/* =========================================
   PHẦN 1: CSS GIAO DIỆN CHUNG
   ========================================= */
:root { --dark-color: #000; }

body {
    margin: 0; padding: 0; font-family: 'Quicksand', sans-serif;
    overflow: hidden; width: 100%; height: 100vh;
    background-color: #ffd1dc; transition: background-color 1.5s ease;
    touch-action: none;
}

body.show-flower { background-color: var(--dark-color); }

.screen-center {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    display: flex; flex-direction: column; justify-content: center; align-items: center;
    text-align: center; z-index: 100; transition: opacity 1s;
}

.hidden { opacity: 0; pointer-events: none; display: none !important; }

/* Intro Styles */
.cat-img { 
    width: 250px; border-radius: 20px;
    margin-bottom: 20px; box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

h1 { color: #d63384; margin-bottom: 30px; font-size: 1.5rem; padding: 0 15px; }

.btn-group { display: flex; gap: 20px; }

button {
    padding: 12px 30px; font-size: 1.1rem; border: none; border-radius: 50px;
    cursor: pointer; font-weight: bold; font-family: 'Quicksand', sans-serif; transition: transform 0.2s;
}

.btn-yes { background-color: #ff6b81; color: white; box-shadow: 0 4px 15px rgba(255, 107, 129, 0.4); transition: transform 0.3s ease;}
.btn-no { background-color: white; color: #555; box-shadow: 0 4px 15px rgba(0,0,0,0.1); }
button:active { transform: scale(0.95); }

.reject-text { font-size: 1.5rem; color: #555; font-weight: bold; }

.heart {
    position: fixed; top: -10px; color: #ff6b81; font-size: 20px;
    animation: fall linear forwards; z-index: 50; text-shadow: 0 0 5px #ff6b81;
}
@keyframes fall { to { transform: translateY(105vh); } }

/* =========================================
   PHẦN 2: THƯ (CÓ THANH KÉO)
   ========================================= */
.letter-card {
    position: absolute; top: 45%; left: 50%; transform: translate(-50%, -50%) scale(0);
    width: 85%; max-width: 350px; padding: 15px 20px;
    background: rgba(255, 255, 255, 0.15); backdrop-filter: blur(8px);
    border-radius: 15px; border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 0 30px rgba(255, 105, 180, 0.3);
    z-index: 200; opacity: 0; transition: all 1s ease-in-out;
    text-align: left; display: flex; flex-direction: column;
}

.letter-card.show { transform: translate(-50%, -50%) scale(1); opacity: 1; }

.letter-content {
    font-family: 'Dancing Script', cursive; font-size: 1.3rem; color: #fff;
    text-shadow: 0 0 4px #ff69b4; line-height: 1.5; white-space: pre-line;
    margin-bottom: 15px; max-height: 45vh; overflow-y: auto; padding-right: 5px;
}

.letter-content::-webkit-scrollbar { width: 4px; }
.letter-content::-webkit-scrollbar-thumb { background: rgba(255, 255, 255, 0.5); border-radius: 4px; }
.letter-content::-webkit-scrollbar-track { background: transparent; }

.btn-read {
    display: block; width: 100%; flex-shrink: 0; margin-top: auto;
    background: linear-gradient(45deg, #ff6b81, #ff9eb5); color: white; padding: 10px;
    border-radius: 20px; text-align: center; box-shadow: 0 4px 10px rgba(255, 107, 129, 0.4); font-size: 1rem;
}

/* =========================================
   PHẦN 3: CSS BÔNG HOA
   ========================================= */
#flower-world {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    display: flex; align-items: flex-end; justify-content: center;
    opacity: 0; transition: opacity 2s ease; z-index: 10;
}

