body {
    font-family: sans-serif;
    margin: 0;
    color: #333;
    transition: background 0.5s ease-in-out; /* For smooth gradient change if JS modifies it */
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

nav {
    background-color: rgba(255,255,255,0.1);
    padding: 1rem;
    box-shadow: 0 2px 4px rgba(255,255,255,0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    text-decoration: none;
    color: #fff; /* Assuming dark gradient, adjust as needed */
}

nav .button, .button {
    background-color: #007bff;
    color: white;
    padding: 0.5rem 1rem;
    text-decoration: none;
    border-radius: 4px;
    border: none;
    cursor: pointer;
}
nav .button:hover, .button:hover {
    background-color: #0056b3;
}


nav .transparent {
    background-color: transparent;
    padding: 0.5rem 5rem;
    text-decoration: none;
    border: none;
    cursor: move;
}

main {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    text-align: center;
}

.home-content h1 {
    font-size: 2.5rem;
    color: #fff; /* Assuming dark gradient */
    text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
}

.form-container {
    background-color: #f9f9f9;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 400px;
}
.form-container input[type="password"] {
    width: calc(100% - 22px);
    padding: 10px;
    margin-bottom: 1rem;
    border: 1px solid #ddd;
    border-radius: 4px;
}
.form-container .error {
    color: red;
    margin-bottom: 1rem;
}

.summary-container {
    width: 100%;
    max-width: 900px;
}

.app-blocks {
    display: flex;
    justify-content: space-around;
    gap: 2rem;
    margin-top: 2rem;
}

.app-block {
    background-color: #fff;
    border: 1px solid #eee;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    text-align: left;
    width: 100%;
    max-width: 400px;
    margin-bottom: 1rem;
}

.app-block h3 {
    margin-top: 0;
}

/* excel view */
.excel-view-page-container {
    width: 95%;
    max-width: 1400px;
    margin: 1rem auto;
    text-align: left;
}
.excel-list-container {
    margin-bottom: 20px;
    padding: 15px;
    background-color: #f0f0f0;
    border: 1px solid #ddd;
    border-radius: 5px;
    max-height: 200px;
    overflow-y: auto;
}
.excel-list-container h3 {
    margin-top: 0;
    font-size: 1.2em;
}
.excel-list-container ul {
    list-style: none;
    padding: 0;
    margin: 0;
}
.excel-list-container li {
    margin-bottom: 8px;
    padding: 5px;
    border-radius: 3px;
    display: inline-block;
}
.excel-list-container li:hover {
    background-color: #e0e0e0;
}
.excel-list-container li a {
    text-decoration: none;
    color: #007bff;
    cursor: pointer;
    display: block;
}
.excel-list-container li a.active {
    font-weight: bold;
    color: #0056b3;
}

#current-file-display {
    margin-bottom: 10px;
    font-weight: bold;
}
#excel-output {
    overflow-x: auto;
    width: 100%;
    overflow-y: auto;
    border: 1px solid #ccc;
    max-height: 80vh;
    min-height: 300px;
    background-color: #fff;
    font-size: 0.85em;
}

#excel-output .excel-table {
    border-collapse: collapse;
    width: 100%;
    font-size: 14px;
    table-layout: fixed;
}

#excel-output .excel-table td,
#excel-output .excel-table th {
    width: 120px;
    height: 40px;
    padding: 4px 8px;
    border: 1px solid #ccc;
    text-align: left;
    overflow: visible;
    word-wrap: break-word;
    text-overflow: ellipsis;
} 
#excel-output .excel-table thead tr {
    position: -webkit-sticky;
    position: sticky;
    font-weight: bold;
    top: 0;
    left: 0;
    background-color: azure;
    z-index: 100;
}
#sheet-selector,
#subfolder-selector {
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 1em;
    margin-bottom: 10px;
}

a#download {
    margin: 0 20px;
    display: inline-block;
}

@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        gap: 0.5rem;
    }
    .home-content h1 {
        font-size: 1.8rem;
    }
    .app-blocks {
        flex-direction: column;
        align-items: center;
    }
    .app-block {
         width: 90%;
    }
}
/* Nickname Prompt */
#nickname-prompt {
    width: 100%; max-width: 400px; margin: 2rem auto; padding: 20px;
    background-color: #f9f9f9; border: 1px solid #ddd; border-radius: 5px; text-align: center;
}
#nickname-prompt input { padding: 10px; margin-right: 10px; border: 1px solid #ccc; border-radius: 3px; }
#nickname-prompt p.error { color: red; margin-top: 10px; }

/* Main Chat UI Layout */
.chat-page-container {
    display: flex; height: calc(100vh - 120px); width: 95%; max-width: 1200px; margin: 1rem auto; gap: 10px;
}
.chat-main-area { flex-grow: 1; display: flex; flex-direction: column; }
#chat-log {
    flex-grow: 1; border: 1px solid #ccc; padding: 10px; overflow-y: scroll;
    margin-bottom: 10px; background-color: #f9f9f9; font-size: 0.9em;
}
#chat-log p { margin: 3px 0; line-height: 1.4; word-wrap: break-word; }
#chat-log .timestamp { font-size: 0.75em; color: #888; margin-left: 8px; }
#chat-log .nickname { font-weight: bold; }
#chat-log .system-message { font-style: italic; color: #555; }
#chat-log .error-message { font-weight: bold; color: red; }
#chat-log .my-message .nickname { color: #007bff; }
#chat-log .other-message .nickname { color: #28a745; }

.input-area { display: flex; gap: 5px; }
#chat-message-input, #nickname-input { flex-grow: 1; padding: 8px; border: 1px solid #ccc; border-radius: 3px; }

/* Right Sidebar */
.user-list-area { flex-basis: 220px; flex-shrink: 0; border: 1px solid #ccc; padding: 10px; background-color: #f9f9f9; overflow-y: auto; }
.user-list-area h3 { margin-top: 0; font-size: 1.1em; }
.user-list-area ul { list-style: none; padding: 0; margin: 0; }
.user-list-area li { padding: 3px 0; font-size: 0.9em; }

.room-navigator { margin-top: 15px; padding-top: 15px; border-top: 1px solid #ddd; }
.room-navigator h4 { margin-top: 0; margin-bottom: 10px; font-size: 0.9em; color: #555; }
.predefined-rooms .button { display: block; width: 100%; margin-bottom: 5px; text-align: center; box-sizing: border-box; }
.predefined-rooms .button.disabled { background-color: #a9a9a9; cursor: not-allowed; border-color: #a9a9a9;}
.custom-room-joiner { display: flex; gap: 5px; margin-top: 10px; }
.custom-room-joiner input { flex-grow: 1; border: 1px solid #ccc; border-radius: 3px; padding: 0 5px; }
.custom-room-joiner .button { padding: 5px 10px; font-size: 0.8em; }
@media (max-width: 768px) { .chat-page-container { flex-direction: column; } }

.prompt-container {
    width: 100%; max-width: calc(100% - 4rem); margin: 2rem auto; padding: 25px;
    background-color: #f9f9f9; border: 1px solid #ddd; border-radius: 8px; text-align: center;
}
.prompt-container button { margin: 5px; }
.prompt-container .error { color: red; margin-top: 10px; min-height: 1.2em; }