*{
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", sans-serif;
}
/*    font-family: "Noto Serif TC", serif; */
:root{
    --darker-blue : #0b1a37;
    --dark-blue : var(--dark-blue);
    --light-blue : #0e243e;
    --champagne-gold : var(--champagne-gold);
    --accent-rgb : 201, 168, 76;
    --gold-soft : rgba(var(--accent-rgb), 0.15);
    --gold-line : rgba(var(--accent-rgb), 0.35);
    --error-red : #c0392b;
    --error-rgb : 192, 57, 43;
    --text-rgb : 255, 255, 255;
}
html {
    scroll-behavior: smooth;
}
.is_hidden{
    display: none !important;
}
@keyframes fadeInUp{
    from{
        opacity: 0;
        transform: translateY(18px);
    }
    to{
        opacity: 1;
        transform: translateY(0);
    }
}
body {
    background-color: var(--darker-blue);
    padding-top: 63px;

    letter-spacing: 4px;
    font-weight: 400;
}
nav {
    display: flex;
    justify-content: space-between;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(245, 243, 243, 0.85);
    padding: 0.1rem;
    border-bottom: 2px solid var(--champagne-gold);
    opacity: 0.9;
    height: 58px;
    z-index: 9999;
}
.nav_css{
    display: flex;
    flex-direction: row-reverse;
    gap: 15px;
    align-items: center;
}
.nav_css > div{
    font-size: 1.1rem;
    margin-right: 30px;
    cursor: pointer;
    /*手指*/
    /* 【修正】原本是 ".nav_css div"，選到的是「.nav_css 底下所有的 div」，
       不只是最外層的導覽項目，連 .nav_dropdown 裡巢狀的 .nav_dropdown_menu /
       .nav_dropdown_panel / .nav_dropdown_item 這些 div 也全部被吃到這條規則——
       margin-right:30px 讓下拉面板的寬度被撐大 30px，多出一塊看不出來的空白，
       transition 也讓下拉選單裡每個項目的 hover 都跟著套用不必要的過渡動畫。
       改成 ".nav_css > div"（只選直接子層），下拉選單內部的元素就不會再被波及。 */
}

.logo_style {
    margin-left: 10px;
    cursor: pointer;
}
.text_TCTC{
    padding-left: 50px;
    color: rgba(var(--text-rgb), 0.92);
    font-size: 5rem;
    font-weight: 100;
}


/*intro_first_section-----------------------*/

.intro_first_section{
    position: relative;
    z-index: 0;
    height: 100vh;
    width: 100vw;
    background-color: var(--dark-blue);
    box-shadow: 0px 10px 300px black;

}
.intro_first_section_text1_and_img > div{
    opacity: 0;
    animation: fadeInUp 800ms ease forwards;
}
.intro_first_section_text1_and_img > div:nth-child(1){ animation-delay: 0.05s; }
.intro_first_section_text1_and_img > div:nth-child(2){ animation-delay: 0.18s; }
.intro_first_section_text1_and_img > div:nth-child(3){ animation-delay: 0.30s; }
.intro_first_section_text1_and_img > div:nth-child(4){ animation-delay: 0.42s; }
.intro_first_section_text1_and_img > div:nth-child(5){ animation-delay: 0.50s; }
.intro_first_section_text1_and_img > div:nth-child(6){ animation-delay: 0.58s; }


.intro_first_section_text0-0{
    color: var(--champagne-gold);

    margin-top: 90px;
    margin-bottom: 2px;

    letter-spacing: 6px;

    font-family: "Noto Serif TC", serif;  /*宋體*/

}
.intro_first_section_text0-1{
    text-align: center;

    font-family: "Noto Serif TC", serif;  /*宋體*/

    color: #a38941;
    font-size: small;
    margin-top: 0.3rem;

}
.intro_first_section_text1{
    padding-top: 30px;

}
.intro_first_section_text1-1{
    color: rgba(var(--text-rgb), 0.92);
    font-family: "Noto Serif TC", serif;  /*宋體*/
    /* 原本 clamp(2.6rem, 7vw, 5.6rem) 是給「切成兩行、每行7~9字」的短句用的，
       現在改成單行 11 個字，同一個字級會直接撐爆版面、換行換得亂七八糟。
       整體等比縮小，讓 11 個字在正常桌機寬度下能維持單行不換行。 */
    font-size: clamp(1.8rem, 7vw, 4.2rem);

    font-weight: 200;
    letter-spacing: -1px;
    line-height: 1.3;
}
.intro_first_section_text1-2{
    color: var(--champagne-gold);
    font-size: clamp(1.8rem, 5.2vw, 4.2rem);
    font-weight: 280;
}

