/* --- Basic Setup & Variables --- */
:root {
    --primary-blue: #007bff;
    --light-blue: #e7f5ff;
    --success-green: #28a745;
    --warning-red: #dc3545;
    --text-color: #333;
    --label-color: #555;
    --border-color: #ccc;
    --background-gradient: linear-gradient(135deg, #46aef6, #1b6ff0);
    --white: #ffffff;
    --light-gray: #f8f9fa;
}

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

body {
    font-family: 'Inter', sans-serif; display: flex; flex-direction: column;
    justify-content: center; align-items: center; min-height: 100vh;
    background: var(--background-gradient); padding: 20px; color: var(--text-color);
}

/* --- Animation Classes --- */
.hidden { display: none !important; }
.fade-in { animation: fadeInAnimation 0.6s ease-out forwards; }
@keyframes fadeInAnimation { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* --- Header & Footer Styles --- */
.page-header { padding: 20px; width: 100%; max-width: 700px; margin-bottom: 20px; }
.header-logos { display: flex; justify-content: center; align-items: center; gap: 40px; background: rgba(255, 255, 255, 0.2); padding: 15px; border-radius: 16px; }
.logo { max-height: 50px; filter: drop-shadow(0 2px 4px rgba(0,0,0,0.1)); }
main { width: 100%; display: flex; justify-content: center; }
.page-footer { width: 100%; max-width: 700px; margin-top: 30px; padding: 20px; text-align: center; color: rgba(255, 255, 255, 0.9); }
.page-footer p { margin-bottom: 10px; font-size: 14px; }
.page-footer a { color: var(--white); font-weight: bold; text-decoration: underline; }
.page-footer a:hover { text-decoration: none; }
.disclaimer { margin-top: 20px; padding: 15px; background: rgba(0, 0, 0, 0.1); border-radius: 8px; font-size: 12px; line-height: 1.6; }
.disclaimer p { margin: 0; }
.copyright { margin-top: 20px; font-size: 12px; color: rgba(255, 255, 255, 0.7); }

/* --- General Calculator Styles --- */
.calculator-container { background-color: var(--white); padding: 30px 40px 40px 40px; border-radius: 24px; box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1); width: 100%; max-width: 700px; }
.tab-nav { display: flex; border-bottom: 2px solid #e0e0e0; margin-bottom: 30px; }
.tab-btn { padding: 12px 20px; cursor: pointer; border: none; background: none; font-size: 16px; font-weight: 600; color: var(--label-color); position: relative; bottom: -2px; border-bottom: 2px solid transparent; transition: color 0.3s, border-color 0.3s; }
.tab-btn.active { color: var(--primary-blue); border-bottom-color: var(--primary-blue); }
.tab-content { display: none; }
.tab-content.active { display: block; }
.calculator-header { text-align: center; margin-bottom: 30px; }
.calculator-header h1 { font-size: 28px; font-weight: 700; }
.calculator-header p { font-size: 16px; color: var(--label-color); margin-top: 8px; }
.mode-toggle { display: flex; border: 1px solid var(--border-color); border-radius: 8px; overflow: hidden; width: 100%; }
.toggle-btn { flex: 1; padding: 12px; border: none; background-color: var(--white); cursor: pointer; font-size: 14px; font-weight: 500; transition: background-color 0.3s, color 0.3s; }
.toggle-btn.active { background-color: var(--primary-blue); color: var(--white); }
.form-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 20px; margin-bottom: 20px; }
.form-group { display: flex; flex-direction: column; width: 100%; }
.form-group.full-width { grid-column: 1 / -1; }
.form-group label { font-size: 14px; color: var(--label-color); margin-bottom: 8px; }
.form-group input { padding: 12px; border: 1px solid var(--border-color); border-radius: 8px; font-size: 16px; width: 100%; }
.form-group input:focus { outline: none; border-color: var(--primary-blue); box-shadow: 0 0 0 3px var(--light-blue); }
.action-buttons { display: flex; gap: 15px; margin-top: 20px; }
.btn { flex: 1; padding: 14px; border-radius: 8px; border: none; font-size: 16px; font-weight: 700; cursor: pointer; transition: background-color 0.3s, opacity 0.3s, border-color 0.3s; }
.btn-primary { background-color: var(--primary-blue); color: var(--white); }
.btn-primary:hover { opacity: 0.9; }
.btn-secondary { background-color: transparent; color: var(--primary-blue); border: 1px solid var(--primary-blue); }
.btn-secondary:hover { background-color: var(--light-blue); }

/* --- Tab 1 Specific --- */
.version-toggle-wrapper { text-align: center; margin: 15px 0 25px 0; }
.version-toggle-btn { background-color: var(--light-gray); border: 1px solid var(--border-color); color: var(--label-color); font-size: 14px; cursor: pointer; padding: 8px 15px; border-radius: 8px; transition: background-color 0.3s, color 0.3s; }
.version-toggle-btn:hover { background-color: #e2e6ea; color: var(--text-color); }
.price-selection-group { margin-top: 20px; display: flex; flex-direction: column; gap: 15px; }
.price-option-group { display: flex; align-items: center; gap: 15px; padding: 10px; border-radius: 8px; border: 1px solid #eee; transition: border-color 0.3s, background-color 0.3s; }
.price-option-group:has(input:checked) { border-color: var(--primary-blue); background-color: var(--light-blue); }
.price-option-group input[type="radio"] { flex-shrink: 0; transform: scale(1.2); }
.price-reference { border-left: 3px solid #eee; padding-left: 20px; margin-left: 20px; }

