/* 節氣變化動畫 */
.jieqi-change {
    animation: jieqiChange 1s ease;
}

@keyframes jieqiChange {
    0% { transform: scale(1) rotate(0deg); }
    50% { transform: scale(1.2) rotate(10deg); }
    100% { transform: scale(1) rotate(0deg); }
}

/* 閃回動畫 */
@keyframes flashback {
    0% {
        filter: grayscale(0%) sepia(0%);
        transform: scale(1);
    }
    50% {
        filter: grayscale(50%) sepia(50%);
        transform: scale(1.05);
    }
    100% {
        filter: grayscale(0%) sepia(0%);
        transform: scale(1);
    }
}

.flashback {
    animation: flashback 3s ease;
}

/* 淚水收集動畫 */
@keyframes tearDrop {
    0% {
        transform: translateY(-30px) scale(0.5);
        opacity: 0;
    }
    50% {
        transform: translateY(0) scale(1.2);
        opacity: 1;
    }
    100% {
        transform: translateY(0) scale(1);
        opacity: 0.7;
    }
}

.tear-drop {
    position: absolute;
    color: #5D5CDE;
    font-size: 28px;
    pointer-events: none;
    animation: tearDrop 1.5s ease forwards;
    filter: drop-shadow(0 2px 5px rgba(0,0,0,0.3));
}

/* 淚水滴落特效 */
.watering-effect {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    background: radial-gradient(circle, rgba(165, 164, 255, 0.3) 0%, rgba(93, 92, 222, 0) 70%);
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.5s ease;
    border-radius: 10px;
}

.watering-active .watering-effect {
    opacity: 1;
    animation: waterPulse 2s infinite;
}

@keyframes waterPulse {
    0% { transform: scale(0.95); opacity: 0.7; }
    50% { transform: scale(1.05); opacity: 1; }
    100% { transform: scale(0.95); opacity: 0.7; }
}

/* --- 粒子系統樣式 --- */

#particle-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1; /* 在背景之上，但在 UI 之下 */
    overflow: hidden;
}

.particle {
    position: absolute;
    top: -20px; /* 從頂部上方開始 */
    user-select: none;
    will-change: transform, opacity;
}

/* 春：花瓣 */
.particle-petal {
    color: #FFB7C5;
    opacity: 0.8;
    animation: fall-sway 10s linear infinite;
}

/* 夏：螢火蟲 */
.particle-firefly {
    background: #FFFFA0;
    border-radius: 50%;
    box-shadow: 0 0 10px #FFFFA0, 0 0 20px #FFFFA0;
    top: 100%; /* 從底部升起 */
    animation: float-up 15s ease-in-out infinite;
    opacity: 0;
}

/* 秋：落葉 */
.particle-leaf {
    color: #E26A2C;
    opacity: 0.9;
    animation: fall-rotate 12s linear infinite;
}

/* 冬：雪花 */
.particle-snow {
    color: #FFF;
    opacity: 0.7;
    animation: fall-direct 15s linear infinite;
    text-shadow: 0 0 5px rgba(255,255,255,0.8);
}

/* 粒子動畫關鍵幀 */

/* 飄落並搖擺 (花瓣) */
@keyframes fall-sway {
    0% {
        transform: translateY(0) translateX(0) rotate(0deg);
        opacity: 0;
    }
    10% {
        opacity: 0.8;
    }
    100% {
        transform: translateY(100vh) translateX(100px) rotate(360deg);
        opacity: 0;
    }
}

/* 旋轉飄落 (落葉) */
@keyframes fall-rotate {
    0% {
        transform: translateY(0) translateX(0) rotateX(0) rotateY(0);
        opacity: 0;
    }
    10% {
        opacity: 0.9;
    }
    100% {
        transform: translateY(100vh) translateX(-50px) rotateX(360deg) rotateY(360deg);
        opacity: 0;
    }
}

/* 浮動上升 (螢火蟲) */
@keyframes float-up {
    0% {
        transform: translateY(0) translateX(0) scale(0.8);
        opacity: 0;
        top: 100%;
    }
    10% {
        opacity: 0.6;
    }
    50% {
        transform: translateY(-50vh) translateX(50px) scale(1.2);
        opacity: 0.8;
    }
    90% {
        opacity: 0.6;
    }
    100% {
        transform: translateY(-110vh) translateX(-30px) scale(0.8);
        opacity: 0;
        top: 100%;
    }
}

/* 直接飄落 (雪花) */
@keyframes fall-direct {
    0% {
        transform: translateY(0) translateX(0);
        opacity: 0;
    }
    10% {
        opacity: 0.8;
    }
    90% {
        opacity: 0.8;
    }
    100% {
        transform: translateY(100vh) translateX(20px);
        opacity: 0;
    }
}