/* ===== RESET & BASE ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --blue-900: #091E42;
    --blue-700: #0747A6;
    --blue-600: #0052CC;
    --blue-500: #0065FF;
    --blue-100: #DEEBFF;
    --blue-50: #E6F0FF;
    --green-600: #006644;
    --green-100: #E3FCEF;
    --red-600: #BF2600;
    --red-100: #FFEBE6;
    --yellow-600: #FF8B00;
    --yellow-100: #FFFAE6;
    --neutral-900: #091E42;
    --neutral-700: #253858;
    --neutral-500: #5E6C84;
    --neutral-400: #7A869A;
    --neutral-300: #A5ADBA;
    --neutral-200: #C1C7D0;
    --neutral-100: #DFE1E6;
    --neutral-50: #EBECF0;
    --neutral-30: #F4F5F7;
    --neutral-10: #FAFBFC;
    --white: #FFFFFF;
    --shadow-sm: 0 1px 2px rgba(9,30,66,0.08);
    --shadow-md: 0 4px 8px -2px rgba(9,30,66,0.1), 0 0 1px rgba(9,30,66,0.12);
    --shadow-lg: 0 8px 16px -4px rgba(9,30,66,0.1), 0 0 1px rgba(9,30,66,0.12);
    --radius: 6px;
    --radius-lg: 10px;
    --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --focus-ring: 0 0 0 2px var(--blue-500);
}

html {
    font-size: 14px;
}

body {
    font-family: var(--font);
    background: var(--neutral-30);
    color: var(--neutral-900);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== FOCUS STYLES ===== */
*:focus-visible {
    outline: 2px solid var(--blue-500);
    outline-offset: 2px;
}

/* ===== HEADER ===== */
.app-header {
    background: linear-gradient(135deg, var(--blue-700), var(--blue-600));
    color: var(--white);
    padding: 0 24px;
    height: 56px;
    display: flex;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.15);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: 1440px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo h1 {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.3px;
}

.header-badge {
    font-size: 0.75rem;
    background: rgba(255,255,255,0.18);
    padding: 4px 12px;
    border-radius: 12px;
    font-weight: 500;
}

/* ===== MAIN TABS ===== */
.main-tabs {
    background: var(--white);
    border-bottom: 2px solid var(--neutral-100);
    padding: 0 24px;
    display: flex;
    gap: 0;
    position: sticky;
    top: 56px;
    z-index: 90;
    box-shadow: var(--shadow-sm);
}

.main-tab {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 20px;
    border: none;
    background: none;
    color: var(--neutral-500);
    font-size: 0.93rem;
    font-weight: 500;
    cursor: pointer;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
    transition: all 0.15s ease;
    font-family: var(--font);
}

.main-tab:hover {
    color: var(--blue-600);
    background: var(--neutral-10);
}

.main-tab.active {
    color: var(--blue-600);
    border-bottom-color: var(--blue-600);
    font-weight: 600;
}

.main-tab svg {
    flex-shrink: 0;
}

/* ===== CONTENT AREA ===== */
.app-content {
    flex: 1;
    padding: 24px;
    max-width: 1440px;
    width: 100%;
    margin: 0 auto;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* ===== CARD ===== */
.card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    border-bottom: 1px solid var(--neutral-50);
    background: var(--neutral-10);
}

.card-header h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--neutral-900);
}

.card-body {
    padding: 20px;
}

/* ===== GENERAL LAYOUT ===== */
.general-layout {
    display: grid;
    grid-template-columns: 340px 1fr;
    gap: 24px;
    align-items: start;
}

/* ===== STANDARD CALCULATOR ===== */
.calculator-card {
    position: sticky;
    top: 120px;
}

.calc-display {
    background: var(--neutral-900);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 16px;
    min-height: 80px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    overflow: hidden;
}

.calc-history {
    color: var(--neutral-400);
    font-size: 0.85rem;
    text-align: right;
    min-height: 20px;
    word-break: break-all;
}

.calc-input {
    color: var(--white);
    font-size: 1.85rem;
    font-weight: 500;
    text-align: right;
    word-break: break-all;
    letter-spacing: 0.3px;
    font-family: 'Segoe UI', 'Consolas', monospace;
}

.calc-keypad {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
}

.calc-btn {
    padding: 14px 8px;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.1s ease;
    font-family: var(--font);
}

.calc-btn:active {
    transform: scale(0.95);
}

.calc-btn:focus-visible {
    outline: 2px solid var(--blue-500);
    outline-offset: 1px;
    z-index: 1;
}

.calc-btn.number {
    background: var(--neutral-30);
    color: var(--neutral-900);
}

.calc-btn.number:hover {
    background: var(--neutral-100);
}

.calc-btn.operator {
    background: var(--blue-100);
    color: var(--blue-700);
    font-weight: 600;
}

