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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
}

h1 {
    text-align: center;
    color: white;
    margin-bottom: 10px;
    font-size: 2.2em;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.subtitle {
    text-align: center;
    color: rgba(255,255,255,0.9);
    margin-bottom: 30px;
    font-size: 1.1em;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.2);
}

/* Сетка с уменьшенными карточками */
.sections-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

/* Карточки уменьшены в 2 раза */
.section-card {
    background: white;
    border-radius: 15px;
    padding: 20px 15px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.section-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

/* Увеличенные эмодзи */
.section-emoji {
    font-size: 3em;
    margin-bottom: 12px;
}

/* Увеличенный заголовок */
.section-title {
    font-size: 1.4em;
    font-weight: bold;
    color: #333;
    margin-bottom: 8px;
}

/* Увеличенное описание */
.section-desc {
    color: #666;
    font-size: 0.95em;
}

/* Сетка для калькуляторов */
.calc-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 15px;
    margin-top: 30px;
}

/* Карточки калькуляторов */
.calc-card {
    background: white;
    border-radius: 12px;
    padding: 20px 15px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    text-decoration: none;
    color: #333;
    display: block;
}

.calc-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.15);
}

/* Увеличенные иконки */
.calc-icon {
    font-size: 2.5em;
    margin-bottom: 10px;
}

/* Увеличенный заголовок */
.calc-title {
    font-size: 1.1em;
    font-weight: bold;
    margin-bottom: 6px;
}

/* Увеличенное описание */
.calc-desc {
    color: #666;
    font-size: 0.9em;
}

.back-btn {
    position: fixed;
    top: 20px;
    left: 20px;
    background: white;
    border: none;
    padding: 10px 20px;
    border-radius: 25px;
    cursor: pointer;
    font-weight: bold;
    color: #667eea;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    transition: all 0.3s ease;
    z-index: 100;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    font-size: 1em;
}

.back-btn:hover {
    transform: translateX(-5px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}

.placeholder {
    background: white;
    border-radius: 20px;
    padding: 40px 30px;
    text-align: center;
    margin-top: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.placeholder-icon {
    font-size: 4.5em;
    margin-bottom: 18px;
}

.placeholder h2 {
    color: #333;
    margin-bottom: 12px;
    font-size: 1.6em;
}

.placeholder p {
    color: #666;
    font-size: 1.1em;
}

/* ============================================
   АДАПТИВНОСТЬ ДЛЯ МОБИЛЬНЫХ (2 В РЯД)
   ============================================ */

@media (max-width: 768px) {
    body {
        padding: 15px;
    }
    
    h1 {
        font-size: 2em;
        margin-bottom: 8px;
    }
    
    .subtitle {
        font-size: 1em;
        margin-bottom: 25px;
    }
    
    /* На планшетах и мобильных - по 2 в ряд */
    .sections-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px;
    }
    
    .calc-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
    
    /* Карточки на мобильных */
    .section-card {
        padding: 15px 12px;
        border-radius: 12px;
    }
    
    .section-emoji {
        font-size: 2.5em;
        margin-bottom: 8px;
    }
    
    .section-title {
        font-size: 1.2em;
    }
    
    .section-desc {
        font-size: 0.85em;
    }
    
    .calc-card {
        padding: 15px 12px;
        border-radius: 10px;
    }
    
    .calc-icon {
        font-size: 2.2em;
        margin-bottom: 8px;
    }
    
    .calc-title {
        font-size: 1em;
    }
    
    .calc-desc {
        font-size: 0.85em;
    }
    
    .back-btn {
        top: 10px;
        left: 10px;
        padding: 8px 15px;
        font-size: 0.9em;
    }
    
    .placeholder {
        padding: 30px 20px;
        margin-top: 30px;
    }
    
    .placeholder-icon {
        font-size: 3.5em;
    }
    
    .placeholder h2 {
        font-size: 1.4em;
    }
    
    .placeholder p {
        font-size: 1em;
    }
}

/* Для очень маленьких экранов (менее 480px) */
@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    
    h1 {
        font-size: 1.6em;
    }
    
    .subtitle {
        font-size: 0.9em;
        margin-bottom: 20px;
    }
    
    .sections-grid {
        gap: 12px;
    }
    
    .calc-grid {
        gap: 10px;
    }
    
    .section-card {
        padding: 12px 10px;
    }
    
    .section-emoji {
        font-size: 2.2em;
        margin-bottom: 6px;
    }
    
    .section-title {
        font-size: 1.1em;
    }
    
    .section-desc {
        font-size: 0.8em;
    }
    
    .calc-card {
        padding: 12px 10px;
    }
    
    .calc-icon {
        font-size: 2em;
        margin-bottom: 6px;
    }
    
    .calc-title {
        font-size: 0.95em;
    }
    
    .calc-desc {
        font-size: 0.8em;
    }
    
    .back-btn {
        top: 8px;
        left: 8px;
        padding: 6px 12px;
        font-size: 0.85em;
    }
    
    .placeholder {
        padding: 25px 15px;
    }
    
    .placeholder-icon {
        font-size: 3em;
    }
    
    .placeholder h2 {
        font-size: 1.3em;
    }
    
    .placeholder p {
        font-size: 0.95em;
    }
}

/* Для экранов 320px и меньше */
@media (max-width: 320px) {
    .sections-grid {
        gap: 10px;
    }
    
    .calc-grid {
        gap: 8px;
    }
    
    .section-card {
        padding: 10px 8px;
    }
    
    .section-emoji {
        font-size: 2em;
    }
    
    .section-title {
        font-size: 1em;
    }
    
    .section-desc {
        font-size: 0.75em;
    }
    
    .calc-card {
        padding: 10px 8px;
    }
    
    .calc-icon {
        font-size: 1.8em;
    }
    
    .calc-title {
        font-size: 0.9em;
    }
    
    .calc-desc {
        font-size: 0.75em;
    }
}