color: var(--green);
}

.float-card small {
    display: block;
    color: var(--muted-light);
    font-size: 10px;
    font-weight: 600;
}

.float-card-1 {
    top: -6px;
    right: -18px;
    animation-delay: -1.5s;
}

.float-card-2 {
    bottom: -18px;
    left: -20px;
    animation-delay: -3.5s;
}

@keyframes floaty {
    0%,
    100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-8px);
    }
}

/* ---------- 价值条 ---------- */

.value-strip {
    padding: 16px 0 6px;
}

.value-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
    border-radius: var(--radius);
    background: rgba(255, 255, 255, 0.62);
    border: 1px solid var(--line);
    overflow: hidden;
}

.value-item {
    display: flex;
    align-items: center;
    gap: 13px;
    padding: 22px 24px;
    border-right: 1px solid var(--line);
}

.value-item:last-child {
    border-right: 0;
}

.value-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    flex-shrink: 0;
    border-radius: 12px;
    background: var(--green-soft);
    color: var(--green-dark);
}

.value-icon svg {
    width: 20px;
    height: 20px;
}

.value-item strong {
    display: block;
    font-size: 14px;
    font-weight: 800;
}

.value-item span {
    display: block;
    margin-top: 1px;
    color: var(--muted);
    font-size: 12px;
}

/* ---------- 三步 ---------- */

.steps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 22px;
}

.step-card {
    position: relative;
    display: flex;
    flex-direction: column;
    padding: 26px 26px 28px;
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.82);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-sm);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

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

.step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: var(--green-dark);
    color: #fff;
    font-size: 13px;
    font-weight: 800;
}

.step-card h3 {
    margin-top: 18px;
    font-size: 20px;
    line-height: 1.4;
    font-weight: 800;
}

.step-card p {
    margin-top: 8px;
    color: var(--muted);
    font-size: 14px;
    line-height: 1.75;
}

.step-visual {
    order: -1;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 154px;
    margin-bottom: 4px;
    border-radius: 18px;
    background: linear-gradient(145deg, #eef4eb, #f7f2e7);
    border: 1px solid rgba(79, 122, 90, 0.08);
    overflow: hidden;
}

/* 步骤一的手机/上传示意 */
.mini-phone {
    width: 116px;
    padding: 8px;
    border-radius: 18px;
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: 0 12px 28px rgba(43, 64, 48, 0.14);
    transform: rotate(-3deg);
}

.mini-phone-bar {
    width: 36px;
    height: 4px;
    margin: 0 auto 8px;
    border-radius: 999px;
    background: #dfe5da;
}

.mini-upload {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    height: 92px;
    border-radius: 11px;
    border: 1px dashed #a9bca4;
    background: #f6f9f4;
    color: var(--green);
}

.mini-upload svg {
    width: 24px;
    height: 24px;
}

.mini-upload small {
    color: var(--muted);
    font-size: 8px;
    font-weight: 700;
}

/* 步骤二的解析卡 */
.mini-parse {
    width: 190px;
    padding: 12px;
    border-radius: 14px;
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: 0 12px 28px rgba(43, 64, 48, 0.1);
}

.mini-line {
    height: 6px;
    margin-bottom: 6px;
    border-radius: 999px;
    background: #e7ebe2;
}

.mini-line.w70 {
    width: 70%;
}

.mini-line.w50 {
    width: 50%;
}

.mini-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin-top: 9px;
}

.mini-tag {
    padding: 3px 7px;
    border-radius: 999px;
    background: var(--green-soft);
    color: var(--green-dark);
    font-size: 8px;
    font-weight: 700;
}

.mini-tag.amber {
    background: var(--amber-soft);
    color: #95602e;
}

/* 步骤三的对话 */
.mini-chat {
    display: flex;
    flex-direction: column;
    gap: 7px;
    width: 196px;
}

.mini-bubble {
    max-width: 88%;
    padding: 8px 10px;
    border-radius: 12px;
    background: #fff;
    border: 1px solid var(--line);
    color: var(--ink-soft);
    font-size: 9px;
    line-height: 1.5;
    box-shadow: 0 5px 14px rgba(43, 64, 48, 0.05);
}

