/* ============================================
   網球課程網站 — 設計系統
   配色：活力草地綠 + 網球黃點綴
   字體：Noto Sans TC + Inter
   佈局：手機優先 (Mobile First)
   ============================================ */

/* ===== CSS 變數（全站配色與統一數值） ===== */
:root {
    /* 主色系（草地綠） */
    --color-primary: #16A34A;
    --color-primary-light: #DCFCE7;
    --color-primary-dark: #15803D;

    /* 點綴色（網球黃） */
    --color-accent: #EAB308;
    --color-accent-light: #FEF9C3;

    /* 語意色彩 */
    --color-success: #22C55E;
    --color-error: #EF4444;
    --color-warning: #F59E0B;

    /* 中性色（文字、背景、邊框） */
    --color-text: #1F2937;
    --color-text-light: #6B7280;
    --color-bg: #F9FAFB;
    --color-white: #FFFFFF;
    --color-border: #E5E7EB;
    --color-footer-bg: #1F2937;
    --color-footer-text: #9CA3AF;

    /* 字體 */
    --font-sans: 'Inter', 'Noto Sans TC', sans-serif;
    --font-code: 'JetBrains Mono', 'Fira Code', monospace;

    /* 統一圓角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 50px;

    /* 統一陰影 */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);

    /* 統一過渡動畫 */
    --transition: 0.2s ease;
}

/* ===== 全域重設 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

/* ===== 字體階層（手機版基準） ===== */
body {
    font-family: var(--font-sans);
    color: var(--color-text);
    line-height: 1.7;
    letter-spacing: 0.02em;
    background: var(--color-white);
}

h1 {
    font-size: 2.25rem;
    font-weight: 800;
    line-height: 1.2;
}

h2 {
    font-size: 1.75rem;
    font-weight: 700;
    line-height: 1.3;
}

h3 {
    font-size: 1.125rem;
    font-weight: 600;
    line-height: 1.4;
}

h4 {
    font-size: 1rem;
    font-weight: 600;
    line-height: 1.4;
}

/* 小字說明文字 */
small, .text-sm {
    font-size: 0.875rem;
    color: var(--color-text-light);
}

/* 程式碼區塊字體 */
code, pre {
    font-family: var(--font-code);
}

/* ===== 導覽列 ===== */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
    z-index: 1000;
}

.nav-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

/* 品牌旁的圖示 */
.nav-brand i {
    font-size: 1.1rem;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 16px;
}

.nav-links a {
    text-decoration: none;
    color: var(--color-text-light);
    font-weight: 500;
    font-size: 0.875rem;
    transition: color var(--transition);
}

.nav-links a:hover {
    color: var(--color-primary);
}

/* ===== 主視覺區塊 ===== */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 120px 20px 60px;
    gap: 30px;
    /* 主色漸層背景 */
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 50%, #34D399 100%);
    color: var(--color-white);
}

.hero-content {
    max-width: 500px;
    text-align: center;
}

/* 主視覺圖片 */
.hero-image img {
    max-width: 180px;
    /* 讓圖片有彈跳感的動畫 */
    animation: bounce 2s ease-in-out infinite;
}

/* 上下彈跳動畫 */
@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}

.hero h1 {
    margin-bottom: 16px;
    letter-spacing: 2px;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 12px;
    opacity: 0.95;
}

.hero-desc {
    font-size: 1rem;
    margin-bottom: 40px;
    opacity: 0.85;
    line-height: 1.8;
}

/* ===== 通用按鈕 ===== */
.btn-primary {
    display: inline-block;
    padding: 14px 36px;
    background: var(--color-white);
    color: var(--color-primary);
    font-size: 1rem;
    font-weight: 700;
    border-radius: var(--radius-full);
    text-decoration: none;
    transition: transform var(--transition), box-shadow var(--transition);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    background: var(--color-accent-light);
}

/* 大型按鈕（用於報名） */
.btn-large {
    padding: 16px 44px;
    font-size: 1.125rem;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: var(--color-white);
}

.btn-large:hover {
    background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
    color: var(--color-text);
    box-shadow: 0 10px 30px rgba(234, 179, 8, 0.4);
}

/* ===== 區塊標題 ===== */
.section-title {
    text-align: center;
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 40px;
    color: var(--color-text);
}

/* 標題底部裝飾線（使用網球黃點綴） */
.section-title::after {
    content: '';
    display: block;
    width: 48px;
    height: 3px;
    background: var(--color-accent);
    margin: 12px auto 0;
    border-radius: 2px;
}