.calc-btn.operator:hover {
    background: #b3d4ff;
}

.calc-btn.func {
    background: var(--neutral-50);
    color: var(--neutral-700);
}

.calc-btn.func:hover {
    background: var(--neutral-200);
}

.calc-btn.memory {
    background: var(--white);
    color: var(--neutral-500);
    font-size: 0.8rem;
    padding: 10px 8px;
    border: 1px solid var(--neutral-100);
}

.calc-btn.memory:hover {
    background: var(--neutral-30);
    color: var(--blue-600);
}

.calc-btn.equals {
    background: var(--blue-600);
    color: var(--white);
    font-weight: 600;
    font-size: 1.15rem;
}

.calc-btn.equals:hover {
    background: var(--blue-700);
}

.calc-btn.power-btn {
    background: var(--blue-100);
    color: var(--blue-700);
    font-weight: 600;
}

.calc-btn.power-btn:hover {
    background: #b3d4ff;
}

.memory-indicator {
    text-align: center;
    font-size: 0.75rem;
    color: var(--blue-600);
    margin-top: 8px;
    min-height: 18px;
    font-weight: 500;
}

/* ===== FINANCIAL TOOLS ===== */
.financial-tools {
    display: grid;
    grid-template-columns: 210px 1fr;
    gap: 0;
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    min-height: 520px;
}

.tool-sidebar {
    background: var(--neutral-10);
    border-right: 1px solid var(--neutral-100);
    padding: 8px 0;
    display: flex;
    flex-direction: column;
}

.tool-tab {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 16px;
    border: none;
    background: none;
    color: var(--neutral-500);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    text-align: left;
    transition: all 0.15s ease;
    border-left: 3px solid transparent;
    font-family: var(--font);
}

.tool-tab:hover {
    background: var(--neutral-30);
    color: var(--neutral-900);
}

.tool-tab.active {
    background: var(--blue-50);
    color: var(--blue-600);
    border-left-color: var(--blue-600);
    font-weight: 600;
}

.tool-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 22px;
    border-radius: 4px;
    font-size: 0.65rem;
    font-weight: 700;
    background: var(--neutral-100);
    color: var(--neutral-500);
    flex-shrink: 0;
    letter-spacing: -0.2px;
}

.tool-tab.active .tool-icon {
    background: var(--blue-600);
    color: var(--white);
}

.tool-content {
    padding: 0;
}

.tool-panel {
    display: none;
}

.tool-panel.active {
    display: block;
}

.tool-panel .card {
    box-shadow: none;
    border-radius: 0;
}

.tool-panel .card-header {
    border-radius: 0;
}

.tool-desc {
    font-size: 0.85rem;
    color: var(--neutral-500);
    margin-bottom: 16px;
    line-height: 1.5;
}

/* ===== FORMS ===== */
.form-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 14px;
    margin-bottom: 16px;
}

.form-grid.two-col {
    grid-template-columns: 1fr 1fr;
}

.form-group label {
    display: block;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--neutral-700);
    margin-bottom: 4px;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 8px 10px;
    border: 2px solid var(--neutral-100);
    border-radius: var(--radius);
    font-size: 0.93rem;
    color: var(--neutral-900);
    background: var(--white);
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
    font-family: var(--font);
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--blue-500);
    box-shadow: var(--focus-ring);
}

.form-group input::placeholder {
    color: var(--neutral-300);
}

.optional {
    font-weight: 400;
    color: var(--neutral-400);
    font-size: 0.78rem;
}

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

.input-row input {
    flex: 1;
}

/* ===== HELP TIPS (data-tip, no native title) ===== */
.help-tip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--neutral-200);
    color: var(--white);
    font-size: 0.7rem;
    font-weight: 700;
    cursor: help;
    vertical-align: middle;
    position: relative;
    border: none;
    padding: 0;
    line-height: 1;
}

.help-tip:hover::after,
.help-tip:focus::after {
    content: attr(data-tip);
    position: absolute;
    bottom: calc(100% + 6px);
    left: 50%;
    transform: translateX(-50%);
    background: var(--neutral-900);
    color: var(--white);
    padding: 8px 12px;
    border-radius: var(--radius);
    font-size: 0.78rem;
    font-weight: 400;
    white-space: normal;
    width: 240px;
    z-index: 50;
    box-shadow: var(--shadow-lg);
    line-height: 1.4;
    pointer-events: none;
}

.help-tip:focus-visible {
    outline: 2px solid var(--blue-500);
    outline-offset: 1px;
}

/* ===== BUTTONS ===== */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 20px;
    background: var(--blue-600);
    color: var(--white);
    border: none;
    border-radius: var(--radius);
    font-size: 0.93rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.15s ease;
    font-family: var(--font);
    width: 100%;
}

