:root {
    --bg-color: #f0f4f8;
    --primary-color: #1a2a3a;
    --text-main: #2c3e50;
    --text-sub: #7f8c8d;
    
    /* 植物主題色 */
    --color-lily: #9b59b6;      /* 睡蓮: 紫色調 */
    --color-lotus: #e91e63;     /* 蓮花: 粉色調 */
    --color-elodea: #27ae60;    /* 水蘊草: 綠色調 */
    --color-hyacinth: #3498db;  /* 布袋蓮: 藍色調 */
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: "PingFang TC", "Microsoft JhengHei", sans-serif; }

body { 
    background-color: var(--bg-color); 
    color: var(--text-main); 
    user-select: none;
    line-height: 1.6;
}

/* 頂部標題區優化 */
.main-header {
    background: linear-gradient(135deg, #1a2a3a 0%, #2c3e50 100%);
    color: white;
    padding: 3.5rem 1rem;
    text-align: center;
    clip-path: ellipse(120% 100% at 50% 0%); /* 圓弧底邊設計 */
}

.main-header h1 { font-size: 1.8rem; letter-spacing: 2px; margin-bottom: 8px; }
.main-header p { font-size: 0.95rem; opacity: 0.8; font-weight: 300; }

.container {
    max-width: 800px;
    margin: -30px auto 0; /* 往上提與標題交疊 */
    padding: 0 20px 40px;
}

.experiment-list {
    display: grid;
    grid-template-columns: 1fr; /* 手機版單欄 */
    gap: 18px;
}

/* 實驗卡片重新設計 */
.experiment-card {
    display: flex;
    align-items: center;
    background: #ffffff;
    padding: 22px;
    border-radius: 20px;
    text-decoration: none;
    color: inherit;
    box-shadow: 0 8px 20px rgba(0,0,0,0.06);
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    position: relative;
    overflow: hidden;
}

/* 側邊裝飾色塊 */
.experiment-card::before {
    content: "";
    position: absolute;
    left: 0; top: 0; bottom: 0;
    width: 8px;
}

.experiment-card:active { transform: scale(0.96); }

/* 各卡片專屬色設定 */
.card-lily { border-left: 8px solid var(--color-lily); }
.card-lotus { border-left: 8px solid var(--color-lotus); }
.card-elodea { border-left: 8px solid var(--color-elodea); }
.card-hyacinth { border-left: 8px solid var(--color-hyacinth); }

.card-icon { 
    font-size: 2.8rem; 
    margin-right: 20px;
    filter: drop-shadow(0 4px 6px rgba(0,0,0,0.1));
}

.card-info h2 { font-size: 1.25rem; color: #34495e; margin-bottom: 4px; }
.card-info p { font-size: 0.88rem; color: var(--text-sub); margin-bottom: 8px; }

/* 植物類別標籤 */
.tag {
    display: inline-block;
    padding: 3px 12px;
    border-radius: 50px;
    font-size: 0.75rem;
    font-weight: bold;
    background: #f0f2f5;
    color: #7f8c8d;
}

.arrow { 
    margin-left: auto; 
    width: 32px; height: 32px; 
    background: #f8f9fa;
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    color: #bdc3c7; font-size: 0.9rem;
}

.main-footer { text-align: center; padding: 40px 20px; color: #95a5a6; font-size: 0.85rem; }

/* 平板與電腦版切換為雙欄 */
@media (min-width: 600px) {
    .experiment-list { grid-template-columns: 1fr 1fr; }
    .main-header { padding: 5rem 1rem; }
}