.mini-bubble.tutor {
    align-self: flex-start;
    border-bottom-left-radius: 4px;
    background: #eaf2e8;
    border-color: rgba(79, 122, 90, 0.14);
}

.mini-bubble.me {
    align-self: flex-end;
    border-bottom-right-radius: 4px;
}

/* ---------- 能力网格 ---------- */

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.feature-card {
    padding: 28px;
    border-radius: var(--radius);
    background: rgba(255, 255, 255, 0.86);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-sm);
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
    border-color: rgba(79, 122, 90, 0.28);
    box-shadow: var(--shadow);
}

.feature-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    margin-bottom: 18px;
    border-radius: 15px;
    background: linear-gradient(145deg, #e9f1e6, #f6f1e5);
    border: 1px solid rgba(79, 122, 90, 0.12);
    color: var(--green-dark);
}

.feature-icon svg {
    width: 23px;
    height: 23px;
}

.feature-card h3 {
    font-size: 17px;
    font-weight: 800;
}

.feature-card p {
    margin-top: 8px;
    color: var(--muted);
    font-size: 13.5px;
    line-height: 1.75;
}

/* ---------- 左右交替功能区 ---------- */

.feature-row {
    display: grid;
    grid-template-columns: minmax(0, 0.94fr) minmax(0, 1.06fr);
    gap: 72px;
    align-items: center;
}

.feature-row.reverse .feature-copy {
    order: 2;
}

.feature-row.reverse .feature-media {
    order: 1;
}

.feature-copy h2 {
    font-size: clamp(28px, 3.3vw, 40px);
    line-height: 1.22;
    letter-spacing: -0.02em;
    font-weight: 800;
}

.feature-copy > p {
    margin-top: 18px;
    color: var(--muted);
    font-size: 15.5px;
    line-height: 1.85;
}

.feature-points {
    display: grid;
    gap: 12px;
    margin-top: 24px;
}

.feature-points li {
    display: flex;
    align-items: flex-start;
    gap: 11px;
    color: var(--ink-soft);
    font-size: 14px;
    font-weight: 600;
}

.feature-points svg {
    width: 19px;
    height: 19px;
    flex-shrink: 0;
    margin-top: 1px;
    color: var(--green);
}

.feature-media {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 430px;
    padding: 34px;
    border-radius: 38px;
    background: radial-gradient(420px 300px at 50% 15%, rgba(255, 255, 255, 0.9), transparent 70%),
        linear-gradient(145deg, #eaf2e7, #f7f1e4);
    border: 1px solid rgba(79, 122, 90, 0.1);
    overflow: hidden;
}

.feature-media::before {
    content: "";
    position: absolute;
    width: 260px;
    height: 260px;
    right: -90px;
    top: -90px;
    border-radius: 50%;
    background: rgba(127, 163, 107, 0.14);
}

.feature-media::after {
    content: "";
    position: absolute;
    width: 180px;
    height: 180px;
    left: -70px;
    bottom: -70px;
    border-radius: 50%;
    background: rgba(201, 130, 69, 0.1);
}

.mock-panel {
    position: relative;
    z-index: 2;
    width: min(100%, 390px);
    padding: 20px;
    border-radius: 22px;
    background: rgba(255, 255, 255, 0.96);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.panel-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding-bottom: 14px;
    border-bottom: 1px solid var(--line);
}

.panel-title {
    display: flex;
    align-items: center;
    gap: 9px;
    font-size: 13px;
    font-weight: 800;
}

.panel-title img {
    width: 26px;
    height: 26px;
    border-radius: 8px;
    object-fit: cover;
    background: #fff;
}

.panel-badge {
    padding: 4px 8px;
    border-radius: 999px;
    background: var(--green-soft);
    color: var(--green-dark);
    font-size: 10px;
    font-weight: 700;
}

.chat-body {
    display: flex;
    flex-direction: column;
    gap: 11px;
    padding: 16px 0 4px;
}