/* ===== 標語結尾的閃爍游標，呼應「打字」這個主題 =====
   用一個實色矩形模擬打字游標的樣子，不用陰影/光暈，純平面色塊 */
@keyframes cursorBlink{
    0%, 50%{ opacity: 1; }
    50.01%, 100%{ opacity: 0; }
}
.intro_first_section_cursor{
    display: inline-block;
    width: 0.03em;
    height: 0.8em;
    margin-left: 0.18em;
    vertical-align: -0.05em;

    background-color: rgba(var(--text-rgb), 1);

    animation: cursorBlink 1s step-end infinite;
}
/* 【已移除】.intro_first_section_text2-1 / .intro_first_section_text2-1_穩定
   這兩個 class 原本是給第二行標語（更是穩定和專注的結合）用的樣式，
   HTML 那段已經合併成一行新標語，這兩個 class 目前沒有任何元素在用，
   直接刪掉避免之後維護時看到一堆用不到的死程式碼 */
.intro_first_section_text3-1{
    width: 10rem;
    height: 1px;
    background-color: var(--champagne-gold);
    margin-bottom: 60px;
}
.intro_first_section_text4-1{
    
    color: rgba(var(--text-rgb), 0.55);
    font-family: "Noto Serif TC", serif;  /*宋體*/
    margin-top: 2rem;
    margin-bottom: 7rem;
    font-weight: 500;
}
@keyframes ctaGlow{
    0%, 100%{ box-shadow: 0px 0px 4px black, 0px 0px 0px rgba(var(--accent-rgb),0); }
    50%{ box-shadow: 0px 0px 4px black, 0px 0px 14px rgba(var(--accent-rgb),0.45); }
}
.intro_first_section_text5_button{

    background-color: var(--champagne-gold);
    color: var(--dark-blue);
    font-family: "Noto Serif TC", serif;  /*宋體*/

    padding: 1rem 2.3rem;

    font-size: 1.5rem;
    font-weight: 400;

    letter-spacing: 4px;

    box-shadow: 0px 0px 4px black;
    border-radius: 5px;

    transition: all 400ms ease;

    margin-bottom: 3rem;

    animation: ctaGlow 3s ease-in-out infinite;

}


/*intro_second_section-----------------------*/

.intro_second_section{
    position: relative;
    z-index: 1;
    width: 100dvw;
    height: 70vh;
    background-color: var(--light-blue);
    box-shadow: 0px 10px 100px rgb(0, 0, 0, 0.6),
                0px -10px 100px rgb(0, 0, 0, 0.4);
}
.intro_second_section_text1{
    padding-left: 50px;
}
.intro_second_section_text1-1{
    color: var(--champagne-gold);
    font-family: "Noto Serif TC", serif;  /*宋體*/
    font-size: 1.3rem;

    margin-left: 5%;
    padding-top: 50px;
}
.intro_second_section_text1-2{
    font-family: "Noto Serif TC", serif;  /*宋體*/
    font-size: 3rem;
    color: rgba(var(--text-rgb), 0.75);
}
.intro_second_section_text2{
    padding-left: 210px;
    padding-top: 37px;
}
.intro_second_section_text2-1{
    font-size: 1.2rem;
    line-height: 2.1;
    color: rgba(var(--text-rgb), 0.75);
    letter-spacing: 0.2rem;
}

/*intro_third_section-----------------------*/

.intro_third_section_style{
    width: 100vw;
    height: 110vh;
    background-color: var(--dark-blue);
}
.intro_third_section_text1{
    margin-top: 79px;
}
.intro_third_section_text1-1{
    font-size: 1.3rem;
    padding-left: 50px;
    color: var(--champagne-gold);
    font-family: "Noto Serif TC", serif;  /*宋體*/

}
.intro_third_section_text1-2{
    font-family: "Noto Serif TC", serif;  /*宋體*/
    font-size: 3rem;

    color: rgba(var(--text-rgb), 0.75);

    margin-bottom: 3rem;
    padding-left: 50px;
}
.intro_third_section_flex{
    margin: auto;
    
    height: 20rem;
    width: 70rem;
    

    background-color: var(--darker-blue);

    border: 1px solid rgba(var(--accent-rgb), 0.2);

}
.intro_footer {
    margin-bottom: 0px;
    background-color: rgb(245, 243, 243);
    border-top: 2px solid var(--champagne-gold);
    width: 100vw;
    padding: 2.2rem 0 1.6rem;
    box-shadow: 0px -1px 15px rgba(0, 0, 0, 0.5);
    color: black
}

.footer_div{
    display: flex;
    flex-wrap: wrap;
    gap: 80px;
    justify-content: center;
}
.footer_div div{
    margin-top: 40px;
}

.footer_col{
    display: flex;
    flex-direction: column;
    gap: 0.7rem;
    font-weight: 200;
}
.footer_col_title{
    margin: 0;
    font-size: 1.05rem;
    font-weight: 500;
    letter-spacing: 1px;
    color: rgb(34, 18, 48);
}
.footer_link{
    position: relative;
    width: fit-content;

    font-size: 0.8rem;
    color: rgb(34, 18, 48);
    text-decoration: none;

    transition: color 300ms ease;
}
.footer_link::after{
    content: "";
    position: absolute;
    left: 0;
    bottom: -3px;
    width: 0%;
    height: 1px;
    background-color: var(--champagne-gold);
    transition: width 300ms ease;
}

