/* ===================================
   About Course Page - Main Stylesheet
   Color Theme: Warm Beige/Brown Palette
   Font: Cormorant Garamond + Nunito Sans
   =================================== */

/* CSS Variables - Design Tokens */
:root {
    --bg-cream: #F5F0EB;
    --bg-warm: #EDE6DD;
    --brown-dark: #8B7355;
    --brown-medium: #A68B6A;
    --brown-light: #C4A882;
    --brown-pale: #D4C4AD;
    --text-primary: #4A3F35;
    --text-secondary: #7D6E5D;
    --text-light: #9B8B7A;
    --border-color: #DDD5CA;
    --accent-brown: #B8956E;
    --card-bg: #FAF8F5;
    --green-muted: #9BA888;
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* ===================================
   Page Entrance Animations
   缓慢、优雅、丝滑的进入动效
   =================================== */

@keyframes pageEnter {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

body {
    font-family: 'Nunito Sans', sans-serif;
    background-color: var(--bg-cream);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    animation: pageEnter 0.8s cubic-bezier(0.22, 1, 0.36, 1) both;
}

/* ===================================
   Top Brand Bar (Black Minimal Style)
   Reference: nestdetail.html detail-top-bar
   =================================== */

.top-nav {
    background: #1a1a1a;
    padding: 10px 0;
    text-align: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    position: relative;
    z-index: 200;
    animation: slideDown 0.6s cubic-bezier(0.22, 1, 0.36, 1) 0.1s both;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.brand-text {
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 11px;
    letter-spacing: 5px;
    color: rgba(255, 250, 245, 0.92);
    margin: 0;
    text-transform: uppercase;
    font-weight: 500;
}



/* ===================================
   Header Navigation (Minimal Design)
   Brand: Course Heart
   =================================== */

.filter-bar {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px 48px;
    background: linear-gradient(180deg, #FAF8F5 0%, #F5F0EB 100%);
    border-bottom: 1px solid rgba(139, 115, 85, 0.08);
    backdrop-filter: blur(10px);
    animation: slideDown 0.6s cubic-bezier(0.22, 1, 0.36, 1) 0.2s both;
}

.back-btn {
    position: absolute;
    left: 48px;
    display: flex;
    align-items: center;
    gap: 6px;
    font-family: 'Nunito Sans', sans-serif;
    font-size: 13px;
    color: #E6A87B;
    text-decoration: none;
    padding: 6px 14px;
    border-radius: 20px;
    transition: all 0.25s ease;
    background: transparent;
    border: 1px solid rgba(230, 168, 123, 0.3);
    cursor: pointer;
}

.back-btn:hover {
    background: rgba(230, 168, 123, 0.1);
    border-color: rgba(230, 168, 123, 0.5);
}

.back-btn svg {
    width: 16px;
    height: 16px;
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    justify-content: center;
}

.brand-heart {
    font-size: 20px;
    color: #C4A882;
    animation: heartbeat 2s ease-in-out infinite;
    display: inline-block;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.brand-text-main {
    font-family: 'Cormorant Garamond', serif;
    font-size: 26px;
    font-weight: 400;
    letter-spacing: 0.1em;
    color: #4A3F35;
    position: relative;
}

.brand-text-main::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg, transparent, #C4A882, transparent);
    opacity: 0.5;
}

/* ===================================
   Main Content Layout
   =================================== */

.main-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem 3rem 4rem;
    animation: fadeInScale 0.8s cubic-bezier(0.22, 1, 0.36, 1) 0.3s both;
}

.content-grid {
    display: grid;
    grid-template-columns: 280px 1fr 480px;
    gap: 2.5rem;
    margin-bottom: 4rem;
}

/* Left Column - Illustration Cards */
.left-column {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    animation: slideUp 0.8s cubic-bezier(0.22, 1, 0.36, 1) 0.4s both;
}

.illustration-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    position: relative;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    overflow: visible;
}

.close-btn {
    position: absolute;
    top: 0.6rem;
    right: 0.6rem;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, #E8D5C4 0%, #C4A882 40%, #8B7355 100%);
    box-shadow: 
        0 2px 4px rgba(0, 0, 0, 0.3),
        inset 0 1px 2px rgba(255, 255, 255, 0.4),
        inset 0 -1px 2px rgba(0, 0, 0, 0.2);
    cursor: default;
    pointer-events: none;
}

.close-btn::before {
    content: '';
    position: absolute;
    top: 3px;
    left: 3px;
    width: 4px;
    height: 4px;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.8) 0%, transparent 100%);
    border-radius: 50%;
}