.night {
    position: fixed; left: 50%; top: 0; transform: translateX(-50%); width: 100%; height: 100%; filter: blur(0.1vmin);
    background-image: radial-gradient(ellipse at top, transparent 0%, var(--dark-color)), 
    radial-gradient(ellipse at bottom, var(--dark-color), rgba(145, 233, 255, 0.2)), 
    repeating-linear-gradient(220deg, rgb(0, 0, 0) 0px, rgb(0, 0, 0) 19px, transparent 19px, transparent 22px), 
    repeating-linear-gradient(189deg, rgb(0, 0, 0) 0px, rgb(0, 0, 0) 19px, transparent 19px, transparent 22px), 
    repeating-linear-gradient(148deg, rgb(0, 0, 0) 0px, rgb(0, 0, 0) 19px, transparent 19px, transparent 22px), 
    linear-gradient(90deg, rgb(255, 182, 193), rgb(240, 240, 240)); 
}

/* --- Cấu hình chung cho bó hoa --- */
.flowers {
    position: relative;
    transform-origin: bottom center; 
    margin-bottom: 0;
    transform: scale(1.4); 
}

@media screen and (min-width: 1024px) {
    .flowers {
        transform: scale(0.8); 
        margin-bottom: 5vmin; 
    }
}

.flower { position: absolute; bottom: 10vmin; transform-origin: bottom center; z-index: 10; --fl-speed: 0.8s; }

/* Các class animation hoa (giữ nguyên) */
.flower--1 { animation: moving-flower-1 4s linear infinite; }
.flower--1 .flower__line { height: 70vmin; animation-delay: 0.3s; }
.flower--1 .flower__line__leaf--1 { animation: blooming-leaf-right var(--fl-speed) 1.6s backwards; }
.flower--1 .flower__line__leaf--2 { animation: blooming-leaf-right var(--fl-speed) 1.4s backwards; }
.flower--1 .flower__line__leaf--3 { animation: blooming-leaf-left var(--fl-speed) 1.2s backwards; }
.flower--1 .flower__line__leaf--4 { animation: blooming-leaf-left var(--fl-speed) 1s backwards; }
.flower--1 .flower__line__leaf--5 { animation: blooming-leaf-right var(--fl-speed) 1.8s backwards; }
.flower--1 .flower__line__leaf--6 { animation: blooming-leaf-left var(--fl-speed) 2s backwards; }

.flower--2 { left: 50%; transform: rotate(20deg); animation: moving-flower-2 4s linear infinite; }
.flower--2 .flower__line { height: 60vmin; animation-delay: 0.6s; }
.flower--2 .flower__line__leaf--1 { animation: blooming-leaf-right var(--fl-speed) 1.9s backwards; }
.flower--2 .flower__line__leaf--2 { animation: blooming-leaf-right var(--fl-speed) 1.7s backwards; }
.flower--2 .flower__line__leaf--3 { animation: blooming-leaf-left var(--fl-speed) 1.5s backwards; }
.flower--2 .flower__line__leaf--4 { animation: blooming-leaf-left var(--fl-speed) 1.3s backwards; }

.flower--3 { left: 50%; transform: rotate(-15deg); animation: moving-flower-3 4s linear infinite; }
.flower--3 .flower__line { animation-delay: 0.9s; }
.flower--3 .flower__line__leaf--1 { animation: blooming-leaf-right var(--fl-speed) 2.5s backwards; }
.flower--3 .flower__line__leaf--2 { animation: blooming-leaf-right var(--fl-speed) 2.3s backwards; }
.flower--3 .flower__line__leaf--3 { animation: blooming-leaf-left var(--fl-speed) 2.1s backwards; }
.flower--3 .flower__line__leaf--4 { animation: blooming-leaf-left var(--fl-speed) 1.9s backwards; }

