:root {
    --bg-gradient-start: #0f0c29;
    --bg-gradient-mid: #302b63;
    --bg-gradient-end: #24243e;
    --primary-glow-color: #00bcd4;
    --secondary-color: #f0e5d8;
    --text-color: #dcdcdc;
    --card-bg-color: rgba(22, 33, 62, 0.8);
    --adopted-color: #ffc107;
    --paper-bg: #fdf6e3;
    --paper-text: #583c2c;
    --font-family: 'Nanum Myeongjo', serif;
}

body {
    background: linear-gradient(to bottom, var(--bg-gradient-start), var(--bg-gradient-mid), var(--bg-gradient-end));
    color: var(--text-color);
    font-family: var(--font-family);
    margin: 0;
    min-height: 100vh;
    box-sizing: border-box;
    overflow-x: hidden;
}

#app-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    box-sizing: border-box;
    position: relative;
    z-index: 2;
}

header {
    padding: 15px;
    background-color: rgba(0,0,0,0.2);
    border-radius: 15px;
    margin-bottom: 40px;
}

.user-status {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px 15px 20px;
    color: var(--secondary-color);
    font-size: 1.1rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    margin-bottom: 15px;
}

nav {
    display: flex;
    justify-content: center;
    gap: 15px;
}

nav a {
    color: var(--secondary-color);
    text-decoration: none;
    padding: 10px 20px;
    border-radius: 30px;
    transition: background-color 0.3s, color 0.3s;
    border: 1px solid transparent;
}

nav a.active,
nav a:hover {
    background-color: rgba(255,255,255,0.1);
    border-color: var(--primary-glow-color);
}

h2 {
    font-size: 1.8rem;
    color: var(--secondary-color);
    font-weight: normal;
    text-align: center;
    padding-bottom: 10px;
    margin-bottom: 20px;
}

.page {
    display: none;
    flex-direction: column;
    gap: 20px;
    animation: fadeIn 0.8s;
}
.page.active {
    display: flex;
}

/* --- 바다 페이지 --- */
#sea-page {
    position: relative;
    overflow: hidden;
}
#sea-page .sea-content {
    text-align: center;
    padding: 80px 20px;
    position: relative;
    z-index: 2;
}
#sea-page h1 {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 20px;
}
#sea-page p {
    font-size: 1.2rem;
    line-height: 1.7;
    color: var(--text-color);
    margin-bottom: 40px;
}
.sea-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}
.floating-bottle {
    position: absolute;
    width: 40px;
    height: 40px;
    opacity: 0.2;
}
.floating-bottle::before {
    content: '🍾';
    font-size: 30px;
}
.bottle-1 { top: 20%; left: 10%; animation: float-up-down 10s infinite, float-left-right 15s infinite; }
.bottle-2 { top: 50%; left: 80%; animation: float-up-down 8s infinite 2s, float-left-right 12s infinite 2s; }
.bottle-3 { top: 70%; left: 20%; animation: float-up-down 12s infinite 1s, float-left-right 18s infinite 1s; }
.bottle-4 { top: 90%; left: 50%; animation: float-up-down 9s infinite 3s, float-left-right 14s infinite 3s; }

/* --- 버튼 스타일 --- */
.glowing-btn, #get-bottle-from-sea, .back-btn {
    font-family: var(--font-family);
    cursor: pointer;
    border-radius: 50px;
    transition: all 0.3s;
}
.glowing-btn {
    background-color: var(--primary-glow-color);
    color: #fff;
    border: none;
    padding: 15px 30px;
    font-size: 1.2rem;
    box-shadow: 0 0 10px var(--primary-glow-color), 0 0 20px var(--primary-glow-color), 0 0 30px var(--primary-glow-color);
}
.glowing-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px var(--primary-glow-color), 0 0 30px var(--primary-glow-color), 0 0 45px var(--primary-glow-color);
}
.glowing-btn:disabled {
    background-color: #555;
    box-shadow: none;
    cursor: not-allowed;
}

#get-bottle-from-sea {
    background: none;
    border: 1px solid var(--secondary-color);
    color: var(--secondary-color);
    padding: 12px 25px;
    margin-top: 20px;
}
#get-bottle-from-sea:hover {
     background-color: var(--secondary-color);
     color: var(--bg-gradient-start);
}

/* --- 모달 --- */
.modal-container {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.7);
    backdrop-filter: blur(5px);
    display: flex; justify-content: center; align-items: center;
    z-index: 100; animation: fadeIn 0.3s;
}
.modal-content {
    background-color: var(--card-bg-color);
    padding: 40px; border-radius: 15px;
    width: 90%; max-width: 600px;
    position: relative;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    border: 1px solid var(--primary-glow-color);
}
.modal-close-btn {
    position: absolute; top: 15px; right: 20px;
    background: none; border: none;
    color: #fff; font-size: 2rem; cursor: pointer;
}
.modal-content textarea {
    width: 100%; box-sizing: border-box; height: 200px;
    background-color: rgba(0,0,0,0.3); color: var(--text-color);
    border: 1px solid var(--primary-glow-color);
    border-radius: 10px; padding: 15px;
    font-family: var(--font-family); font-size: 1.1rem;
    resize: vertical; margin-bottom: 20px;
}
.modal-content .glowing-btn { width: 100%; }