.close-btn.pin-left {
    top: 0.6rem;
    right: auto;
    left: 0.6rem;
}

.card-image-wrapper {
    flex: 1;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 140px;
}

.card-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 8px;
}

.card-labels {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.label-tags {
    display: flex;
    gap: 0.8rem;
}

.tag {
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.15em;
    color: var(--text-secondary);
    text-transform: uppercase;
}

.email-icon {
    width: 32px;
    height: 32px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

.email-icon:hover {
    border-color: var(--brown-medium);
}

/* Center Column - Text Content */
.center-column {
    padding-top: 1rem;
    animation: slideUp 0.8s cubic-bezier(0.22, 1, 0.36, 1) 0.5s both;
}

.section-header {
    margin-bottom: 2rem;
}

.section-title {
    font-family: 'Cormorant Garamond', serif;
    font-size: 3rem;
    font-weight: 400;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.section-subtitle {
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-light);
}

.divider-line {
    width: 40px;
    height: 2px;
    background-color: var(--brown-pale);
    margin: 1.5rem 0;
}

.content-text {
    font-size: 0.92rem;
    line-height: 1.9;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.info-section {
    margin-top: 2.5rem;
}

.info-item {
    margin-bottom: 1.8rem;
}

.info-label {
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.info-value {
    font-size: 0.88rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

/* Right Column - Main Illustration */
.right-column {
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeInScale 0.8s cubic-bezier(0.22, 1, 0.36, 1) 0.6s both;
}

.main-illustration {
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.illustration-image {
    max-width: 100%;
    height: auto;
    transform: scale(1.2);
}

/* ===================================
   Bottom Feature Cards Section
   Reference: Image-based elegant card design
   =================================== */

.bottom-section {
    margin-top: 4rem;
    padding-bottom: 2rem;
    transform: scale(0.9);
    transform-origin: top center;
    animation: slideUp 1s cubic-bezier(0.22, 1, 0.36, 1) 0.7s both;
}

.bottom-header {
    text-align: center;
    margin-bottom: 3rem;
}

.bottom-title {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 0.35em;
    text-transform: uppercase;
    color: var(--text-light);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.8rem;
}

.feature-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: visible;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 32px rgba(139, 115, 85, 0.12);
}

.feature-image-wrapper {
    width: 140px;
    height: 140px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem 0.8rem;
    position: absolute;

    /* ========== 图片位置调整说明 ==========
     * 使用 top/left 来定位图片位置
     *
     * 【左右移动】修改 left:
     *   - 向左移动: left: -20px;   ← 负数向左
     *   - 向右移动: left: 20px;    ← 正数向右
     *   - 靠左边缘: left: 0;       ← 当前状态
     *
     * 【上下移动】修改 top:
     *   - 向上移动: top: -30px;    ← 负数向上
     *   - 向下移动: top: 30px;     ← 正数向下
     *   - 靠上边缘: top: 0;        ← 当前状态
     *
     * 【组合示例】:
     *   左上角外侧: left: -10px; top: -20px;
     *   右下角内侧: left: auto; right: 10px; bottom: 0;
     */
    top: 0;
    left: 0;

    /* 允许图片超出卡片边界 */
    z-index: 10;
}

.feature-image {
    width: 100%;
    height: auto;
    object-fit: contain;
    filter: sepia(20%) saturate(80%);

    /* ========== 图片位置微调 ==========
     * margin-top: 负值 = 向上移动
     * margin-left: 负值 = 向左移动
     * 可根据需要调整数值
     */
    margin-top: -100px;
    margin-left: -60px;
}

.feature-content-full {
    padding: 2rem 1.8rem 1.5rem;
    display: flex;
    flex-direction: column;
}

.feature-sections {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.3rem;
}

.feature-item {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.item-text {
    font-size: 0.82rem;
    line-height: 1.65;
    color: var(--text-secondary);
}

.feature-footer {
    margin-top: 1.8rem;
    padding-top: 1.2rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;

    /* 确保 footer 占满卡片全宽 */
    width: calc(100% + 3.6rem);  /* 补偿左右 padding (1.8rem * 2) */
    margin-left: -1.8rem;         /* 向左扩展到卡片边缘 */
    padding-left: 1.8rem;         /* 恢复左侧内边距 */
    padding-right: 1.8rem;        /* 恢复右侧内边距 */
}

.footer-label {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-secondary);
}

/* ===================================
   Letter-Style Cards Design
   Three Unique Card Styles
   =================================== */

/* 明信片风格 - Card 1 */
.card-postcard {
    position: relative;
    background: transparent;
    border: none;
    box-shadow: none;
    perspective: 1200px;
    align-self: start;
}