.flower__leafs { position: relative; animation: blooming-flower 2s backwards; }
.flower__leafs--1 { animation-delay: 1.1s; }
.flower__leafs--2 { animation-delay: 1.4s; }
.flower__leafs--3 { animation-delay: 1.7s; }
.flower__leafs::after { content: ""; position: absolute; left: 0; top: 0; transform: translate(-50%, -100%); width: 8vmin; height: 8vmin; background-color: #ffb7c5; filter: blur(10vmin); }
.flower__leaf { position: absolute; bottom: 0; left: 50%; width: 8vmin; height: 11vmin; border-radius: 51% 49% 47% 53%/44% 45% 55% 69%; background-color: #ffb7c5; background-image: linear-gradient(to top, #ffb7c5, #ffe4e1); transform-origin: bottom center; opacity: 0.9; box-shadow: inset 0 0 2vmin rgba(255, 255, 255, 0.5); }
.flower__leaf--1 { transform: translate(-10%, 1%) rotateY(40deg) rotateX(-50deg); }
.flower__leaf--2 { transform: translate(-50%, -4%) rotateX(40deg); }
.flower__leaf--3 { transform: translate(-90%, 0%) rotateY(45deg) rotateX(50deg); }
.flower__leaf--4 { width: 8vmin; height: 8vmin; transform-origin: bottom left; border-radius: 4vmin 10vmin 4vmin 4vmin; transform: translate(0%, 18%) rotateX(70deg) rotate(-43deg); background-image: linear-gradient(to top, #ffb7c5, #ffb7c5); z-index: 1; opacity: 0.8; }

.flower__white-circle { position: absolute; left: -3.5vmin; top: -3vmin; width: 9vmin; height: 4vmin; border-radius: 50%; background-color: #ffffff; }
.flower__white-circle::after { content: ""; position: absolute; left: 50%; top: 45%; transform: translate(-50%, -50%); width: 60%; height: 60%; border-radius: inherit; background-image: repeating-linear-gradient(135deg, rgba(0, 0, 0, 0.03) 0px, rgba(0, 0, 0, 0.03) 1px, transparent 1px, transparent 12px), linear-gradient(90deg, rgb(255, 228, 225), rgb(255, 182, 193)); }

.flower__line { height: 55vmin; width: 1.5vmin; background-image: linear-gradient(to left, rgba(0, 0, 0, 0.2), transparent, rgba(255, 255, 255, 0.2)), linear-gradient(to top, transparent 10%, #ffb7c5, #ff91a4); box-shadow: inset 0 0 2px rgba(0, 0, 0, 0.5); animation: grow-flower-tree 4s backwards; }
.flower__line__leaf { --w: 7vmin; --h: calc(var(--w) + 2vmin); position: absolute; top: 20%; left: 90%; width: var(--w); height: var(--h); border-top-right-radius: var(--h); border-bottom-left-radius: var(--h); background-image: linear-gradient(to top, rgba(255, 182, 193, 0.4), #ffb7c5); }
.flower__line__leaf--1 { transform: rotate(70deg) rotateY(30deg); }
.flower__line__leaf--2 { top: 45%; transform: rotate(70deg) rotateY(30deg); }
.flower__line__leaf--3, .flower__line__leaf--4, .flower__line__leaf--6 { border-top-right-radius: 0; border-bottom-left-radius: 0; border-top-left-radius: var(--h); border-bottom-right-radius: var(--h); left: -460%; top: 12%; transform: rotate(-70deg) rotateY(30deg); }
.flower__line__leaf--4 { top: 40%; }
.flower__line__leaf--5 { top: 0; transform-origin: left; transform: rotate(70deg) rotateY(30deg) scale(0.6); }
.flower__line__leaf--6 { top: -2%; left: -450%; transform-origin: right; transform: rotate(-70deg) rotateY(30deg) scale(0.6); }