/* ===== 課程特色 ===== */
.features {
    padding: 60px 20px;
    background: var(--color-bg);
}

.features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    max-width: 1100px;
    margin: 0 auto;
}

.feature-card {
    background: var(--color-white);
    padding: 32px 24px;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition), box-shadow var(--transition);
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

/* Font Awesome 圖示樣式 */
.feature-icon {
    margin-bottom: 16px;
}

.feature-icon i {
    font-size: 2.5rem;
    color: var(--color-primary);
}

.feature-card h3 {
    font-size: 1.125rem;
    margin-bottom: 10px;
    color: var(--color-text);
}

.feature-card p {
    font-size: 0.9375rem;
    color: var(--color-text-light);
    line-height: 1.7;
}

/* ===== 課程內容（時間軸） ===== */
.curriculum {
    padding: 60px 20px;
    background: var(--color-white);
}

.curriculum-timeline {
    max-width: 650px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.timeline-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
}

.timeline-marker {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: var(--color-white);
    font-size: 1.125rem;
    font-weight: 700;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.timeline-content h3 {
    font-size: 1.125rem;
    margin-bottom: 6px;
    color: var(--color-text);
}

.timeline-content p {
    font-size: 0.9375rem;
    color: var(--color-text-light);
    line-height: 1.7;
}

/* ===== 教練介紹 ===== */
.instructor {
    padding: 60px 20px;
    background: var(--color-white);
}

.instructor-card {
    max-width: 600px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 24px;
    background: var(--color-bg);
    border-radius: var(--radius-xl);
    padding: 32px 24px;
    box-shadow: var(--shadow-sm);
}

/* 用字母代替照片的圓形頭像 */
.instructor-avatar {
    flex-shrink: 0;
    width: 90px;
    height: 90px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: var(--color-white);
    font-size: 2.25rem;
    font-weight: 700;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.instructor-name {
    font-size: 1.375rem;
    color: var(--color-text);
    margin-bottom: 4px;
}

.instructor-role {
    font-size: 0.875rem;
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: 12px;
}

.instructor-bio {
    font-size: 0.9375rem;
    color: var(--color-text-light);
    line-height: 1.8;
}

/* ===== 報名資訊 ===== */
.pricing {
    padding: 60px 20px;
    background: var(--color-bg);
}

.pricing-card {
    max-width: 420px;
    margin: 0 auto;
    background: var(--color-white);
    border-radius: var(--radius-xl);
    padding: 36px 24px;
    text-align: center;
    box-shadow: 0 8px 40px rgba(22, 163, 74, 0.1);
    /* 頂部裝飾線 */
    border-top: 4px solid var(--color-primary);
}

.pricing-badge {
    display: inline-block;
    padding: 6px 20px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: var(--color-white);
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    margin-bottom: 24px;
}

.pricing-amount {
    margin-bottom: 28px;
}

.currency {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--color-primary-dark);
    vertical-align: top;
    line-height: 1.8;
}

.price {
    font-size: 3rem;
    font-weight: 800;
    color: var(--color-primary-dark);
}

.pricing-details {
    list-style: none;
    text-align: left;
    margin-bottom: 32px;
}

.pricing-details li {
    padding: 10px 0;
    font-size: 0.9375rem;
    color: var(--color-text-light);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    gap: 10px;
}

/* 報名清單的圖示顏色 */
.pricing-details li i {
    color: var(--color-primary);
    width: 20px;
    text-align: center;
}

.pricing-details li:last-child {
    border-bottom: none;
}

/* ===== 學員心得 ===== */
.testimonials {
    padding: 60px 20px;
    background: var(--color-bg);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    max-width: 1100px;
    margin: 0 auto;
}

.testimonial-card {
    background: var(--color-white);
    padding: 28px 24px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    /* 左側加網球黃裝飾線 */
    border-left: 4px solid var(--color-accent);
    transition: transform var(--transition), box-shadow var(--transition);
}

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

.testimonial-stars {
    color: var(--color-accent);
    font-size: 1.125rem;
    margin-bottom: 12px;
    letter-spacing: 2px;
}

.testimonial-text {
    font-size: 0.9375rem;
    color: var(--color-text);
    line-height: 1.8;
    margin-bottom: 16px;
}

.testimonial-author {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-primary);
}

/* ===== 頁尾 ===== */
.footer {
    padding: 28px 20px;
    text-align: center;
    background: var(--color-footer-bg);
    color: var(--color-footer-text);
    font-size: 0.875rem;
}

