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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f0f4f8;
    color: #333;
}

/* ─── Header ─── */
header {
    background-color: #2d6a4f;
    color: white;
    padding: 20px 40px;
    display: flex;
    align-items: center;
    gap: 10px;
}

header h1 {
    font-size: 24px;
}

header p {
    font-size: 13px;
    opacity: 0.8;
    margin-top: 3px;
}

/* ─── Main Layout ─── */
.container {
    display: flex;
    gap: 20px;
    padding: 30px 40px;
    max-width: 1200px;
    margin: 0 auto;
}

/* ─── Left Side ─── */
.left {
    flex: 2;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

textarea {
    width: 100%;
    height: 220px;
    padding: 15px;
    border: 2px solid #ccc;
    border-radius: 10px;
    font-size: 15px;
    resize: vertical;
    outline: none;
    font-family: inherit;
    transition: border 0.3s;
}

textarea:focus {
    border-color: #2d6a4f;
}

.char-count {
    font-size: 12px;
    color: #888;
    text-align: right;
}

.char-count.warning {
    color: #e63946;
}

button {
    background-color: #2d6a4f;
    color: white;
    border: none;
    padding: 14px 30px;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    transition: background 0.3s;
}

button:hover {
    background-color: #1b4332;
}

button:disabled {
    background-color: #aaa;
    cursor: not-allowed;
}

/* ─── Results ─── */
.results {
    background: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    display: none;
}

.results h3 {
    margin-bottom: 15px;
    color: #2d6a4f;
    font-size: 16px;
}

.corrected-text {
    background: #f0fdf4;
    border-left: 4px solid #2d6a4f;
    padding: 12px 15px;
    border-radius: 5px;
    font-size: 15px;
    line-height: 1.6;
    margin-bottom: 20px;
}

.mistake-item {
    background: #fff8f0;
    border-left: 4px solid #f4a261;
    padding: 12px 15px;
    border-radius: 5px;
    margin-bottom: 10px;
}

.mistake-item .wrong {
    color: #e63946;
    font-weight: bold;
    text-decoration: line-through;
}

.mistake-item .correct {
    color: #2d6a4f;
    font-weight: bold;
}

.mistake-item .explanation {
    color: #555;
    font-size: 13px;
    margin-top: 5px;
}

.no-mistakes {
    color: #2d6a4f;
    font-weight: bold;
    text-align: center;
    padding: 20px;
    font-size: 16px;
}

/* ─── Right Side ─── */
.right {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.score-card {
    background: white;
    border-radius: 10px;
    padding: 25px 20px;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    display: none;
}

.score-card h3 {
    font-size: 14px;
    color: #888;
    margin-bottom: 10px;
}

.score-number {
    font-size: 52px;
    font-weight: bold;
    color: #2d6a4f;
}

.score-label {
    font-size: 13px;
    color: #aaa;
}

.summary-card {
    background: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    display: none;
}

.summary-card h3 {
    font-size: 14px;
    color: #888;
    margin-bottom: 10px;
}

.summary-card p {
    font-size: 14px;
    color: #555;
    line-height: 1.6;
}

.mistake-count {
    background: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    display: none;
    text-align: center;
}

.mistake-count h3 {
    font-size: 14px;
    color: #888;
    margin-bottom: 10px;
}

.mistake-count span {
    font-size: 42px;
    font-weight: bold;
    color: #f4a261;
}

/* ─── Loading ─── */
.loading {
    text-align: center;
    padding: 20px;
    color: #888;
    display: none;
}

/* ─── Error ─── */
.error-box {
    background: #fff0f0;
    border-left: 4px solid #e63946;
    padding: 12px 15px;
    border-radius: 5px;
    color: #e63946;
    display: none;
}


/* ─── Responsive Design ─── */

/* Tablet */
@media (max-width: 768px) {
    .container {
        flex-direction: column;
        padding: 20px;
    }

    .left {
        width: 100%;
    }

    .right {
        width: 100%;
        flex-direction: row;
        flex-wrap: wrap;
    }

    .score-card,
    .mistake-count,
    .summary-card {
        flex: 1;
        min-width: 140px;
    }

    header {
        padding: 15px 20px;
    }

    header h1 {
        font-size: 20px;
    }
}

/* Mobile */
@media (max-width: 480px) {
    header h1 {
        font-size: 18px;
    }

    header p {
        font-size: 12px;
    }

    .container {
        padding: 15px;
        gap: 15px;
    }

    textarea {
        height: 180px;
        font-size: 14px;
    }

    button {
        padding: 12px 20px;
        font-size: 14px;
        width: 100%;
    }

    .right {
        flex-direction: column;
    }

    .score-card,
    .mistake-count,
    .summary-card {
        width: 100%;
    }

    .score-number {
        font-size: 40px;
    }

    .mistake-count span {
        font-size: 34px;
    }

    .mistake-item {
        font-size: 13px;
    }

    .corrected-text {
        font-size: 14px;
    }
}