/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Proxima Nova', 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

/* 布局 */
.wrapper {
    width: 100%;
    position: relative;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -10px;
}

.col {
    padding: 0 10px;
    flex: 1;
}

.col-xs-10 { flex: 0 0 83.333%; }
.col-xs-2 { flex: 0 0 16.667%; }
.col-sm-3 { flex: 0 0 25%; }
.col-sm-6 { flex: 0 0 50%; }
.col-sm-9 { flex: 0 0 75%; }
.col-md-3 { flex: 0 0 25%; }

/* 工具类 */
.text-centered { text-align: center; }
.flex-centered {
    display: flex;
    align-items: center;
    justify-content: center;
}
.separator-right {
    border-right: 1px solid rgba(150, 152, 153, 0.3);
}

/* 头部导航 */
.header {
    width: 100%;
    height: 70px;
    z-index: 10;
    padding: 15px 0;
    top: 30px;
    left: 0;
    position: absolute;
    transition: top 0.3s ease;
}

.header.is-sticky {
    min-width: 100%;
    top: 0;
    position: fixed;
    background-color: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.05);
}

.logo {
    float: left;
    display: block;
    text-decoration: none;
}

.logo-text {
    font-size: 2rem;
    font-weight: 600;
    color: #ff6b35; /* 橙色主题 */
}

.header.is-sticky .logo-text {
    color: #ff6b35;
}

/* 导航菜单 */
.nav--header {
    float: right;
    margin: 2px 0 0;
}

.nav__items {
    list-style: none;
    display: flex;
    align-items: center;
}

.nav__item {
    margin-left: 20px;
}

.nav__link {
    display: inline-block;
    color: #fff;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.075rem;
    text-transform: uppercase;
    text-decoration: none;
    transition: color 0.3s ease;
}

.nav--header .nav__link {
    margin: 12px 0;
    color: #fff;
}

.nav--header .nav__link:hover,
.nav--header .nav__link:active {
    color: #ffa726; /* 浅橙色 */
}

.header.is-sticky .nav--header .nav__link {
    color: #2196f3; /* 蓝色 */
}

.header.is-sticky .nav--header .nav__link:hover {
    color: #64b5f6; /* 浅蓝色 */
}

/* 按钮 */
.btn {
    display: inline-block;
    border: none;
    border-radius: 3px;
    color: #fff;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.075rem;
    text-transform: uppercase;
    text-decoration: none;
    line-height: 1;
    transition: all 0.3s ease;
    cursor: pointer;
}

.btn--sm {
    padding: 12px 15px 10px;
}

.btn--md {
    padding: 20px 30px 18px;
}

.btn--lg {
    padding: 20px 40px 18px;
}

.btn--cta {
    background-color: #ff6b35; /* 橙色 */
}

.btn--cta:hover {
    background-color: #ff8a65; /* 浅橙色 */
}

.btn--cta:active {
    background-color: #e64a19; /* 深橙色 */
}

.btn--primary {
    background-color: #2196f3; /* 蓝色 */
}

.btn--primary:hover {
    background-color: #64b5f6; /* 浅蓝色 */
}

.btn--primary:active {
    background-color: #1976d2; /* 深蓝色 */
}

/* 移动端菜单按钮 */
.toggle-btn {
    display: none;
    float: right;
    margin: 8px 0 0;
    background: none;
    border: none;
    cursor: pointer;
}

.toggle-btn__icon,
.toggle-btn__icon::after,
.toggle-btn__icon::before {
    width: 30px;
    height: 4px;
    display: block;
    border-radius: 1px;
    position: relative;
    background-color: #fff;
    transition: all 150ms ease-out;
}

.header.is-sticky .toggle-btn__icon,
.header.is-sticky .toggle-btn__icon::after,
.header.is-sticky .toggle-btn__icon::before {
    background-color: #ff6b35;
}

.toggle-btn__icon::after,
.toggle-btn__icon::before {
    content: '';
    top: 0;
    left: 0;
    position: absolute;
}

.toggle-btn__icon::before {
    transform: translate(0, -10px);
}

.toggle-btn__icon::after {
    transform: translate(0, 10px);
}

/* 区域样式 */
.section {
    width: 100%;
    display: flex;
    align-items: center;
    background-color: #f4f4f4;
    position: relative;
}

.section--hero {
    overflow: hidden;
    z-index: 1;
    background: linear-gradient(135deg, #ff6b35 0%, #f57c00 100%); /* 橙色渐变 */
    min-height: 78vh;
}

.section--signup {
    padding: 110px 0 100px;
    background-color: #fff;
}

.section--stats {
    padding: 60px 0;
    background: linear-gradient(135deg, #2196f3 0%, #1976d2 100%); /* 蓝色渐变 */
}

