* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 20px;
}

.header {
    text-align: center;
    margin-bottom: 20px;
}

.header h1 {
    font-size: 36px;
    font-weight: 700;
    color: #1a1a1a;
    margin-bottom: 10px;
}

.header p {
    font-size: 17px;
    color: #666;
}

.main-card {
    background: white;
    padding: 24px;
}

.textarea-section label {
    display: block;
    font-size: 15px;
    font-weight: 600;
    color: #333;
    margin-bottom: 10px;
}

#text-input {
    width: 100%;
    height: 500px;
    padding: 12px;
    border: 1px solid #ced4da;
    border-radius: 0.25rem;
    background-color: #f9f9f9;
    font-size: 1rem;
    line-height: 1.5;
    resize: vertical;
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

#text-input:focus {
    color: #495057;
    background-color: #fff;
    border-color: #80bdff;
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(0,123,255,0.25);
}

.stats {
    margin-top: 10px;
    font-size: 14px;
    color: #666;
    text-align: right;
    font-weight: 500;
}

.control-buttons {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-top: 20px;
}

.control-btn {
    padding: 0.375rem .75rem;
    border: 1px solid;
    border-radius: 0.25rem;
    font-size: 1rem;
    font-weight: 400;
    cursor: pointer;
    transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.btn-copy {
    color: #ffffff;
    border-color: #b00923;
    background-color: #b00923;
}

.btn-copy:hover {
    color: #fff;
    background-color: #0069d9;
    border-color: #0062cc;
}

.btn-copy:focus {
    color: #fff;
    background-color: #0069d9;
    border-color: #0062cc;
    box-shadow: 0 0 0 0.2rem rgba(38,143,255,0.5);
}

.btn-download {
    color: #ffffff;
    border-color: #b00923;
    background-color: #b00923;
}

.btn-download:hover {
    color: #fff;
    background-color: #0069d9;
    border-color: #0062cc;
}

.btn-download:focus {
    color: #fff;
    background-color: #0069d9;
    border-color: #0062cc;
    box-shadow: 0 0 0 0.2rem rgba(38,143,255,0.5);
}

.btn-clear {
    color: #fff;
    background-color: #6c757d;
    border-color: #6c757d;
}

.btn-clear:hover {
    color: #fff;
    background-color: #545b62;
    border-color: #4e555b;
}

.btn-clear:focus {
    color: #fff;
    background-color: #5a6268;
    border-color: #545b62;
    box-shadow: 0 0 0 0.2rem rgba(130,138,145,0.5);
}

.filter-section {
    margin-top: 20px;
}

#filter-input {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid #ced4da;
    border-radius: 0.25rem;
    font-size: 14px;
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

#filter-input:focus {
    color: #495057;
    background-color: #fff;
    border-color: #80bdff;
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(0,123,255,0.25);
}

.actions-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid #e0e0e0;
}

.action-btn {
    padding: 0.375rem .75rem;
    color: #ffffff;
    background-color: #b00923;
    border: 1px solid #b00923;
    border-radius: 0.25rem;
    font-size: 1rem;
    font-weight: 400;
    cursor: pointer;
    transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
    text-align: center;
}

.action-btn:hover {
    color: #fff;
    background-color: #0069d9;
    border-color: #0062cc;
}

.action-btn:focus {
    color: #fff;
    background-color: #0069d9;
    border-color: #0062cc;
    box-shadow: 0 0 0 0.2rem rgba(38,143,255,0.5);
}

@media (max-width: 768px) {
    .container {
        max-width: 100%;
        padding: 20px 15px;
    }

    .main-card {
        padding: 20px;
    }

    .actions-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .control-buttons {
        grid-template-columns: 1fr;
    }

    #text-input {
        height: 300px;
    }
}

@media (max-width: 480px) {
    .actions-grid {
        grid-template-columns: 1fr;
    }
}