.flower__light { position: absolute; bottom: 0vmin; width: 1vmin; height: 1vmin; background-color: rgb(255, 240, 245); border-radius: 50%; filter: blur(0.2vmin); animation: light-ans 4s linear infinite backwards; }
.flower__light:nth-child(odd) { background-color: #ffb7c5; }
.flower__light--1 { left: -2vmin; animation-delay: 1s; }
.flower__light--2 { left: 3vmin; animation-delay: 0.5s; }
.flower__light--3 { left: -6vmin; animation-delay: 0.3s; }
.flower__light--4 { left: 6vmin; animation-delay: 0.9s; }
.flower__light--5 { left: -1vmin; animation-delay: 1.5s; }
.flower__light--6 { left: -4vmin; animation-delay: 3s; }
.flower__light--7 { left: 3vmin; animation-delay: 2s; }
.flower__light--8 { left: -6vmin; animation-delay: 3.5s; }

.grow-ans { animation: grow-ans 2s var(--d) backwards; }
@keyframes grow-ans { 0% { transform: scale(0); opacity: 0; } }

.flower__g-long { --w: 2vmin; --h: 6vmin; --c: #ff91a4; position: absolute; bottom: 10vmin; left: -3vmin; transform-origin: bottom center; transform: rotate(-30deg) rotateY(-20deg); display: flex; flex-direction: column; align-items: flex-end; animation: flower-g-long-ans 3s linear infinite; }
@keyframes flower-g-long-ans { 0%, 100% { transform: rotate(-30deg) rotateY(-20deg); } 50% { transform: rotate(-32deg) rotateY(-20deg); } }
.flower__g-long__top { top: calc(var(--h) * -1); width: calc(var(--w) + 1vmin); height: var(--h); border-top-right-radius: 100%; border-right: 0.7vmin solid var(--c); transform: translate(-0.7vmin, 1vmin); }
.flower__g-long__bottom { width: var(--w); height: 50vmin; transform-origin: bottom center; background-image: linear-gradient(to top, transparent 30%, var(--c)); box-shadow: inset 0 0 2px rgba(0, 0, 0, 0.5); clip-path: polygon(35% 0, 65% 1%, 100% 100%, 0% 100%); }

.flower__g-right { position: absolute; bottom: 6vmin; left: -2vmin; transform-origin: bottom left; transform: rotate(20deg); }
.flower__g-right .leaf { width: 30vmin; height: 50vmin; border-top-left-radius: 100%; border-left: 2vmin solid #ff91a4; background-image: linear-gradient(to bottom, transparent, var(--dark-color) 60%); -webkit-mask-image: linear-gradient(to top, transparent 30%, #ff91a4 60%); }
.flower__g-right--1 { animation: flower-g-right-ans 2.5s linear infinite; }
.flower__g-right--2 { left: 5vmin; transform: rotateY(-180deg); animation: flower-g-right-ans--2 3s linear infinite; }
.flower__g-right--2 .leaf { height: 75vmin; filter: blur(0.3vmin); opacity: 0.8; }
@keyframes flower-g-right-ans { 0%, 100% { transform: rotate(20deg); } 50% { transform: rotate(24deg) rotateX(-20deg); } }
@keyframes flower-g-right-ans--2 { 0%, 100% { transform: rotateY(-180deg) rotate(0deg) rotateX(-20deg); } 50% { transform: rotateY(-180deg) rotate(6deg) rotateX(-20deg); } }

