:root {
    --bg-color: #e9ecef;
    --app-bg: #ffffff;
    --header-border: #dee2e6;
    --name-color: #868e96;
    --received-bg: #343a40;
    --received-text: #ffffff;
    --sent-bg: #e0f1ff;
    --sent-text: #212529;
    --reply-button-bg: #f8f9fa;
    --reply-button-border: #dee2e6;
    --reply-button-text: #495057;
    --primary-color: #007bff;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

#app {
    width: 100%;
    max-width: 480px;
    height: 100vh;
    max-height: 900px;
    background-color: var(--app-bg);
    border-radius: 8px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    position: relative;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
}

/* ユーティリティ */
.hidden {
    display: none !important;
}

/* --- 選択画面 --- */
#selection-screen {
    display: flex;
    flex-direction: column;
    height: 100%;
}
#selection-header {
    padding: 15px;
    border-bottom: 1px solid var(--header-border);
    background-color: #fb94a7;
}
#selection-header h1 {
    margin: 0;
    font-size: 1.5em;
    color: white;
}
#story-list {
    flex-grow: 1;
    overflow-y: auto;
}
.story-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 15px;
    border-bottom: 1px solid var(--header-border);
    cursor: pointer;
    transition: background-color 0.2s;
}
.story-item:hover {
    background-color: #f8f9fa;
}
.story-item img {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    object-fit: cover;
}
.story-info h2 {
    margin: 0 0 5px 0;
    font-size: 1.1em;
    color: var(--sent-text);
}
.story-info p {
    margin: 0;
    font-size: 0.9em;
    color: var(--name-color);
}


/* --- チャット画面 --- */
#chat-screen {
    display: flex;
    flex-direction: column;
    height: 100%;
}
#chat-header {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 15px;
    border-bottom: 1px solid var(--header-border);
    flex-shrink: 0;
}
#back-button {
    background: none;
    border: none;
    font-size: 1.5em;
    font-weight: bold;
    color: var(--primary-color);
    cursor: pointer;
    padding: 0 10px;
}
#header-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}
#header-name {
    font-weight: bold;
    font-size: 1.1em;
}
#message-container {
    flex-grow: 1;
    overflow-y: auto;
    padding: 15px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.message-row {
    display: flex;
    gap: 10px;
    max-width: 85%;
    align-items: flex-start;
}
.message-row.sent { align-self: flex-end; }
.message-row.received { align-self: flex-start; }

/* ★修正: チャット内のアイコンサイズを明示的に指定 */
#message-container .icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    flex-shrink: 0;
}

.message-content { display: flex; flex-direction: column; gap: 5px; }
.character-name { font-size: 0.9em; color: var(--name-color); padding-left: 5px; }
.message-bubble { padding: 10px 15px; border-radius: 18px; line-height: 1.5; word-break: break-word; }
.received .message-bubble { background-color: var(--received-bg); color: var(--received-text); border-top-left-radius: 5px; }
.sent .message-bubble { background-color: var(--sent-bg); color: var(--sent-text); border-top-right-radius: 5px; }
.reply-container { align-self: center; width: 100%; margin-top: 10px; }
.reply-title { font-size: 0.9em; color: var(--name-color); margin-bottom: 10px; padding-left: 10px; border-left: 3px solid var(--name-color); }
.reply-options-wrapper { display: flex; flex-direction: column; gap: 10px; }
.reply-button { width: 100%; background-color: var(--reply-button-bg); border: 1px solid var(--reply-button-border); border-radius: 10px; padding: 15px; font-size: 1em; color: var(--reply-button-text); cursor: pointer; text-align: center; }
.typing-indicator span { display: inline-block; width: 8px; height: 8px; border-radius: 50%; background-color: #aaa; margin: 0 2px; animation: typing 1.2s infinite ease-in-out; }
.typing-indicator span:nth-child(2) { animation-delay: 0.2s; }
.typing-indicator span:nth-child(3) { animation-delay: 0.4s; }
@keyframes typing { 0%, 80%, 100% { opacity: 0.2; } 40% { opacity: 1; } }