.chat-row {
    display: flex;
    gap: 8px;
    align-items: flex-end;
}

.chat-row.student {
    justify-content: flex-end;
}

.chat-avatar {
    width: 24px;
    height: 24px;
    border-radius: 8px;
    object-fit: cover;
    background: #fff;
    flex-shrink: 0;
}

.chat-bubble {
    max-width: 82%;
    padding: 10px 13px;
    border-radius: 14px;
    background: var(--green-pale);
    border: 1px solid rgba(79, 122, 90, 0.12);
    color: var(--ink-soft);
    font-size: 12.5px;
    line-height: 1.65;
}

.chat-row.student .chat-bubble {
    border-radius: 14px 14px 14px 4px;
    background: #fff;
    border-color: var(--line);
}

.chat-row.tutor .chat-bubble {
    border-radius: 14px 14px 4px 14px;
}

.chat-highlight {
    color: var(--green-dark);
    font-weight: 700;
}

.chat-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 4px;
}

.chat-chips span {
    padding: 5px 9px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: #fff;
    color: var(--muted);
    font-size: 10px;
    font-weight: 600;
}

.chat-input {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 14px;
    padding: 9px 12px;
    border-radius: 12px;
    border: 1px solid var(--line);
    background: #fafbf8;
    color: var(--muted-light);
    font-size: 11px;
}

.chat-input > span:first-child {
    flex: 1;
    min-width: 0;
}

.chat-input .send {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex: 0 0 auto;
    width: 26px;
    height: 26px;
    border-radius: 8px;
    background: var(--green-dark);
    color: #fff;
}

.chat-input .send svg {
    width: 13px;
    height: 13px;
}

/* 复习时间轴 */
.review-panel {
    width: min(100%, 410px);
}

.review-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 20px;
}

.review-count {
    display: flex;
    align-items: baseline;
    gap: 7px;
}

.review-count strong {
    font-size: 30px;
    line-height: 1;
    font-weight: 850;
    color: var(--green-dark);
}

.review-count span {
    color: var(--muted);
    font-size: 12px;
    font-weight: 600;
}

.review-timeline {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 4px;
    margin: 22px 0;
}

.timeline-item {
    position: relative;
    text-align: center;
}

.timeline-item::before {
    content: "";
    position: absolute;
    top: 9px;
    left: -50%;
    width: 100%;
    height: 2px;
    background: #dce4d6;
}

.timeline-item:first-child::before {
    display: none;
}

.timeline-dot {
    position: relative;
    z-index: 1;
    display: block;
    width: 20px;
    height: 20px;
    margin: 0 auto 8px;
    border-radius: 50%;
    background: #fff;
    border: 2px solid #c7d4c1;
}

.timeline-item.done .timeline-dot {
    background: var(--green);
    border-color: var(--green);
}

.timeline-item.done .timeline-dot::after {
    content: "";
    position: absolute;
    inset: 5px;
    border-radius: 50%;
    background: #fff;
}

.timeline-item.today .timeline-dot {
    background: var(--amber);
    border-color: var(--amber);
    box-shadow: 0 0 0 5px rgba(201, 130, 69, 0.16);
}

.timeline-item span {
    color: var(--muted);
    font-size: 10px;
    font-weight: 700;
}

.timeline-item.today span {
    color: #9c642e;
}

.review-list {
    display: grid;
    gap: 8px;
}

.review-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: 12px;
    background: #fafbf8;
    border: 1px solid var(--line);
}

.review-item .subject {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    border-radius: 9px;
    background: var(--green-soft);
    color: var(--green-dark);
    font-size: 10px;
    font-weight: 800;
    flex-shrink: 0;
}

.review-item .review-text {
    min-width: 0;
    flex: 1;
    color: var(--ink-soft);
    font-size: 11.5px;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.review-item .review-tag {
    padding: 3px 7px;
    border-radius: 999px;
    background: var(--amber-soft);
    color: #99622f;
    font-size: 9px;
    font-weight: 700;
    white-space: nowrap;
}

/* 打印试卷示意 */
.paper-panel {
    display: flex;
    flex-direction: column;
    gap: 14px;
    width: min(100%, 400px);
    padding: 0;
    background: transparent;
    border: 0;
    box-shadow: none;
}

