/* style.css */

.virtual-keyboard {
    display: grid;
    grid-template-columns: repeat(11, 1fr);
    gap: 4px;
    margin: 20px auto 24px auto;
    width: fit-content;
    max-width: 100%;
    justify-content: center;
}

.vk-btn {
    background: #f3f4f6;
    border: 1px solid #d1d5db;
    border-radius: 8px;
    padding: 8px 4px;
    font-size: 1.1rem;
    font-weight: 600;
    color: #374151;
    cursor: pointer;
    transition: all 0.2s;
    user-select: none;
    font-family: 'Inter', sans-serif;
    min-width: 32px;
}

.vk-btn:hover {
    background: #e5e7eb;
}

.vk-btn:active {
    background: #d1d5db;
    transform: scale(0.95);
}

.vk-var {
    color: #4f46e5;
    font-style: italic;
    font-family: 'Times New Roman', Times, serif;
}

.vk-del {
    background: #fee2e2;
    color: #ef4444;
    border-color: #fca5a5;
}

.vk-del:hover {
    background: #fecaca;
}

.vk-del:active {
    background: #fca5a5;
}

.exercise-section {
    text-align: center;
    width: fit-content;
    max-width: 100%;
    margin: 0 auto 16px auto;
    padding: 0px 16px;
    background: #f8fafc;
    border-radius: 12px;
    border: 1px solid #e2e8f0;
}

.math-display {
    font-size: 1.25rem;
    margin: 0;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 0;
}

.math-display .katex-display {
    margin: 4px 0 !important;
}

.input-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    width: 100%;
}

input[type="text"] {
    width: 100%;
    max-width: 400px;
    padding: 12px;
    font-size: 1.25rem;
    text-align: center;
    border: 2px solid #cbd5e1;
    border-radius: 12px;
    transition: all 0.3s;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.05);
    font-family: 'Times New Roman', Times, serif;
}

input[type="text"]:focus {
    outline: none;
    border-color: #4f46e5;
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.2);
}

.btn {
    padding: 8px 16px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.primary-btn {
    background: #4f46e5;
    color: white;
    box-shadow: 0 4px 6px rgba(79, 70, 229, 0.2);
}

.primary-btn:hover {
    background: #4338ca;
    transform: translateY(-1px);
    box-shadow: 0 6px 8px rgba(79, 70, 229, 0.3);
}

.primary-btn:active {
    transform: translateY(1px);
    box-shadow: 0 2px 4px rgba(79, 70, 229, 0.2);
}

.secondary-btn {
    background: #f1f5f9;
    color: #475569;
    border: 1px solid #cbd5e1;
}

.secondary-btn:hover {
    background: #e2e8f0;
}

.app-container {
    width: 100%;
    padding-bottom: 12px;
}

.app-header {
    text-align: center;
    margin-bottom: 16px;
}

.blue-btn {
    background: #3b82f6;
    color: white;
}

.blue-btn:hover {
    background: #2563eb;
}

.feedback {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 16px;
    border-radius: 12px;
    margin-top: 20px;
    width: 100%;
    max-width: 400px;
    font-weight: 600;
    animation: slideUp 0.3s ease-out;
}

.feedback.success {
    background: #dcfce7;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.feedback.error {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}