.card-postcard:hover {
    transform: none;
}

.card-postcard:hover .postcard-front {
    transform: translateY(-4px) rotateY(-3deg);
    box-shadow: 
        0 8px 24px rgba(139, 115, 85, 0.15),
        0 4px 8px rgba(139, 115, 85, 0.1);
}

.card-postcard:hover .postcard-back {
    transform: translateY(-4px) rotateY(2deg);
    box-shadow: 
        0 8px 24px rgba(139, 115, 85, 0.15),
        0 4px 8px rgba(139, 115, 85, 0.1);
}

.postcard-front {
    position: relative;
    background:
        linear-gradient(135deg, #FFFEF9 0%, #FFF9F0 100%);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow:
        0 4px 12px rgba(139, 115, 85, 0.1),
        0 2px 4px rgba(139, 115, 85, 0.08),
        inset 0 1px 0 rgba(255, 255, 255, 0.8);
    border: 1px solid rgba(212, 196, 173, 0.4);
    margin-bottom: 1rem;
    transition: transform 0.5s cubic-bezier(0.23, 1, 0.32, 1), box-shadow 0.4s ease;
    transform-style: preserve-3d;
    overflow: visible;
}

.postcard-front::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        repeating-linear-gradient(
            0deg,
            transparent,
            transparent 24px,
            rgba(196, 168, 130, 0.04) 24px,
            rgba(196, 168, 130, 0.04) 25px
        );
    pointer-events: none;
}

.postcard-stamp {
    position: absolute;
    top: 12px;
    right: 12px;
    width: 56px;
    height: 68px;
    background: 
        radial-gradient(ellipse at 30% 30%, rgba(255, 250, 245, 0.8) 0%, transparent 60%),
        linear-gradient(135deg, var(--bg-warm) 0%, var(--brown-pale) 100%);
    border: 2px dashed var(--brown-medium);
    border-radius: 4px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transform: rotate(10deg);
    box-shadow: 
        2px 2px 6px rgba(139, 115, 85, 0.15),
        inset 0 1px 2px rgba(255, 255, 255, 0.5);
    gap: 2px;
}

.stamp-icon {
    font-size: 1.3rem;
    color: var(--text-secondary);
    line-height: 1;
}

.stamp-date {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.6rem;
    font-weight: 600;
    color: var(--brown-dark);
    text-align: center;
    line-height: 1.2;
    letter-spacing: 0.05em;
}

.postmark {
    position: absolute;
    bottom: 12px;
    left: 12px;
    display: flex;
    flex-direction: column;
    gap: 2px;
    opacity: 0.6;
    transform: rotate(-3deg);
}

.postmark-line {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.65rem;
    font-weight: 600;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--brown-medium);
    border: 1.5px solid var(--brown-pale);
    border-radius: 2px;
    padding: 1px 6px;
    line-height: 1.4;
    background: rgba(255, 254, 249, 0.6);
}

.postcard-back {
    background: linear-gradient(135deg, #FFFEF9 0%, #FFF9F0 100%);
    border-radius: 8px;
    padding: 1.2rem 1.5rem 1rem;
    box-shadow:
        0 4px 12px rgba(139, 115, 85, 0.1),
        0 2px 4px rgba(139, 115, 85, 0.08),
        inset 0 1px 0 rgba(255, 255, 255, 0.8);
    border: 1px solid rgba(212, 196, 173, 0.4);
    position: relative;
    transition: transform 0.5s cubic-bezier(0.23, 1, 0.32, 1), box-shadow 0.4s ease;
    transform-style: preserve-3d;
    overflow: visible;
}

.postcard-back::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        repeating-linear-gradient(
            0deg,
            transparent,
            transparent 27px,
            rgba(196, 168, 130, 0.08) 27px,
            rgba(196, 168, 130, 0.08) 28px
        );
    pointer-events: none;
    opacity: 0.5;
}

.postcard-divider {
    position: absolute;
    top: 0;
    left: 50%;
    width: 1px;
    height: 100%;
    background: linear-gradient(
        to bottom,
        transparent 5%,
        rgba(196, 168, 130, 0.2) 20%,
        rgba(196, 168, 130, 0.2) 80%,
        transparent 95%
    );
    transform: translateX(-50%);
    pointer-events: none;
}

.letter-header-mini {
    margin-bottom: 0.8rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid rgba(196, 168, 130, 0.2);
    position: relative;
    z-index: 1;
}

.letter-date-mini {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.85rem;
    font-weight: 400;
    font-style: italic;
    color: var(--text-light);
    letter-spacing: 0.05em;
}