.paper {
    position: relative;
    padding: 26px 26px 30px;
    border-radius: 10px;
    background: #fff;
    border: 1px solid #e6e8e1;
    box-shadow: 0 24px 60px rgba(43, 64, 48, 0.16);
}

.paper::before {
    content: "";
    position: absolute;
    top: 0;
    left: 22px;
    right: 22px;
    height: 4px;
    border-radius: 0 0 4px 4px;
    background: var(--green);
}

.paper-title {
    text-align: center;
    font-size: 15px;
    font-weight: 800;
}

.paper-meta {
    display: flex;
    justify-content: space-between;
    gap: 8px;
    margin-top: 8px;
    padding-bottom: 12px;
    border-bottom: 1px solid #eceee7;
    color: var(--muted-light);
    font-size: 8px;
    font-weight: 600;
}

.paper-q {
    margin-top: 15px;
    font-size: 10.5px;
    line-height: 1.8;
    color: var(--ink-soft);
}

.paper-q strong {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    margin-right: 5px;
    border-radius: 50%;
    background: var(--green-soft);
    color: var(--green-dark);
    font-size: 8px;
}

.paper-space {
    height: 56px;
    margin-top: 8px;
    border-radius: 4px;
    border: 1px dashed #e4e8df;
    background: repeating-linear-gradient(180deg, transparent, transparent 13px, #f1f3ee 13px, #f1f3ee 14px);
}

.paper-options {
    display: flex;
    gap: 12px;
    margin-top: 6px;
    color: var(--muted);
    font-size: 9px;
}

.print-settings {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px 14px;
    width: 100%;
    padding: 12px 16px;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.96);
    border: 1px solid var(--line);
    box-shadow: 0 12px 30px rgba(43, 64, 48, 0.1);
}

.print-settings strong {
    grid-column: 1 / -1;
    font-size: 10px;
    font-weight: 800;
}

.setting-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 5px;
    color: var(--muted);
    font-size: 9px;
    font-weight: 600;
    white-space: nowrap;
}

.switch {
    position: relative;
    width: 26px;
    height: 15px;
    border-radius: 999px;
    background: #dfe5da;
}

.switch::after {
    content: "";
    position: absolute;
    top: 2px;
    left: 2px;
    width: 11px;
    height: 11px;
    border-radius: 50%;
    background: #fff;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
    transition: left 0.2s ease;
}

.switch.on {
    background: var(--green);
}

.switch.on::after {
    left: 13px;
}

/* ---------- 适用人群 ---------- */

.audience-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
}

.audience-card {
    padding: 26px 24px;
    border-radius: var(--radius);
    background: rgba(255, 255, 255, 0.8);
    border: 1px solid var(--line);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.audience-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-sm);
}

.audience-emoji {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 46px;
    height: 46px;
    margin-bottom: 16px;
    border-radius: 14px;
    background: var(--green-pale);
    font-size: 22px;
}

.audience-card h3 {
    font-size: 16px;
    font-weight: 800;
}

.audience-card p {
    margin-top: 6px;
    color: var(--muted);
    font-size: 13px;
    line-height: 1.7;
}

/* ---------- FAQ ---------- */

.faq-wrap {
    max-width: 820px;
    margin-inline: auto;
}

.faq-item {
    border-bottom: 1px solid var(--line);
}

.faq-item summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    padding: 22px 4px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    list-style: none;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary .faq-icon {
    position: relative;
    width: 26px;
    height: 26px;
    flex-shrink: 0;
    border-radius: 50%;
    border: 1px solid var(--line-strong);
    background: #fff;
    transition: transform 0.25s ease, background 0.25s ease;
}

.faq-item summary .faq-icon::before,
.faq-item summary .faq-icon::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    width: 10px;
    height: 1.5px;
    border-radius: 2px;
    background: var(--green-dark);
    transform: translate(-50%, -50%);
}

.faq-item summary .faq-icon::after {
    transform: translate(-50%, -50%) rotate(90deg);
    transition: transform 0.25s ease;
}