.btn-primary:hover {
    background: var(--blue-700);
}

.btn-primary:active {
    transform: scale(0.98);
}

.btn-solve {
    padding: 8px 14px;
    background: var(--blue-600);
    color: var(--white);
    border: none;
    border-radius: var(--radius);
    font-size: 0.82rem;
    font-weight: 600;
    cursor: pointer;
    white-space: nowrap;
    transition: background 0.15s ease;
    font-family: var(--font);
}

.btn-solve:hover {
    background: var(--blue-700);
}

.btn-reset {
    padding: 6px 14px;
    background: none;
    color: var(--neutral-500);
    border: 1px solid var(--neutral-200);
    border-radius: var(--radius);
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.15s ease;
    font-family: var(--font);
}

.btn-reset:hover {
    background: var(--neutral-30);
    color: var(--neutral-700);
    border-color: var(--neutral-300);
}

.btn-toggle {
    display: block;
    width: 100%;
    padding: 10px;
    background: var(--neutral-10);
    color: var(--blue-600);
    border: 1px solid var(--neutral-100);
    border-radius: var(--radius);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    margin-top: 16px;
    transition: background 0.15s ease;
    font-family: var(--font);
}

.btn-toggle:hover {
    background: var(--blue-50);
}

/* ===== RADIO TOGGLE ===== */
.tvm-mode, .dm-mode {
    display: flex;
    gap: 16px;
    margin-bottom: 16px;
    padding: 10px 0;
    border-bottom: 1px solid var(--neutral-50);
}

.toggle-label {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--neutral-700);
    cursor: pointer;
    font-weight: 500;
}

.toggle-label input[type="radio"] {
    accent-color: var(--blue-600);
}

/* ===== RESULT BOX ===== */
.result-box {
    margin-top: 20px;
    padding: 20px;
    background: var(--blue-50);
    border-radius: var(--radius);
    border-left: 4px solid var(--blue-600);
}

.result-box h3 {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--blue-700);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.result-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 0;
    border-bottom: 1px solid rgba(0,82,204,0.08);
    font-size: 0.9rem;
}

.result-row:last-child {
    border-bottom: none;
}

.result-label {
    color: var(--neutral-700);
    font-weight: 500;
}

.result-value {
    font-weight: 700;
    color: var(--neutral-900);
    font-family: 'Segoe UI', 'Consolas', monospace;
}

.result-highlight {
    font-size: 1.6rem;
    text-align: center;
    padding: 16px;
    color: var(--blue-700);
    font-weight: 700;
    background: var(--white);
    border-radius: var(--radius);
    margin-bottom: 16px;
    box-shadow: var(--shadow-sm);
    font-family: 'Segoe UI', 'Consolas', monospace;
}

.result-highlight small {
    display: block;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--neutral-500);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.result-error {
    background: var(--red-100);
    border-left-color: var(--red-600);
    color: var(--red-600);
    font-weight: 500;
}

.result-success {
    background: var(--green-100);
    border-left-color: var(--green-600);
}

.result-warning {
    background: var(--yellow-100);
    border-left-color: var(--yellow-600);
}

/* ===== AMORTIZATION TABLE ===== */
.amort-table-wrapper {
    max-height: 400px;
    overflow-y: auto;
    margin-top: 12px;
    border: 1px solid var(--neutral-100);
    border-radius: var(--radius);
}

.amort-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.82rem;
}

.amort-table th {
    position: sticky;
    top: 0;
    background: var(--neutral-50);
    padding: 10px 12px;
    text-align: right;
    font-weight: 600;
    color: var(--neutral-700);
    border-bottom: 2px solid var(--neutral-200);
}

.amort-table th:first-child {
    text-align: center;
}

.amort-table td {
    padding: 8px 12px;
    text-align: right;
    border-bottom: 1px solid var(--neutral-50);
    font-family: 'Segoe UI', 'Consolas', monospace;
}

.amort-table td:first-child {
    text-align: center;
    color: var(--neutral-500);
    font-weight: 500;
}

.amort-table tbody tr:hover {
    background: var(--blue-50);
}

.amort-table .year-row {
    background: var(--neutral-10);
    font-weight: 600;
}

/* ===== LEASE TAB LAYOUT ===== */
.lease-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    align-items: start;
}

.lease-result-box {
    background: var(--green-100);
    border-left-color: var(--green-600);
}

.lease-result-box h3 {
    color: var(--green-600);
}

/* ===== COMPARISON RESULTS ===== */
.compare-section {
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--neutral-100);
}

.section-title {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--neutral-900);
    margin-bottom: 12px;
    padding-bottom: 6px;
}

