:root {
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --primary-color: #6b8e23;
    --text-main: #000000; /* 텍스트를 순수 검정색으로 */
    --text-sub: #636e72;
    --accent: #e17055;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Inter', 'Noto Sans KR', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
}

#landing-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    text-align: center;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    padding: 20px;
    box-sizing: border-box;
}

.landing-content { max-width: 600px; }
.welcome-label {
    display: inline-block;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.9rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 20px;
}

.landing-title {
    font-size: 2.2rem;
    line-height: 1.4;
    margin-bottom: 24px;
    word-break: keep-all;
}

.landing-description {
    font-size: 1.1rem;
    color: var(--text-sub);
    margin-bottom: 40px;
}

.start-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 18px 48px;
    border-radius: 50px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 10px 20px rgba(107, 142, 35, 0.2);
    transition: all 0.3s;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 40px 20px;
}

header { text-align: center; margin-bottom: 25px; }
.date-label { font-size: 0.8rem; color: var(--text-sub); }
header h1 { margin: 5px 0; font-weight: 600; color: var(--primary-color); }
.subtitle { color: var(--text-sub); font-weight: 300; font-size: 0.9rem; }

.card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 30px;
    box-shadow: var(--shadow);
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
}

/* 프로그레스 바 스타일 */
.progress-container {
    width: 100%;
    height: 4px;
    background-color: #f1f3f5;
    margin: 10px 0 20px;
    border-radius: 2px;
}

.progress-bar {
    width: 0%;
    height: 100%;
    background-color: var(--primary-color);
    border-radius: 2px;
    transition: width 0.1s linear;
}

.badge {
    background: #6b8e23; /* 배경을 메인 컬러로 */
    color: white;
    padding: 4px 14px;
    border-radius: 50px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.5px;
}

/* 영어 문단 스타일 */
.english-text {
    font-size: 1.35rem;
    margin: 24px 0;
    word-break: keep-all;
    line-height: 1.9;
    color: #000; /* 전체 텍스트 기본 검정색 */
}

.word {
    display: inline-block;
    margin-right: 0.18em;
    padding: 1px 3px;
    border-radius: 4px;
    transition: background-color 0.3s ease;
    color: #000;
    opacity: 1;
}

/* 현재 읽고 있는 단어만 배경색 강조 */
.word.highlight {
    background-color: rgba(107, 142, 35, 0.25);
    font-weight: 600;
}

/* 이미 읽었거나 읽을 단어는 배경 없이 검정 글씨 유지 */
.word.past, .word.future {
    background-color: transparent;
    font-weight: 400;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.controls-row { display: flex; gap: 6px; }

.mini-select, .mini-btn {
    background: #f1f3f5;
    border: 1px solid #dfe6e9;
    padding: 6px 12px;
    border-radius: 8px;
    font-size: 0.8rem;
    cursor: pointer;
}

.mini-btn.primary { background: var(--primary-color); color: white; }

.btn-group {
    display: flex;
    justify-content: space-between;
    margin-top: 20px;
}

.toggle-btn, .next-btn {
    background: none;
    border: 1px solid #dfe6e9;
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.85rem;
    cursor: pointer;
    color: var(--text-sub);
}

.next-btn {
    color: var(--primary-color);
    border-color: var(--primary-color);
    font-weight: 600;
}

.korean-text {
    margin-top: 20px;
    padding: 15px;
    background: #fcfcfc;
    border-radius: 8px;
    color: #444;
    font-size: 0.95rem;
}

.hidden { display: none; }
.grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }

.expression-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.expression-list li {
    margin-bottom: 12px;
    line-height: 1.4;
}

.expression-list strong {
    color: var(--primary-color);
    font-size: 0.95rem;
}

.expression-list span {
    font-size: 0.85rem;
    color: var(--text-sub);
}

textarea {
    width: 100%; height: 60px;
    border: 1px solid #dfe6e9;
    border-radius: 8px; padding: 10px;
    font-family: inherit; box-sizing: border-box;
}

.action-area {
    text-align: center; /* 가운데 정렬 */
    margin-top: 40px;
}

.complete-btn {
    background: var(--primary-color); color: white;
    border: none; padding: 16px 60px;
    border-radius: 50px; font-weight: 600; cursor: pointer;
    box-shadow: 0 4px 15px rgba(107, 142, 35, 0.2);
    transition: all 0.3s;
}

.complete-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(107, 142, 35, 0.3);
}

/* (기존 코드 생략) */
footer { text-align: center; margin-top: 40px; color: #b2bec3; font-size: 0.8rem; }

/* 사운드 제어 버튼 */
.sound-toggle {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background: white;
    border: 1px solid #dfe6e9;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    z-index: 1000;
    transition: all 0.3s ease;
}

.sound-toggle:hover {
    transform: scale(1.1);
}

.sound-toggle.off {
    opacity: 0.6;
}