.faq-item[open] summary .faq-icon {
    background: var(--green-soft);
}

.faq-item[open] summary .faq-icon::after {
    transform: translate(-50%, -50%) rotate(0deg);
}

.faq-answer {
    padding: 0 46px 24px 4px;
    color: var(--muted);
    font-size: 14px;
    line-height: 1.85;
}

.faq-answer a {
    color: var(--green-dark);
    font-weight: 700;
    text-decoration: underline;
    text-underline-offset: 3px;
}

/* ---------- 底部 CTA ---------- */

.cta-band {
    position: relative;
    margin: 40px auto 0;
    padding: 68px 40px;
    border-radius: 36px;
    background: radial-gradient(600px 300px at 85% 15%, rgba(255, 255, 255, 0.16), transparent 60%),
        linear-gradient(135deg, #3f684b, #2c4a36);
    color: #fff;
    text-align: center;
    overflow: hidden;
}

.cta-band::before,
.cta-band::after {
    content: "";
    position: absolute;
    border-radius: 50%;
    border: 1px solid rgba(255, 255, 255, 0.14);
}

.cta-band::before {
    width: 280px;
    height: 280px;
    left: -100px;
    top: -100px;
}

.cta-band::after {
    width: 380px;
    height: 380px;
    right: -140px;
    bottom: -180px;
}

.cta-band h2 {
    position: relative;
    z-index: 1;
    font-size: clamp(28px, 3.4vw, 42px);
    line-height: 1.25;
    font-weight: 800;
    letter-spacing: -0.02em;
}

.cta-band p {
    position: relative;
    z-index: 1;
    max-width: 560px;
    margin: 16px auto 0;
    color: rgba(255, 255, 255, 0.74);
    font-size: 15px;
    line-height: 1.8;
}

.cta-band .btn {
    position: relative;
    z-index: 1;
    margin-top: 28px;
    background: #fff;
    color: var(--green-dark);
    box-shadow: 0 16px 36px rgba(0, 0, 0, 0.18);
}

.cta-band .btn:hover {
    background: #f3f7f1;
}

/* ---------- 页脚 ---------- */

.site-footer {
    margin-top: 90px;
    padding: 58px 0 24px;
    background: #1e3126;
    color: #dfe8db;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 0.7fr 0.7fr 0.9fr;
    gap: 40px;
    padding-bottom: 38px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 11px;
    margin-bottom: 14px;
}

.footer-brand img {
    width: 40px;
    height: 40px;
    border-radius: 12px;
    object-fit: cover;
    background: #fff;
}

.footer-brand strong {
    font-size: 18px;
    font-weight: 800;
    color: #fff;
}

.footer-desc {
    max-width: 300px;
    color: #a9b8ac;
    font-size: 13px;
    line-height: 1.8;
}

.footer-col h3 {
    margin-bottom: 14px;
    color: #fff;
    font-size: 13px;
    font-weight: 800;
    letter-spacing: 0.04em;
}

.footer-col a,
.footer-col span {
    display: block;
    margin-bottom: 9px;
    color: #a9b8ac;
    font-size: 13px;
    transition: color 0.2s ease;
}

.footer-col a:hover {
    color: #fff;
}

.footer-legal {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    padding-top: 22px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #8fa095;
    font-size: 12px;
}

.footer-legal a {
    color: #b9c7bc;
}

.footer-legal a:hover {
    color: #fff;
}

.footer-legal .legal-links {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 18px;
}

.footer-legal .icp {
    white-space: nowrap;
}

/* ---------- 协议 / 隐私页 ---------- */

.legal-header {
    border-bottom: 1px solid var(--line);
    background: rgba(248, 245, 236, 0.9);
    backdrop-filter: blur(12px);
}

.legal-header .header-inner {
    min-height: 72px;
}

.legal-back {
    color: var(--muted);
    font-size: 13px;
    font-weight: 700;
}

.legal-back:hover {
    color: var(--green-dark);
}

.legal-main {
    padding: 56px 0 20px;
}

.legal-card {
    max-width: 860px;
    margin-inline: auto;
    padding: clamp(28px, 5vw, 56px);
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-sm);
}