.compare-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-top: 20px;
}

.compare-card {
    padding: 20px;
    border-radius: var(--radius);
    border: 2px solid var(--neutral-100);
    text-align: center;
}

.compare-card h4 {
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.compare-card.lease-card {
    border-color: var(--blue-600);
    background: var(--blue-50);
}

.compare-card.lease-card h4 {
    color: var(--blue-600);
}

.compare-card.buy-card {
    border-color: var(--green-600);
    background: var(--green-100);
}

.compare-card.buy-card h4 {
    color: var(--green-600);
}

.compare-big-number {
    font-size: 1.5rem;
    font-weight: 700;
    font-family: 'Segoe UI', 'Consolas', monospace;
    margin-bottom: 8px;
}

.compare-detail {
    font-size: 0.82rem;
    color: var(--neutral-500);
    padding: 4px 0;
}

.verdict-box {
    margin-top: 20px;
    padding: 16px 20px;
    border-radius: var(--radius);
    text-align: center;
    font-weight: 600;
    font-size: 1rem;
}

.verdict-lease {
    background: var(--blue-100);
    color: var(--blue-700);
    border: 2px solid var(--blue-600);
}

.verdict-buy {
    background: var(--green-100);
    color: var(--green-600);
    border: 2px solid var(--green-600);
}

.verdict-warning {
    background: var(--yellow-100);
    color: var(--neutral-700);
    border: 2px solid var(--yellow-600);
    font-weight: 500;
    font-size: 0.85rem;
    line-height: 1.5;
}

/* ===== FOOTER ===== */
.app-footer {
    text-align: center;
    padding: 16px;
    font-size: 0.78rem;
    color: var(--neutral-400);
    border-top: 1px solid var(--neutral-100);
    background: var(--white);
    margin-top: auto;
}

/* ===== ENGINEERING MODE ===== */
.btn-sci-toggle {
    padding: 4px 12px;
    border: 1px solid var(--neutral-200);
    border-radius: var(--radius);
    background: none;
    color: var(--neutral-500);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    font-family: var(--font);
    transition: all 0.15s ease;
}

.btn-sci-toggle:hover {
    background: var(--neutral-30);
    color: var(--neutral-700);
}

.btn-sci-toggle.active {
    background: var(--blue-600);
    color: var(--white);
    border-color: var(--blue-600);
}

.sci-panel {
    margin-bottom: 12px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--neutral-100);
}

.sci-deg-toggle {
    display: flex;
    gap: 0;
    margin-bottom: 10px;
    border: 1px solid var(--neutral-200);
    border-radius: var(--radius);
    overflow: hidden;
}

.sci-deg-btn {
    flex: 1;
    padding: 6px 0;
    border: none;
    background: var(--white);
    color: var(--neutral-500);
    font-size: 0.75rem;
    font-weight: 700;
    cursor: pointer;
    font-family: var(--font);
    transition: all 0.15s ease;
    letter-spacing: 0.5px;
}

.sci-deg-btn.active {
    background: var(--blue-600);
    color: var(--white);
}

.sci-deg-btn:hover:not(.active) {
    background: var(--neutral-30);
    color: var(--neutral-700);
}

.sci-keypad {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 4px;
}

.calc-btn.sci {
    background: var(--neutral-10);
    color: var(--blue-700);
    font-size: 0.78rem;
    font-weight: 600;
    padding: 10px 4px;
    border: 1px solid var(--neutral-100);
    line-height: 1.2;
}

.calc-btn.sci:hover {
    background: var(--blue-50);
    border-color: var(--blue-600);
    color: var(--blue-600);
}

.calc-btn.sci:active {
    transform: scale(0.95);
}

.calc-btn.sci sup,
.calc-btn.sci sub {
    font-size: 0.65rem;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 1100px) {
    .general-layout {
        grid-template-columns: 1fr;
    }

    .calculator-card {
        position: static;
        max-width: 380px;
    }

    .financial-tools {
        grid-template-columns: 180px 1fr;
    }
}

@media (max-width: 900px) {
    .lease-layout {
        grid-template-columns: 1fr;
    }

    .form-grid.two-col {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 700px) {
    .financial-tools {
        grid-template-columns: 1fr;
    }

    .tool-sidebar {
        flex-direction: row;
        overflow-x: auto;
        border-right: none;
        border-bottom: 1px solid var(--neutral-100);
        padding: 0;
    }

    .tool-tab {
        white-space: nowrap;
        border-left: none;
        border-bottom: 3px solid transparent;
        padding: 10px 14px;
    }

    .tool-tab.active {
        border-left: none;
        border-bottom-color: var(--blue-600);
    }

    .app-content {
        padding: 12px;
    }

    .main-tabs {
        padding: 0 12px;
    }
}