.postcard-quote {
    font-family: 'Cormorant Garamond', serif;
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--text-primary);
    font-weight: 500;
    letter-spacing: 0.03em;
    text-align: center;
    margin-bottom: 0.5rem;
}

.postcard-list {
    font-size: 0.85rem;
    line-height: 1.6;
    color: var(--text-secondary);
    text-align: center;
    letter-spacing: 0.05em;
    margin-bottom: 0;
}

.postcard-poetry {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.95rem;
    line-height: 1.8;
    color: var(--text-primary);
    text-align: center;
    font-style: italic;
    letter-spacing: 0.02em;
}

.feature-divider {
    width: 40px;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--brown-pale), transparent);
    margin: 0.4rem auto;
    opacity: 0.6;
}

/* 信纸风格 - Card 2 */
.card-letter {
    background: linear-gradient(135deg, #FFFEF9 0%, #FFF9F0 50%, #FFFEF9 100%);
    border: 1px solid rgba(212, 196, 173, 0.3);
    box-shadow:
        0 4px 12px rgba(139, 115, 85, 0.1),
        0 2px 4px rgba(139, 115, 85, 0.08);
    position: relative;
    overflow: visible;
    transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1), box-shadow 0.4s ease;
}

.card-letter:hover {
    transform: translateY(-6px);
    box-shadow: 
        0 16px 40px rgba(139, 115, 85, 0.12),
        0 4px 12px rgba(139, 115, 85, 0.08);
}

.card-letter::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        repeating-linear-gradient(
            0deg,
            transparent,
            transparent 31px,
            rgba(196, 168, 130, 0.06) 31px,
            rgba(196, 168, 130, 0.06) 32px
        );
    pointer-events: none;
    opacity: 0.4;
}

.card-letter .feature-content-full {
    position: relative;
    z-index: 1;
}

.wax-seal {
    position: absolute;
    top: -18px;
    right: 24px;
    width: 44px;
    height: 44px;
    background: radial-gradient(circle at 35% 35%, #D4A574 0%, #B8956E 40%, #9A7B5B 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 
        0 3px 8px rgba(139, 115, 85, 0.3),
        inset 0 -2px 4px rgba(0, 0, 0, 0.1),
        inset 0 2px 4px rgba(255, 255, 255, 0.3);
    z-index: 2;
    transform: rotate(-8deg);
    transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1);
}

.card-letter:hover .wax-seal {
    transform: rotate(0deg) scale(1.05);
}

.seal-icon {
    font-size: 1.2rem;
    color: rgba(255, 250, 245, 0.9);
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.2));
}

.card-letter .letter-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid rgba(196, 168, 130, 0.2);
}

.card-letter .letter-date {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.9rem;
    font-weight: 400;
    font-style: italic;
    color: var(--text-secondary);
    letter-spacing: 0.05em;
}

.card-letter .letter-location {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-light);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    position: relative;
    padding-left: 12px;
}

.card-letter .letter-location::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--brown-pale);
}

.card-letter .letter-greeting {
    margin-bottom: 1.5rem;
}

.card-letter .greeting-text {
    font-family: 'Cormorant Garamond', serif;
    font-size: 1.3rem;
    font-weight: 500;
    color: var(--text-primary);
    letter-spacing: 0.02em;
    margin: 0;
}

.card-letter .item-text {
    font-family: 'Cormorant Garamond', serif;
    font-size: 0.95rem;
    line-height: 2;
    text-align: justify;
    letter-spacing: 0.01em;
}

.card-letter .signature-area {
    text-align: right;
    margin-top: 1.5rem;
}

.card-letter .signature-text {
    font-family: 'Cormorant Garamond', serif;
    font-size: 1.1rem;
    font-weight: 600;
    font-style: italic;
    color: var(--text-primary);
    letter-spacing: 0.15em;
    position: relative;
    display: inline-block;
}

.card-letter .signature-text::after {
    content: '';
    position: absolute;
    bottom: -3px;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--brown-pale), transparent);
}

/* 便签风格 - Card 3 */
.card-note {
    background: linear-gradient(135deg, #FFF9F0 0%, #FFFBF5 100%);
    border: 1px solid rgba(212, 196, 173, 0.4);
    box-shadow: 
        0 4px 12px rgba(139, 115, 85, 0.12),
        0 2px 4px rgba(139, 115, 85, 0.08);
    position: relative;
    transform: rotate(-1.5deg);
    transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1), box-shadow 0.4s ease;
    align-self: start;
}