.legal-card h1 {
    font-size: clamp(28px, 4vw, 38px);
    line-height: 1.3;
    font-weight: 800;
    letter-spacing: -0.02em;
}

.legal-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 18px;
    margin-top: 14px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--line);
    color: var(--muted-light);
    font-size: 12px;
}

.legal-intro {
    margin-top: 24px;
    color: var(--muted);
    font-size: 14px;
    line-height: 1.9;
}

.legal-card h2 {
    margin-top: 36px;
    margin-bottom: 10px;
    font-size: 18px;
    font-weight: 800;
    color: var(--ink);
}

.legal-card h2 .num {
    color: var(--green);
    margin-right: 6px;
}

.legal-card p {
    margin-bottom: 12px;
    color: var(--ink-soft);
    font-size: 14px;
    line-height: 1.9;
}

.legal-card ul {
    margin: 4px 0 14px;
    padding-left: 0;
    display: grid;
    gap: 8px;
}

.legal-card li {
    position: relative;
    padding-left: 18px;
    color: var(--ink-soft);
    font-size: 14px;
    line-height: 1.85;
}

.legal-card li::before {
    content: "";
    position: absolute;
    top: 11px;
    left: 2px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--green);
}

.legal-card a {
    color: var(--green-dark);
    font-weight: 700;
    text-decoration: underline;
    text-underline-offset: 3px;
}

.legal-note {
    margin-top: 32px;
    padding: 18px 20px;
    border-radius: 14px;
    background: var(--green-pale);
    border: 1px solid rgba(79, 122, 90, 0.12);
    color: var(--muted);
    font-size: 13px;
    line-height: 1.8;
}

.legal-footer {
    padding: 26px 0 34px;
    color: var(--muted-light);
    font-size: 12px;
}

.legal-footer .container {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 10px 20px;
}

.legal-footer a {
    color: var(--muted);
}

.legal-footer a:hover {
    color: var(--green-dark);
}

/* ---------- 滚动出现 ---------- */

.js .reveal {
    opacity: 0;
    transform: translateY(22px);
    transition: opacity 0.7s cubic-bezier(0.2, 0.8, 0.2, 1),
        transform 0.7s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.js .reveal.is-visible {
    opacity: 1;
    transform: none;
}

/* ---------- 响应式 ---------- */

@media (max-width: 1080px) {
    .hero-grid {
        gap: 40px;
    }

    .feature-row {
        gap: 44px;
    }

    .footer-grid {
        grid-template-columns: 1.4fr 0.8fr 0.8fr;
    }

    .footer-grid .footer-col:last-child {
        grid-column: 1 / -1;
        display: flex;
        flex-wrap: wrap;
        gap: 8px 24px;
        align-items: center;
    }

    .footer-grid .footer-col:last-child h3 {
        width: 100%;
        margin-bottom: 0;
    }
}

@media (max-width: 960px) {
    .main-nav {
        display: none;
    }

    .nav-toggle {
        display: inline-flex;
    }

    .main-nav.is-open {
        position: fixed;
        inset: 78px 0 auto;
        display: flex;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        margin: 0;
        padding: 12px 24px 20px;
        background: rgba(250, 247, 239, 0.98);
        border-bottom: 1px solid var(--line);
        box-shadow: 0 20px 40px rgba(43, 64, 48, 0.1);
    }

    .main-nav.is-open a {
        padding: 14px 4px;
        border-bottom: 1px solid var(--line);
        font-size: 15px;
    }

    .main-nav.is-open a:last-child {
        border-bottom: 0;
    }

    .main-nav.is-open .nav-login {
        display: block;
        color: var(--green-dark);
    }

    .hero {
        padding-top: 48px;
    }

    .hero-grid {
        grid-template-columns: 1fr;
        gap: 52px;
    }

    .hero-copy {
        max-width: 660px;
    }

    .hero-demo {
        max-width: 560px;
        margin-inline: auto;
        width: 100%;
    }

    .value-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .value-item:nth-child(2) {
        border-right: 0;
    }

    .value-item:nth-child(-n + 2) {
        border-bottom: 1px solid var(--line);
    }

