:root {
    --bg: #f0f2f5;
    --surface: #ffffff;
    --text: #1f2937;
    --muted: #475569;
    --number-bg: #4a90e2;
    --button-bg: #50e3c2;
    --button-hover: #45c4a8;
    --border: #dbe4ee;
}

body.dark {
    --bg: #0f172a;
    --surface: #111827;
    --text: #f8fafc;
    --muted: #cbd5e1;
    --number-bg: #2563eb;
    --button-bg: #0ea5e9;
    --button-hover: #0284c7;
    --border: #334155;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    background-color: var(--bg);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    transition: background-color 0.25s ease;
}

.container {
    background-color: var(--surface);
    padding: 32px;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    width: min(980px, 100%);
    transition: background-color 0.25s ease;
}

.top-bar {
    align-items: center;
    display: flex;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 20px;
}

h1 {
    color: var(--text);
    margin: 0;
    font-size: 1.8em;
}

h2 {
    color: var(--text);
    margin: 0;
    font-size: 1.25rem;
}

#theme-toggle {
    border: 1px solid var(--border);
    border-radius: 10px;
    background: transparent;
    color: var(--text);
    padding: 10px 14px;
    cursor: pointer;
}

.numbers {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
}

.number {
    width: 50px;
    height: 50px;
    background-color: var(--number-bg);
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5em;
    font-weight: bold;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease, background-color 0.3s ease;
}

#generate {
    background-color: var(--button-bg);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 10px;
    font-size: 1.2em;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

#generate:hover {
    background-color: var(--button-hover);
    transform: translateY(-2px);
}

#generate:active {
    transform: translateY(1px);
}

.whiteboard-section {
    margin-top: 28px;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px;
}

.board-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.board-controls {
    display: flex;
    gap: 8px;
    align-items: center;
}

.board-controls button {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 8px 12px;
    cursor: pointer;
}

#pen-color {
    width: 38px;
    height: 38px;
    border: none;
    padding: 0;
    background: transparent;
}

#whiteboard {
    display: block;
    width: 100%;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: #ffffff;
    touch-action: none;
}

body.dark #whiteboard {
    background: #0b1220;
}

.inquiry-section {
    margin-top: 28px;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px;
}

.inquiry-form {
    margin-top: 12px;
    display: grid;
    gap: 8px;
}

.inquiry-form label {
    color: var(--text);
    font-size: 0.92rem;
}

.inquiry-form input,
.inquiry-form textarea {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 12px;
    font: inherit;
    color: var(--text);
    background: transparent;
}

.inquiry-form textarea {
    resize: vertical;
    min-height: 120px;
}

.inquiry-form button {
    margin-top: 4px;
    border: none;
    border-radius: 10px;
    background: var(--button-bg);
    color: #ffffff;
    font: inherit;
    padding: 12px 14px;
    cursor: pointer;
}

.inquiry-form button:hover {
    background: var(--button-hover);
}

.comments-section {
    margin-top: 28px;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px;
}

#disqus_thread {
    margin-top: 12px;
}

@media (max-width: 640px) {
    .container {
        padding: 20px;
    }

    .top-bar {
        flex-direction: column;
        align-items: stretch;
    }

    .board-header {
        flex-direction: column;
        align-items: stretch;
    }
}