.flower__g-front { position: absolute; bottom: 6vmin; left: 2.5vmin; z-index: 100; transform-origin: bottom center; transform: rotate(-28deg) rotateY(30deg) scale(1.04); animation: flower__g-front-ans 2s linear infinite; }
@keyframes flower__g-front-ans { 0%, 100% { transform: rotate(-28deg) rotateY(30deg) scale(1.04); } 50% { transform: rotate(-35deg) rotateY(40deg) scale(1.04); } }
.flower__g-front__line { width: 0.3vmin; height: 20vmin; background-image: linear-gradient(to top, transparent, #ffb7c5, transparent 100%); position: relative; }
.flower__g-front__leaf-wrapper { position: absolute; top: 0; left: 0; transform-origin: bottom left; transform: rotate(10deg); }
.flower__g-front__leaf-wrapper:nth-child(even) { left: 0vmin; transform: rotateY(-180deg) rotate(5deg); animation: flower__g-front__leaf-left-ans 1s ease-in backwards; }
.flower__g-front__leaf-wrapper:nth-child(odd) { animation: flower__g-front__leaf-ans 1s ease-in backwards; }
.flower__g-front__leaf-wrapper--1 { top: -8vmin; transform: scale(0.7); animation: flower__g-front__leaf-ans 1s 5.5s ease-in backwards !important; }
.flower__g-front__leaf-wrapper--2 { top: -8vmin; transform: rotateY(-180deg) scale(0.7) !important; animation: flower__g-front__leaf-left-ans-2 1s 4.6s ease-in backwards !important; }
.flower__g-front__leaf-wrapper--3 { top: -3vmin; animation: flower__g-front__leaf-ans 1s 4.6s ease-in backwards; }
.flower__g-front__leaf-wrapper--4 { top: -3vmin; transform: rotateY(-180deg) scale(0.9) !important; animation: flower__g-front__leaf-left-ans-2 1s 4.6s ease-in backwards !important; }
@keyframes flower__g-front__leaf-left-ans-2 { 0% { transform: rotateY(-180deg) scale(0); } }
.flower__g-front__leaf-wrapper--5, .flower__g-front__leaf-wrapper--6 { top: 2vmin; }
.flower__g-front__leaf-wrapper--7, .flower__g-front__leaf-wrapper--8 { top: 6.5vmin; }
.flower__g-front__leaf-wrapper--2 { animation-delay: 5.2s !important; }
.flower__g-front__leaf-wrapper--3 { animation-delay: 4.9s !important; }
.flower__g-front__leaf-wrapper--5 { animation-delay: 4.3s !important; }
.flower__g-front__leaf-wrapper--6 { animation-delay: 4.1s !important; }
.flower__g-front__leaf-wrapper--7 { animation-delay: 3.8s !important; }
.flower__g-front__leaf-wrapper--8 { animation-delay: 3.5s !important; }
@keyframes flower__g-front__leaf-ans { 0% { transform: rotate(10deg) scale(0); } }
@keyframes flower__g-front__leaf-left-ans { 0% { transform: rotateY(-180deg) rotate(5deg) scale(0); } }
.flower__g-front__leaf { width: 10vmin; height: 10vmin; border-radius: 100% 0% 0% 100%/100% 100% 0% 0%; box-shadow: inset 0 2px 1vmin hsla(184deg, 97%, 58%, 0.2); background-image: linear-gradient(to bottom left, transparent, var(--dark-color)), linear-gradient(to bottom right, #ffb7c5 50%, transparent 50%, transparent); -webkit-mask-image: linear-gradient(to bottom right, #ffb7c5 50%, transparent 50%, transparent); mask-image: linear-gradient(to bottom right, #ffb7c5 50%, transparent 50%, transparent); }