/* --- Results Sections --- */
.results-section { background-color: var(--light-gray); border-radius: 16px; padding: 25px; margin-top: 30px; }
.results-section h2, .section-title { font-size: 20px; margin-bottom: 20px; text-align: center; }
.result-item { background-color: var(--white); padding: 20px; border-radius: 12px; text-align: center; border: 1px solid #e0e0e0; }
.result-item .label { font-size: 14px; color: var(--label-color); }
.result-item .value { font-size: 28px; font-weight: 700; margin-top: 8px; word-wrap: break-word; transition: color 0.3s, font-size 0.3s; }
.result-item .unit { font-size: 16px; font-weight: 400; color: var(--label-color); }
.result-item.result-item-primary .value { font-size: 2.5em; color: var(--success-green); }
.result-item .value.savings { color: var(--success-green); }
.result-item .value.cost-increase { color: var(--warning-red); }
.value-subtext, .result-subtext { display: block; font-size: 13px; font-weight: 400; font-style: italic; color: var(--label-color); margin-top: 8px; }
.results-grid.four-items { display: flex; flex-wrap: wrap; gap: 20px; }
.results-grid.four-items > .result-item { flex-basis: calc(50% - 10px); }
.dynamic-note { font-style: italic; font-size: 14px; color: var(--label-color); margin-top: 20px; padding: 15px; background-color: var(--white); border-radius: 8px; line-height: 1.6; }
.dynamic-note ul { list-style-position: inside; padding-left: 0; margin-top: 5px; }
.dynamic-note strong { color: var(--text-color); }

/* --- Tab 2 Specific --- */
.visual-section { background-color: var(--light-gray); border-radius: 16px; padding: 25px; margin-top: 30px; }
#fuel-gauge-visual { display: flex; flex-wrap: nowrap; overflow-x: auto; gap: 10px; padding: 10px 10px 15px 10px; border-radius: 12px; min-height: 80px; -webkit-overflow-scrolling: touch; scrollbar-width: thin; }
#fuel-gauge-visual::-webkit-scrollbar { height: 8px; }
#fuel-gauge-visual::-webkit-scrollbar-thumb { background: #ccc; border-radius: 4px; }
.bar-wrapper { flex: 1 0 85px; min-width: 85px; text-align: center; animation: popIn 0.4s ease-out backwards; }
@keyframes popIn { from { opacity: 0; transform: scale(0.95) translateY(10px); } to { opacity: 1; transform: scale(1) translateY(0); } }
.bar-label { font-size: 12px; font-weight: 500; color: var(--label-color); margin-bottom: 4px; }
.gauge-bar { padding: 10px 5px; border-radius: 6px; font-weight: 600; font-size: 12px; color: var(--text-color); transition: all 0.3s ease; border: 1px solid transparent; }
.gauge-bar span { display: block; line-height: 1.4; }
.gauge-bar.current { background-color: var(--primary-blue); color: var(--white); border-color: #0056b3; }
.gauge-bar.needed { background-color: #e9ecef; border: 1px dashed var(--border-color); color: var(--label-color); }
.scroll-instruction { text-align: center; font-size: 12px; color: var(--label-color); margin-top: 15px; }
.results-grid-topup { display: flex; flex-wrap: wrap; gap: 20px; }
.results-grid-topup > .result-item { flex-basis: calc(50% - 10px); }
.result-item.full-width { flex-basis: 100%; }

/* --- Tab 3 Specific --- */
.price-info { text-align: center; margin-bottom: 25px; padding: 15px; background-color: var(--light-blue); border-radius: 12px; font-size: 14px; }
.results-grid-dvs { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.result-item.dvs-original { background-color: var(--light-blue); }

/* --- Responsive & Other Styles --- */
@media (max-width: 768px) {
    .results-grid-dvs { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
    body { padding: 10px; }
    .calculator-container { padding: 20px; }
    .calculator-header h1 { font-size: 24px; }
    .toggle-btn { font-size: 12px; }
    .results-grid.four-items > .result-item, .results-grid-topup > .result-item { flex-basis: 100%; order: 0 !important; }
    .price-reference { margin-left: 0; padding-left: 15px; }
}

/* --- Styles for source.html --- */
.source-content .calculator-header h1 { margin-bottom: 8px; }
.source-content .subtitle { font-size: 16px; color: var(--label-color); margin-top: 0; margin-bottom: 30px; max-width: 60ch; margin-left: auto; margin-right: auto; }
.reference-list { margin-top: 20px; }
.reference-item { padding: 20px 0; border-bottom: 1px solid #eee; }
.reference-item:first-of-type { padding-top: 0; }
.reference-item:last-of-type { border-bottom: none; padding-bottom: 0; }
.reference-item h3 { margin-bottom: 15px; color: var(--primary-blue); font-size: 1.2em; }
.reference-item p { margin-bottom: 10px; line-height: 1.6; font-size: 16px; }
.reference-item a { color: var(--primary-blue); text-decoration: none; word-break: break-all; }
.reference-item a:hover { text-decoration: underline; }
.reference-note { font-style: italic; font-size: 14px; color: #555; background-color: #f8f9fa; padding: 10px; border-radius: 6px; margin-top: 15px; }