.card-note:hover {
    transform: rotate(0deg) translateY(-6px);
    box-shadow: 
        0 16px 40px rgba(139, 115, 85, 0.14),
        0 4px 12px rgba(139, 115, 85, 0.08);
}

.tape-top {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 28px;
    background: 
        linear-gradient(90deg, 
            rgba(255, 255, 255, 0.1) 0%,
            rgba(255, 255, 255, 0.3) 20%,
            rgba(255, 255, 255, 0.1) 40%,
            rgba(255, 255, 255, 0.2) 60%,
            rgba(255, 255, 255, 0.1) 100%
        ),
        rgba(212, 196, 173, 0.5);
    border-radius: 3px;
    box-shadow: 
        0 1px 3px rgba(139, 115, 85, 0.15),
        inset 0 1px 1px rgba(255, 255, 255, 0.4);
    z-index: 3;
    backdrop-filter: blur(2px);
}

.tape-top::before {
    content: '';
    position: absolute;
    top: 0;
    left: -2px;
    right: -2px;
    bottom: 0;
    background: 
        repeating-linear-gradient(
            90deg,
            transparent,
            transparent 3px,
            rgba(139, 115, 85, 0.03) 3px,
            rgba(139, 115, 85, 0.03) 4px
        );
    border-radius: 3px;
}

.note-decoration {
    position: absolute;
    top: 27px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 4;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    margin: 0;
}

.note-pin {
    font-size: 1.1rem;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
    transition: transform 0.3s ease;
    display: block;
    line-height: 1;
}

.card-note:hover .note-pin {
    transform: translateY(-2px);
}

.card-note .feature-content-full {
    padding: 5.625rem 1.8rem 2.25rem;
    min-height: auto;
}

.card-note .note-text {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.85rem;
    line-height: 1.8;
    text-align: center;
    font-style: italic;
    color: var(--text-primary);
    letter-spacing: 0.03em;
    padding: 0 0.5rem;
}

.card-note .feature-footer {
    justify-content: center;
    border-top: none;
    margin-top: 1.8rem;
    padding-top: 0;
}

.heart-seal {
    font-size: 1.2rem;
    color: #C4A882;
    opacity: 0.8;
    animation: heartbeat 2s ease-in-out infinite;
    filter: drop-shadow(0 2px 6px rgba(196, 168, 130, 0.4));
}

/* ===================================
   Card Entrance Animations
   =================================== */

.cards-grid .feature-card:nth-child(1) {
    animation: cardEnter 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.8s both;
}

.cards-grid .feature-card:nth-child(2) {
    animation: cardEnter 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.95s both;
}

.cards-grid .feature-card:nth-child(3) {
    animation: cardEnter 0.9s cubic-bezier(0.22, 1, 0.36, 1) 1.1s both;
}

@keyframes cardEnter {
    from {
        opacity: 0;
        transform: translateY(50px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* ===================================
   Responsive Design - Media Queries
   =================================== */

@media (max-width: 1200px) {
    .content-grid {
        grid-template-columns: 250px 1fr 380px;
        gap: 2rem;
    }
}

@media (max-width: 992px) {
    .content-grid {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }

    .right-column {
        order: -1;
    }

    .main-illustration {
        max-width: 500px;
        margin: 0 auto;
    }

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

@media (max-width: 768px) {
    .top-nav {
        padding: 0.8rem 1.5rem;
        flex-wrap: wrap;
        gap: 1rem;
    }

    .filter-bar {
        padding: 16px 20px;
    }

    .back-btn {
        left: 20px;
        padding: 5px 12px;
        font-size: 12px;
    }

    .back-btn svg {
        width: 14px;
        height: 14px;
    }

    .brand-text-main {
        font-size: 20px;
    }

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

    .main-container {
        padding: 1.5rem;
    }

    .section-title {
        font-size: 2.2rem;
    }
}

/* ===================================
   Footer Styles
   =================================== */

.detail-footer {
    position: relative;
    z-index: 10;
    text-align: center;
    padding: 24px 20px 32px;

    background: transparent;
}

.detail-footer p {
    font-family: 'PingFang SC', -apple-system, 'Microsoft YaHei', sans-serif;
    font-size: 10px;
    letter-spacing: 1.5px;
    color: #D9B89B;
    margin: 0;
}

/* ===================================
   Accessibility - Reduced Motion Support
   为需要减少动画的用户提供支持
   =================================== */

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    
    body {
        animation: none !important;
    }
    
    .top-nav,
    .filter-bar,
    .main-container,
    .left-column,
    .center-column,
    .right-column,
    .bottom-section,
    .feature-card {
        animation: none !important;
        opacity: 1 !important;
        transform: none !important;
    }
}