.flower__g-fr { position: absolute; bottom: -4vmin; left: vmin; transform-origin: bottom left; z-index: 10; animation: flower__g-fr-ans 2s linear infinite; }
@keyframes flower__g-fr-ans { 0%, 100% { transform: rotate(2deg); } 50% { transform: rotate(4deg); } }
.flower__g-fr .leaf { width: 30vmin; height: 50vmin; border-top-left-radius: 100%; border-left: 2vmin solid #ff91a4; -webkit-mask-image: linear-gradient(to top, transparent 25%, #ff91a4 50%); position: relative; z-index: 1; }
.flower__g-fr__leaf { position: absolute; top: 0; left: 0; width: 10vmin; height: 10vmin; border-radius: 100% 0% 0% 100%/100% 100% 0% 0%; box-shadow: inset 0 2px 1vmin hsla(184deg, 97%, 58%, 0.2); background-image: linear-gradient(to bottom left, transparent, var(--dark-color) 98%), linear-gradient(to bottom right, #ffb7c5 45%, transparent 50%, transparent); -webkit-mask-image: linear-gradient(135deg, #ffb7c5 40%, transparent 50%, transparent); }
.flower__g-fr__leaf--1 { left: 20vmin; transform: rotate(45deg); animation: flower__g-fr-leaft-ans-1 0.5s 5.2s linear backwards; }
@keyframes flower__g-fr-leaft-ans-1 { 0% { transform-origin: left; transform: rotate(45deg) scale(0); } }
.flower__g-fr__leaf--2 { left: 12vmin; top: -7vmin; transform: rotate(25deg) rotateY(-180deg); animation: flower__g-fr-leaft-ans-6 0.5s 5s linear backwards; }
.flower__g-fr__leaf--3 { left: 15vmin; top: 6vmin; transform: rotate(55deg); animation: flower__g-fr-leaft-ans-5 0.5s 4.8s linear backwards; }
.flower__g-fr__leaf--4 { left: 6vmin; top: -2vmin; transform: rotate(25deg) rotateY(-180deg); animation: flower__g-fr-leaft-ans-6 0.5s 4.6s linear backwards; }
.flower__g-fr__leaf--5 { left: 10vmin; top: 14vmin; transform: rotate(55deg); animation: flower__g-fr-leaft-ans-5 0.5s 4.4s linear backwards; }
@keyframes flower__g-fr-leaft-ans-5 { 0% { transform-origin: left; transform: rotate(55deg) scale(0); } }
.flower__g-fr__leaf--6 { left: 0vmin; top: 6vmin; transform: rotate(25deg) rotateY(-180deg); animation: flower__g-fr-leaft-ans-6 0.5s 4.2s linear backwards; }
@keyframes flower__g-fr-leaft-ans-6 { 0% { transform-origin: right; transform: rotate(25deg) rotateY(-180deg) scale(0); } }
.flower__g-fr__leaf--7 { left: 5vmin; top: 22vmin; transform: rotate(45deg); animation: flower__g-fr-leaft-ans-7 0.5s 4s linear backwards; }
@keyframes flower__g-fr-leaft-ans-7 { 0% { transform-origin: left; transform: rotate(45deg) scale(0); } }
.flower__g-fr__leaf--8 { left: -4vmin; top: 15vmin; transform: rotate(15deg) rotateY(-180deg); animation: flower__g-fr-leaft-ans-8 0.5s 3.8s linear backwards; }
@keyframes flower__g-fr-leaft-ans-8 { 0% { transform-origin: right; transform: rotate(15deg) rotateY(-180deg) scale(0); } }

@keyframes grow-flower-tree { 0% { height: 0; border-radius: 1vmin; } }
@keyframes blooming-flower { 0% { transform: scale(0); } }
@keyframes moving-flower-1 { 0%, 100% { transform: rotate(2deg); } 50% { transform: rotate(-2deg); } }
@keyframes moving-flower-2 { 0%, 100% { transform: rotate(18deg); } 50% { transform: rotate(14deg); } }
@keyframes moving-flower-3 { 0%, 100% { transform: rotate(-18deg); } 50% { transform: rotate(-20deg) rotateY(-10deg); } }
@keyframes blooming-leaf-right { 0% { transform-origin: left; transform: rotate(70deg) rotateY(30deg) scale(0); } }
@keyframes blooming-leaf-left { 0% { transform-origin: right; transform: rotate(-70deg) rotateY(30deg) scale(0); } }
@keyframes light-ans { 0% { opacity: 0; transform: translateY(0vmin); } 25% { opacity: 1; transform: translateY(-5vmin) translateX(-2vmin); } 50% { opacity: 1; transform: translateY(-15vmin) translateX(2vmin); filter: blur(0.2vmin); } 75% { transform: translateY(-20vmin) translateX(-2vmin); filter: blur(0.2vmin); } 100% { transform: translateY(-30vmin); opacity: 0; filter: blur(1vmin); } }

.paused * { animation-play-state: paused !important; }