:root {
    --primary-color: #FF9F43; /* Orange */
    --primary-dark: #e67e22;
    --secondary-color: #54a0ff; /* Blue */
    --secondary-dark: #2e86de;
    --accent-color: #ff6b6b; /* Red */
    --bg-cartoon: #fff9e6; /* Warm White */
    --text-primary: #2d3436;
    --text-secondary: #636e72;
    --border-color: #dfe6e9;
    --card-bg: #ffffff;
    --font-header: "Comic Sans MS", "Chalkboard SE", sans-serif;
    --font-body: "Microsoft YaHei", "Heiti SC", sans-serif;
}

body {
    background-color: var(--bg-cartoon);
    background-image: radial-gradient(#ffeaa7 15%, transparent 16%), radial-gradient(#ffeaa7 15%, transparent 16%);
    background-size: 60px 60px;
    background-position: 0 0, 30px 30px;
    font-family: var(--font-body);
    color: var(--text-primary);
}

/* Common Header Style */
.tool-header h1 {
    color: var(--accent-color);
    font-family: var(--font-header);
    text-shadow: 3px 3px 0px #fff;
}

/* Bubbly Buttons */
.btn-bubble {
    border: none;
    border-radius: 15px;
    padding: 10px 25px;
    font-weight: bold;
    cursor: pointer;
    transition: transform 0.1s, box-shadow 0.1s;
    font-family: inherit;
    display: inline-block;
    text-decoration: none;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 5px 0 var(--primary-dark);
}

.btn-primary:active {
    transform: translateY(5px);
    box-shadow: 0 0 0 var(--primary-dark);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
    box-shadow: 0 5px 0 var(--secondary-dark);
}

.btn-secondary:active {
    transform: translateY(5px);
    box-shadow: 0 0 0 var(--secondary-dark);
}

/* Card Style */
.card-bubble {
    background: var(--card-bg);
    border-radius: 25px;
    box-shadow: 0 10px 0 rgba(0,0,0,0.05);
    border: 3px solid transparent;
    transition: all 0.3s;
}

.card-bubble:hover {
    border-color: #ffeaa7;
    transform: translateY(-2px);
}

/* Navigation Back Button */
.nav-back-btn {
    position: fixed;
    top: 20px;
    left: 20px;
    background: white;
    padding: 10px 20px;
    border-radius: 30px;
    text-decoration: none;
    color: #333;
    box-shadow: 0 4px 0 rgba(0,0,0,0.1);
    font-weight: bold;
    z-index: 100;
    border: 2px solid var(--border-color);
    transition: all 0.2s;
}

.nav-back-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 0 rgba(0,0,0,0.1);
    border-color: var(--secondary-color);
    color: var(--secondary-color);
}

@media (max-width: 600px) {
    .nav-back-btn {
        position: absolute;
    }
}