html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    background-color: #f5f5f7;
}
div {
    margin: 0 auto;
}

.one {
    position: absolute; 
    top: 0;
    left: 0;
    z-index: 10;
    width: 100%;
    height: 48px; 
    background-color: rgba(22, 22, 23, 0.8); 
    backdrop-filter: saturate(180%) blur(20px); 
    box-sizing: border-box;
    padding: 0 30px;
}

.top-left {
    float: left;
    height: 48px;
}
.top-left .logo {
    float: left;
    margin-top: 9px;
}
.top-left .logo img {
    width: 30px; 
    height: 30px;
    display: block;
}
.top-left .leader {
    float: left;
    margin-left: 30px;
}
.nav-main {
    list-style: none;
    margin: 0;
    padding: 0;
    height: 48px;
}
.nav-main > li {
    float: left;
    position: relative;
    margin-right: 25px;
}
.nav-main > li > a {
    color: #cccccc;
    text-decoration: none;
    font-size: 12px; 
    letter-spacing: 0.5px;
    line-height: 48px;
    display: block;
    transition: color 0.3s;
}
.nav-main > li > a:hover {
    color: #ffffff;
}

.nav-sub {
    position: absolute;
    top: 48px;
    left: 0;
    background-color: #161617;
    list-style: none;
    margin: 0;
    padding: 8px 0;
    width: 120px;
    display: none;
    box-shadow: 0 8px 30px rgba(0,0,0,0.3);
}
.nav-sub li {
    line-height: 35px;
}
.nav-sub li a {
    color: #86868b;
    text-decoration: none;
    display: block;
    padding-left: 15px;
    font-size: 12px;
}
.nav-sub li a:hover {
    background-color: #2d2d2f;
    color: #ffffff;
}
.nav-main > li:hover .nav-sub {
    display: block;
}

.top-right {
    float: right;
    height: 48px;
}
.top-right .search {
    float: left;
    margin-top: 11px;
    margin-right: 20px;
}
.top-right .search input {
    background: rgba(255, 255, 255, 0.08);
    border: none;
    padding: 4px 12px;
    color: #fff;
    border-radius: 15px 0 0 15px;
    outline: none;
    font-size: 11px;
    width: 120px;
    transition: width 0.3s;
    float: left;
}
.top-right .search input:focus {
    width: 160px;
    background: rgba(255, 255, 255, 0.15);
}
.top-right .search button {
    background: rgba(255, 255, 255, 0.15);
    border: none;
    padding: 4px 10px;
    color: #ccc;
    border-radius: 0 15px 15px 0;
    cursor: pointer;
    font-size: 11px;
    float: left;
}
.top-right .login {
    float: left;
    margin-top: 13px;
}
.top-right .login .btn-login-single {
    color: #fff;
    text-decoration: none;
    font-size: 12px;
    padding: 3px 12px;
    background-color: #0071e3; 
    border-radius: 12px;
    display: block;
    transition: background-color 0.2s;
}
.top-right .login .btn-login-single:hover {
    background-color: #0077ed;
}

.two {
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    position: relative;
    user-select: none;
}
.two .banner {
    width: 100%;
    height: 100%;
    background: #111 url(images/banner.jpg) no-repeat center center;
    background-size: cover;
    position: relative;
}
.two .banner .text {
    color: #f5f5f7;
    font-size: 4.5rem;
    font-weight: 600;
    letter-spacing: 12px;
    text-shadow: 0 4px 20px rgba(0,0,0,0.6);
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%); 
}

.three {
    margin-top: 50px;
    width: 100%;
    height: 460px;
    background-color: #f5f5f7;
}
.three .theme {
    width: 88%;
    max-width: 1150px;
    height: 460px;
}
.three .theme .left {
    width: 48%;
    height: 460px;
    float: left;
}
.three .theme .right {
    width: 48%;
    height: 460px;
    float: right;
}