/* --- 편지함 리스트 --- */
#inbox-container, #outbox-container { display: flex; flex-direction: column; gap: 20px; }
.bottle-card {
    background-color: var(--card-bg-color);
    border-radius: 10px;
    border-left: 3px solid var(--primary-glow-color);
    padding: 25px; cursor: pointer;
    transition: transform 0.3s, box-shadow 0.3s;
}
.bottle-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.3);
}
.bottle-card .worry-snippet {
    font-style: italic; opacity: 0.7;
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.bottle-card .card-status { margin-top: 15px; font-size: 0.9rem; color: var(--adopted-color); }

.adopted-badge {
    color: var(--adopted-color);
    font-size: 0.9rem;
    font-weight: bold;
    margin-left: 10px;
    background: rgba(255, 193, 7, 0.1);
    padding: 3px 8px;
    border-radius: 10px;
    border: 1px solid var(--adopted-color);
}

/* --- 편지 상세 보기 --- */
.bottle-detail {
    background: var(--card-bg-color);
    padding: 30px; border-radius: 15px;
}
.detail-actions-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
}
.back-btn, .secondary-btn, .danger-btn {
    background: none;
    border: 1px solid var(--secondary-color);
    color: var(--secondary-color);
    padding: 8px 15px;
    border-radius: 20px;
    cursor: pointer;
    font-family: var(--font-family);
    transition: all 0.3s;
}
.back-btn:hover, .secondary-btn:hover {
    background-color: var(--secondary-color);
    color: var(--bg-gradient-start);
}
.danger-btn {
    border-color: #e94560;
    color: #e94560;
}
.danger-btn:hover {
    background-color: #e94560;
    color: #fff;
}

.worry-full-text {
    background: var(--paper-bg);
    color: var(--paper-text);
    padding: 30px;
    border-radius: 5px;
    line-height: 1.8;
    font-size: 1.2rem;
    margin-bottom: 30px;
    box-shadow: 2px 2px 8px rgba(0,0,0,0.5);
    border: 1px solid #d4c5a9;
}

/* 답장 입력 폼 스타일 */
.bottle-detail form {
    background-color: rgba(255, 255, 255, 0.08); /* 약간 밝은 투명 배경 */
    padding: 20px;
    border-radius: 10px;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.5); /* 안쪽 그림자 */
    margin-top: 20px;
}

.bottle-detail form textarea {
    width: calc(100% - 30px); /* 패딩 고려 */
    height: 120px;
    background-color: rgba(0, 0, 0, 0.2); /* 폼 배경보다 약간 어둡게 */
    color: var(--text-color);
    border: 1px solid var(--primary-glow-color);
    border-radius: 8px;
    padding: 15px;
    font-family: var(--font-family);
    font-size: 1.05rem;
    resize: vertical;
    margin-bottom: 15px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.3);
    transition: border-color 0.3s, box-shadow 0.3s;
}

.bottle-detail form textarea:focus {
    border-color: var(--secondary-color);
    box-shadow: 0 0 10px var(--secondary-color);
    outline: none;
}

.bottle-detail form .glowing-btn {
    width: 100%;
    font-size: 1.1rem;
    padding: 12px 25px;
}


.replies-section { margin-top: 20px; }
.replies-section h4 {
    color: var(--secondary-color);
    font-weight: normal;
    border-bottom: 1px solid var(--primary-glow-color);
    padding-bottom: 10px;
}
.reply-card {
    background: rgba(255,255,255,0.05);
    padding: 20px; border-radius: 10px;
    margin-top: 15px;
    transition: box-shadow 0.3s;
}
.reply-card p { margin: 0; line-height: 1.7; }
.reply-card .reply-actions { text-align: right; margin-top: 15px; }
.reply-card.adopted {
    border: 1px solid var(--adopted-color);
    box-shadow: 0 0 15px var(--adopted-color);
}
.adopt-btn {
    background: none; border: 1px solid var(--adopted-color);
    color: var(--adopted-color); padding: 8px 15px;
}
.adopt-btn:hover { background-color: var(--adopted-color); color: var(--card-bg-color); }
.adopt-btn[disabled] { cursor: not-allowed; opacity: 0.5; background: #555; border-color: #555; }

/* --- 애니메이션 --- */
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes float-up-down {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}
@keyframes float-left-right {
    0%, 100% { transform: translateX(0); }
    50% { transform: translateX(20px); }
}

@media (max-width: 600px) {
    #app-container { padding: 10px; }
    .user-status { font-size: 1rem; padding: 0 10px 10px 10px; }
    #sea-page h1 { font-size: 2rem; }
    .modal-content { width: 95%; padding: 30px 20px; }
}