.section__intro {
    padding: 0 0 70px;
}

.section__heading {
    position: relative;
    font-size: 48px;
    font-weight: 700;
    letter-spacing: -0.025rem;
    line-height: 1.1;
    margin-bottom: 40px;
}

.section__heading--ul::after {
    content: '';
    width: 30px;
    height: 1px;
    margin: auto;
    background-color: rgba(150, 152, 153, 0.5);
    right: 0;
    bottom: -20px;
    left: 0;
    position: absolute;
}

.section__sub-heading {
    margin: 40px 0 0;
    font-size: 21px;
    font-weight: 400;
    color: #2c3d4e;
    line-height: 1.5;
}

/* 英雄区域 */
.hero {
    overflow: hidden;
    width: 100%;
}

.hero__content {
    z-index: 3;
    max-width: 500px;
}

.hero__heading {
    font-size: 48px;
    font-weight: 700;
    letter-spacing: -0.025rem;
    line-height: 1.1;
    color: #fff;
    margin-bottom: 30px;
}

.hero__sub-heading {
    font-size: 21px;
    font-weight: 400;
    color: rgba(255, 255, 255, 0.9);
    line-height: 1.5;
    margin-bottom: 40px;
}

.hero__buttons {
    display: flex;
    gap: 20px;
}

/* 注册框 */
.signup-box {
    text-align: center;
    padding: 40px 20px;
}

.signup-box__icon {
    fill: #ff6b35;
    width: 54px;
    height: 54px;
    margin: 0 auto 20px;
}

.signup-box__icon-caption {
    margin: 20px 0 0;
    color: #969899;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.075rem;
    text-transform: uppercase;
    line-height: 1;
}

.signup-box__heading {
    margin: 10px 0 0;
    color: #2c3d4e;
    font-size: 25px;
    font-weight: 700;
    letter-spacing: -0.015rem;
    line-height: 1.2;
    margin-bottom: 20px;
}

.signup-box__description {
    margin: 22px 0 0;
    color: #2c3d4e;
    font-size: 19px;
    font-weight: 400;
    line-height: 1.5;
    margin-bottom: 30px;
}

.signup-box__btn {
    margin: 20px 0 0;
}

/* 统计数据 */
.stats {
    width: 100%;
}

.stats__item {
    text-align: center;
    margin-bottom: 40px;
}

.stats__value {
    font-size: 42px;
    font-weight: 700;
    letter-spacing: 0.01rem;
    color: #fff;
    line-height: 1;
    text-transform: uppercase;
}

.stats__caption {
    margin: 20px 0 0;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.075rem;
    color: #fff;
    line-height: 1;
    text-transform: uppercase;
}

/* 页脚 */
.footer {
    width: 100%;
    z-index: 2;
    padding: 60px 0 40px;
    position: relative;
    background-color: #f4f4f4;
}

.footer-information {
    padding-bottom: 50px;
    max-width: 410px;
    margin: 20px auto;
    border-bottom: 1px solid #e5e5e5;
}

.footer-information p {
    font-size: 16px;
    color: #1b1c1f;
    font-weight: 400;
    line-height: 1.5;
    margin-left: 25px;
}

.footer-information p a {
    color: #2196f3;
    text-decoration: none;
}

.footer-information p a:hover {
    color: #64b5f6;
}

.icon--mail {
    fill: #2196f3;
    width: 40px;
    min-width: 40px;
    height: 28px;
}

.footer__copy {
    color: #aaa;
    font-size: 15px;
    font-weight: 400;
    letter-spacing: 0;
    text-transform: none;
    line-height: 1;
    margin-top: 30px;
}

/* 响应式设计 */
@media only screen and (max-width: 767px) {
    .header {
        top: 0;
    }
    
    .nav--header {
        display: none;
    }
    
    .toggle-btn {
        display: block;
    }
    
    .section--hero {
        min-height: 60vh;
    }
    
    .section--signup {
        padding: 50px 0;
    }
    
    .hero__heading {
        font-size: 36px;
    }
    
    .hero__sub-heading {
        font-size: 18px;
    }
    
    .hero__buttons {
        flex-direction: column;
    }
    
    .section__heading {
        font-size: 36px;
    }
    
    .section__sub-heading {
        font-size: 18px;
    }
    
    .signup-box {
        margin: 40px 0;
    }
    
    .separator-right {
        border-right: none;
        border-bottom: 1px solid rgba(150, 152, 153, 0.3);
        padding-bottom: 40px;
    }
    
    .stats__value {
        font-size: 36px;
    }
    
    .stats__item {
        margin-bottom: 30px;
    }
}

@media only screen and (max-width: 991px) {
    .container {
        padding: 0 15px;
    }
    
    .hero__content {
        max-width: 100%;
        text-align: center;
    }
}