.three .theme .left .theme1 {
    width: 100%;
    height: 140px;
    margin-bottom: 15px;
    padding: 25px;
    box-sizing: border-box;
    background-color: #ffffff;
    border-radius: 18px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
    transition: box-shadow 0.3s;
}
.three .theme .left .theme1:hover {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.06);
}
.three .theme .left .theme1 h3 {
    margin: 0 0 6px 0;
    font-size: 19px;
    color: #1d1d1f;
    font-weight: 600;
}
.three .theme .left .theme1 p {
    margin: 0;
    font-size: 13px;
    color: #86868b;
    line-height: 1.5;
}
.three .theme .left .theme1 .more-link {
    font-size: 13px;
    color: #0066cc;
    text-decoration: none;
    display: inline-block;
    margin-top: 8px;
}
.three .theme .left .theme1 .more-link:hover {
    text-decoration: underline;
}

/* 右侧大卡片 */
.three .theme .right .theme4 {
    width: 100%;
    height: 450px;
    background-color: #ffffff;
    border-radius: 18px;
    padding: 30px;
    box-sizing: border-box;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
}
.three .theme .right .theme4 h3 {
    margin: 0 0 8px 0;
    color: #1d1d1f;
    font-size: 22px;
}
.three .theme .right .theme4 p {
    font-size: 14px;
    color: #86868b;
    margin: 0 0 20px 0;
}
.three .theme .right .theme4 .image-placeholder {
    width: 100%;
    height: 280px;
    background: #f5f5f7;
    border-radius: 12px;
    overflow: hidden;
}
.three .theme .right .theme4 .image-placeholder img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.four {
    width: 88%;
    max-width: 1150px;
    height: 180px;
    font-size: 0;
    margin: 50px auto;
}
.four .expansion {
    width: 31.33%;
    margin: 0 1%;
    height: 160px;
    display: inline-block;
    vertical-align: top;
    box-sizing: border-box;
    background-color: #ffffff;
    border-radius: 18px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
    transition: transform 0.4s cubic-bezier(0.25, 1, 0.5, 1), box-shadow 0.4s ease;
}
.four .expansion .exp-box {
    padding: 30px 20px;
    text-align: center;
}
.four .expansion .exp-box h4 {
    font-size: 18px;
    margin: 0 0 10px 0;
    color: #1d1d1f;
}
.four .expansion .exp-box p {
    font-size: 13px;
    color: #86868b;
    margin: 0;
}

.four .expansion:hover {
    transform: translateY(-6px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.08);
}

.five {
    width: 100%;
    height: 140px;
    background-color: #f5f5f7;
    border-top: 1px solid #d2d2d7; 
    color: #86868b;
    text-align: center;
    padding-top: 40px;
    box-sizing: border-box;
    font-size: 12px;
    line-height: 2;
}
.five p {
    margin: 0;
}
.five .footer-meta {
    margin-top: 5px;
    color: #b0b0b5;
}


/* 摄影教程 */

.sub-banner {
    width: 100%;
    height: 350px;
    background-color: #1d1d1f; 
    position: relative;
    text-align: center;
    padding-top: 150px;
    box-sizing: border-box;
}
.sub-banner .sub-text {
    color: #f5f5f7;
    font-size: 3rem;
    font-weight: 600;
    letter-spacing: 10px;
}
.sub-banner p {
    color: #86868b;
    font-size: 16px;
    margin-top: 15px;
}


.tutorial-content {
    width: 88%;
    max-width: 1150px;
    margin: 60px auto;
    overflow: hidden;
}

.course-card {
    float: left;
    width: 31.33%;
    margin: 0 1% 40px 1%;
    background-color: #ffffff;
    border-radius: 18px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
    box-sizing: border-box;
    padding: 20px;
    transition: transform 0.4s cubic-bezier(0.25, 1, 0.5, 1), box-shadow 0.4s ease;
}

.course-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.08);
}

.course-card .img-box {
    width: 100%;
    height: 180px;
    background-color: #f5f5f7;
    border-radius: 12px;
    overflow: hidden;
    margin-bottom: 20px;
}
.course-card .img-box img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.course-card h3 {
    margin: 0 0 10px 0;
    font-size: 18px;
    color: #1d1d1f;
    font-weight: 600;
}
.course-card p {
    font-size: 13px;
    color: #86868b;
    line-height: 1.6;
    margin: 0 0 20px 0;
    height: 42px;
    overflow: hidden;
}
.course-card a {
    font-size: 13px;
    color: #0071e3;
    text-decoration: none;
    display: inline-block;
    font-weight: 500;
}
.course-card a:hover {
    text-decoration: underline;
}