/* 頁尾 IG 連結 */
.footer-social {
    margin-bottom: 12px;
}

.footer-ig-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--color-footer-text);
    text-decoration: none;
    font-size: 0.9375rem;
    transition: color var(--transition);
}

.footer-ig-link:hover {
    color: var(--color-accent);
}

.footer-ig-link i {
    font-size: 1.25rem;
}

/* ===== 漢堡選單按鈕（預設隱藏，手機版才顯示） ===== */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.hamburger-line {
    display: block;
    width: 24px;
    height: 2.5px;
    background: var(--color-text);
    border-radius: 2px;
    transition: transform var(--transition), opacity var(--transition);
}

/* 漢堡選單打開時的 X 動畫 */
.hamburger.active .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active .hamburger-line:nth-child(2) {
    opacity: 0;
}

.hamburger.active .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ===== 捲動淡入動畫 ===== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* =============================================
   響應式設計 — 手機優先，由小到大
   ============================================= */

/* ===== 手機版（768px 以下）：漢堡選單 ===== */
@media (max-width: 767px) {
    .hamburger {
        display: flex;
    }

    .nav-links {
        /* 預設隱藏，展開時顯示 */
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(10px);
        padding: 16px 20px;
        box-shadow: var(--shadow-md);
        gap: 8px;
    }

    /* 選單展開狀態 */
    .nav-links.open {
        display: flex;
    }

    .nav-links a {
        display: block;
        padding: 10px 0;
        font-size: 1rem;
        border-bottom: 1px solid var(--color-border);
    }

    .nav-links li:last-child a {
        border-bottom: none;
    }
}

/* ===== 平板（768px 以上） ===== */
@media (min-width: 768px) {
    /* 字體放大 */
    h1 { font-size: 3rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.25rem; }

    .navbar {
        padding: 16px 40px;
    }

    .nav-links {
        gap: 28px;
    }

    .nav-links a {
        font-size: 1rem;
    }

    /* 主視覺改為左右排列 */
    .hero {
        flex-direction: row;
        gap: 60px;
        padding: 120px 40px 80px;
    }

    .hero-image img {
        max-width: 260px;
    }

    .hero-subtitle {
        font-size: 1.375rem;
    }

    .hero-desc {
        font-size: 1.125rem;
    }

    .section-title {
        font-size: 2rem;
        margin-bottom: 48px;
    }

    .features {
        padding: 80px 40px;
    }

    /* 平板版卡片改為兩欄 */
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 28px;
    }

    .feature-card {
        padding: 36px 28px;
    }

    .curriculum {
        padding: 80px 40px;
    }

    .timeline-item {
        gap: 24px;
    }

    .timeline-marker {
        width: 48px;
        height: 48px;
        font-size: 1.25rem;
    }

    /* 教練卡片改為左右排列 */
    .instructor {
        padding: 80px 40px;
    }

    .instructor-card {
        flex-direction: row;
        text-align: left;
        gap: 32px;
        padding: 40px;
    }

    .instructor-avatar {
        width: 100px;
        height: 100px;
        font-size: 2.5rem;
    }

    /* 平板版學員心得改為兩欄 */
    .testimonials {
        padding: 80px 40px;
    }

    .testimonials-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }

    .pricing {
        padding: 80px 40px;
    }

    .pricing-card {
        padding: 48px 40px;
    }

    .price {
        font-size: 4rem;
    }

    .footer {
        padding: 32px 40px;
    }
}

/* ===== 桌面（1200px 以上） ===== */
@media (min-width: 1200px) {
    /* 字體再次放大 */
    h1 { font-size: 4rem; }
    h2 { font-size: 2.25rem; }

    .navbar {
        padding: 16px 60px;
    }

    .nav-links {
        gap: 36px;
    }

    .hero {
        padding: 120px 60px 80px;
    }

    .hero-image img {
        max-width: 300px;
    }

    .section-title {
        font-size: 2.25rem;
    }

    .features {
        padding: 100px 40px;
    }

    /* 桌面版卡片改為三欄 */
    .features-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 32px;
    }

    .feature-card {
        padding: 40px 28px;
    }

    .feature-icon i {
        font-size: 3rem;
    }

    .curriculum {
        padding: 100px 40px;
    }

    .curriculum-timeline {
        gap: 40px;
    }

    .instructor {
        padding: 100px 40px;
    }

    /* 桌面版學員心得改為三欄 */
    .testimonials {
        padding: 100px 40px;
    }

    .testimonials-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 28px;
    }

    .pricing {
        padding: 100px 40px;
    }

    .pricing-card {
        max-width: 440px;
    }
}