    .steps-grid,
    .feature-grid {
        grid-template-columns: 1fr 1fr;
    }

    .feature-row,
    .feature-row.reverse {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .feature-row.reverse .feature-copy,
    .feature-row.reverse .feature-media {
        order: initial;
    }

    .feature-media {
        min-height: 380px;
        order: 2;
    }

    .feature-copy {
        order: 1;
    }

    .audience-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 680px) {
    .container {
        width: min(100% - 32px, var(--container));
    }

    .header-inner {
        min-height: 68px;
        gap: 12px;
    }

    .brand img {
        width: 40px;
        height: 40px;
        border-radius: 13px;
    }

    .brand-name {
        font-size: 18px;
    }

    .brand-sub {
        display: none;
    }

    .header-actions .btn-ghost {
        display: none;
    }

    .header-actions .btn-primary {
        min-height: 38px;
        padding-inline: 15px;
        font-size: 13px;
    }

    .main-nav.is-open {
        top: 68px;
    }

    .hero {
        padding: 40px 0 26px;
    }

    .hero-copy h1 {
        font-size: clamp(32px, 9.4vw, 42px);
    }

    .hero-copy .lede {
        margin-top: 18px;
        font-size: 15.5px;
    }

    .hero-actions {
        margin-top: 26px;
    }

    .hero-actions .btn {
        width: 100%;
    }

    .trust-list {
        gap: 8px 16px;
        margin-top: 24px;
    }

    .hero-demo {
        padding: 8px 0;
    }

    .demo-card {
        padding: 20px;
        border-radius: 24px;
    }

    .demo-question {
        font-size: 17px;
    }

    .demo-question strong {
        font-size: 18px;
    }

    .quiz-options {
        gap: 7px;
    }

    .quiz-option {
        min-height: 44px;
        font-size: 14px;
    }

    .float-card {
        display: none;
    }

    .section {
        padding: 66px 0;
    }

    .section-head {
        margin-bottom: 34px;
    }

    .section-head h2 {
        font-size: 28px;
    }

    .section-head p {
        font-size: 14.5px;
    }

    .value-grid {
        grid-template-columns: 1fr;
    }

    .value-item {
        border-right: 0;
        border-bottom: 1px solid var(--line);
        padding: 17px 18px;
    }

    .value-item:last-child {
        border-bottom: 0;
    }

    .steps-grid,
    .feature-grid,
    .audience-grid {
        grid-template-columns: 1fr;
    }

    .step-card,
    .feature-card,
    .audience-card {
        padding: 22px;
    }

    .feature-media {
        min-height: 340px;
        padding: 22px 16px;
        border-radius: 28px;
    }

    .mock-panel {
        padding: 16px;
    }

    .paper {
        padding: 22px 18px 26px;
    }

    .cta-band {
        margin-top: 24px;
        padding: 48px 22px;
        border-radius: 28px;
    }

    .site-footer {
        margin-top: 64px;
        padding-top: 44px;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 28px;
    }

    .footer-grid > div:first-child {
        grid-column: 1 / -1;
    }

    .footer-grid .footer-col:last-child {
        grid-column: 1 / -1;
    }

    .footer-legal {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    .legal-main {
        padding-top: 32px;
    }

    .legal-card {
        padding: 24px 20px;
        border-radius: 22px;
    }

    .legal-card h2 {
        margin-top: 28px;
        font-size: 17px;
    }

    .legal-card p,
    .legal-card li {
        font-size: 13.5px;
    }

    .legal-footer .container {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media print {
    .js .reveal {
        opacity: 1 !important;
        transform: none !important;
    }

    .page-bg,
    .site-header,
    .float-card,
    .nav-toggle {
        display: none !important;
    }

    body {
        background: #fff;
    }

    .section {
        padding: 28px 0;
    }

    .feature-media {
        min-height: 0;
    }

    .cta-band {
        color: #fff;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    .js .reveal {
        opacity: 1;
        transform: none;
        transition: none;
    }

    .float-card,
    .btn,
    .step-card,
    .feature-card,
    .audience-card {
        animation: none;
        transition: none;
    }
}