/* 影赛活动 */
.event-banner {
    background-color: #1d1d1f; 
}

.event-content {
    width: 88%;
    max-width: 1000px;
    margin: 60px auto;
}

.event-card {
    width: 100%;
    background-color: #ffffff;
    border-radius: 20px;
    margin-bottom: 50px;
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.03);
    overflow: hidden;
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.event-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 16px 40px rgba(0, 0, 0, 0.08);
}

.event-img {
    float: left;
    width: 45%;
    height: 320px;
    background-color: #e5e5ea;
}

.event-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    color: transparent;
}

.event-info {
    float: right;
    width: 55%;
    height: 320px;
    box-sizing: border-box;
    padding: 40px 50px;
    position: relative;
}

.event-card:nth-child(even) .event-img {
    float: right;
}
.event-card:nth-child(even) .event-info {
    float: left;
}

.event-info .status {
    display: inline-block;
    padding: 4px 12px;
    font-size: 11px;
    border-radius: 10px;
    font-weight: 600;
    margin-bottom: 15px;
}
.event-info .status.active {
    background-color: #e3f2fd;
    color: #0071e3; 
}
.event-info .status.ended {
    background-color: #f2f2f7;
    color: #86868b;
}

/* 标题与描述 */
.event-info h3 {
    margin: 0 0 15px 0;
    font-size: 22px;
    color: #1d1d1f;
    font-weight: 600;
}
.event-info p {
    font-size: 14px;
    color: #86868b;
    line-height: 1.6;
    margin: 0 0 30px 0;
}

.event-info .event-meta {
    font-size: 12px;
    color: #1d1d1f;
    margin-bottom: 30px;
}
.event-info .event-meta span {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
}

.event-info .btn-join {
    display: inline-block;
    background-color: #0071e3;
    color: #ffffff;
    text-decoration: none;
    font-size: 14px;
    padding: 10px 24px;
    border-radius: 20px;
    transition: background-color 0.3s;
}
.event-info .btn-join:hover {
    background-color: #0077ed;
}

/* 已结束按钮变为低调灰色 */
.event-info .btn-ended {
    background-color: #1d1d1f;
}
.event-info .btn-ended:hover {
    background-color: #2d2d2f;
}

/* about */
.about-banner {
    background-color: #1d1d1f; 
}

.about-story {
    width: 80%;
    max-width: 1000px;
    margin: 80px auto;
    overflow: hidden;
}

.story-left {
    float: left;
    width: 40%;
    padding-right: 40px;
    box-sizing: border-box;
}

.story-left h3 {
    font-size: 26px;
    color: #1d1d1f;
    line-height: 1.5;
    font-weight: 600;
    margin: 0;
    border-left: 4px solid #0071e3;
    padding-left: 20px;
}

.story-right {
    float: right;
    width: 60%;
    box-sizing: border-box;
}

.story-right p {
    font-size: 15px;
    color: #86868b;
    line-height: 1.8;
    margin: 0 0 20px 0;
}

.story-right strong {
    color: #1d1d1f;
}

.about-values {
    width: 80%;
    max-width: 1000px;
    margin: 0 auto 100px auto;
    overflow: hidden;
    border-top: 1px solid #d2d2d7;
    padding-top: 60px;
}

.value-card {
    float: left;
    width: 31.33%;
    margin: 0 1%;
    text-align: center;
    box-sizing: border-box;
    padding: 20px;
    transition: transform 0.3s ease;
}

.value-card:hover {
    transform: translateY(-5px);
}

.value-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px auto;
    background-color: #f5f5f7;
    border-radius: 50%;
    line-height: 80px;
    font-size: 20px;
    font-weight: 600;
    color: #1d1d1f;
    box-shadow: inset 0 2px 10px rgba(0,0,0,0.05);
}

.value-card h4 {
    font-size: 18px;
    color: #1d1d1f;
    margin: 0 0 10px 0;
}

.value-card p {
    font-size: 13px;
    color: #86868b;
    line-height: 1.6;
    margin: 0;
}