.footer_copyright{
    margin-top: 2rem;
    font-size: 0.8rem;
    color: #555;
    letter-spacing: 1px;
    text-align: center;
}
.start_now_image{
    opacity: 0.85;
    margin-top: 50px;
    cursor: pointer;
    width: 200px;
    box-shadow: 0px -1px 5px black;
}
.intro_first_section_text1_and_img{
    display: flex;
    flex-direction: column;
    align-items: center;
}



/* <a> 標籤預設有底線 要清掉 */
a.si-btn,
a.si-scroll-cta {
    text-decoration: none;
    display: inline-flex;
}
section {
scroll-margin-top: 63px; /* 對齊 nav 高度，避免被遮住 */
position: relative;
}
section:not(.intro_first_section)::before{
    content: "";
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: min(60%, 900px);
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--gold-line), transparent);
}

/* 統一所有 section 的「下一頁」按鈕位置：固定貼在底部置中 */
.si-next-wrap {
position: absolute;
left: 50%;
bottom: 36px;
transform: translateX(-50%);
margin: 0;
padding: 0;
}

.si-scroll-cta {
background-color: transparent;
color: var(--champagne-gold);
font-family: "Noto Serif TC", serif;
padding: 9px 24px;
font-size: 1rem;
font-weight: 400;
letter-spacing: 4px;
border: 1px solid var(--champagne-gold);
border-radius: 2px;
box-shadow: 0px 0px 4px rgba(0, 0, 0, 0.5);
transition: all 300ms ease;
cursor: pointer;
}

.si-scroll-cta:hover {
background-color: var(--champagne-gold);
color: var(--dark-blue);
}

/* ===== 新章節：核心功能（獨立 section，不跟介紹文字混在一起）===== */

.intro_features_section {
width: 100vw;
min-height: 60vh;
background-color: var(--darker-blue);
box-shadow: 0px 10px 100px rgba(0, 0, 0, 0.6),
0px -10px 100px rgba(0, 0, 0, 0.4);
padding-top: 79px;
padding-bottom: 130px;
}

.si-feature_grid {
display: flex;
gap: 30px;
padding-left: 50px;
padding-right: 50px;
margin-top: 20px;
flex-wrap: wrap;
}

.si-feature_card {
flex: 1;
min-width: 220px;
background-color: var(--dark-blue);
border: 1px solid rgba(var(--accent-rgb), 0.2);
padding: 34px 25px 28px;
border-radius: 8px;
position: relative;
transition: all 400ms ease;
cursor: default;
}




.si-feature_card:nth-of-type(1)::after,
.si-feature_card:nth-of-type(2)::after,
.si-feature_card:nth-of-type(3)::after{
    position: absolute;
    top: 16px;
    right: 20px;
    font-family: "Playfair Display", serif;
    font-size: 0.85rem;
    color: var(--champagne-gold);
    opacity: 0.6;
    letter-spacing: 1px;
}


.si-feature_icon {
font-size: 1.5rem;
font-weight: 500;
color: rgba(var(--text-rgb), 0.92);
letter-spacing: 1px;
margin-bottom: 15px;
padding-right: 2rem;
}

.si-feature_title {
color: rgba(var(--text-rgb), 0.92);
font-size: 1.15rem;
font-weight: 500;
margin-bottom: 12px;
letter-spacing: 2px;
}

.si-feature_desc {
color: rgba(var(--text-rgb), 0.68);
font-size: 0.95rem;
line-height: 1.8;
letter-spacing: 1px;
}

/* ===== 第四章節：難度卡片 ===== */

.intro_third_section_flex {
display: flex;
gap: 25px;
background-color: transparent;
border: none;
padding: 0 20px;
}

.si-difficulty_card {
flex: 1;
height: 100%;

background-color: var(--darker-blue);

border: 1px solid rgba(var(--accent-rgb), 0.2);
border-radius: 8px;

padding: 35px 30px;

display: flex;
flex-direction: column;

transition: all 200ms ease;
cursor: pointer;

}



.si-difficulty_level {
color: var(--champagne-gold);

font-size: 0.9rem;

letter-spacing: 3px;
margin-bottom: 10px;
}

.si-difficulty_name {
color: rgba(var(--text-rgb), 0.92);

font-size: 1.8rem;
font-weight: 400;

margin-bottom: 20px;
}

.si-difficulty_desc {
color: rgba(var(--text-rgb), 0.68);
font-size: 0.95rem;
line-height: 1.9;
letter-spacing: 1px;
flex-grow: 1;
}

.si-difficulty_wpm {
color: var(--champagne-gold);
font-size: 0.85rem;
letter-spacing: 2px;
margin-top: 20px;
border-top: 1px solid rgba(var(--accent-rgb), 0.2);
padding-top: 15px;
}

.si-difficulty_card:hover .si-difficulty_wpm{
    border-top-color: rgba(var(--accent-rgb), 0.4);
}