/* ===== Reset & Base Styles ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', sans-serif;
    background-color: #f8f9fa;
    color: #2c3e50;
    line-height: 1.5;
    letter-spacing: 0.3px;
}

/* ===== Color Palette ===== */
:root {
    --primary: #0d47a1;
    --primary-light: #3d5afe;
    --primary-lighter: #6b8fdb;
    --accent: #7c3aed;
    --accent-light: #a78bfa;
    --secondary: #06b6d4;
    --success: #059669;
    --text-dark: #1f2937;
    --text-muted: #6b7280;
    --bg-white: #ffffff;
    --bg-light: #f8f9fa;
    --bg-lighter: #f3f4f6;
    --border: #e5e7eb;
    --border-light: #f0f1f3;
}

/* ===== Layout ===== */
.app-wrapper {
    display: flex;
    min-height: 100vh;
    background-color: var(--bg-light);
}

/* ===== Sidebar ===== */

.sidebar-header {
    padding: 32px 24px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.sidebar-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--bg-white);
    font-weight: 600;
    line-height: 1.3;
    cursor: pointer;
    transition: opacity 0.2s ease;
}

.sidebar-logo:hover {
    opacity: 0.8;
}

.logo-icon {
    font-size: 28px;
    opacity: 0.95;
}

.logo-text {
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 1px;
    opacity: 0.9;
}

.sidebar-nav {
    flex: 1;
    padding: 24px 12px;
    overflow-y: auto;
}

.nav-section {
    margin-bottom: 16px;
}

.nav-section-title {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 1.2px;
    padding: 12px 12px 8px;
    color: rgba(255, 255, 255, 0.6);
    font-weight: 600;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 12px;
    border-radius: 8px;
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: all 0.2s ease;
    font-size: 14px;
    cursor: pointer;
}

.nav-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--bg-white);
}

.nav-link.active {
    background-color: rgba(255, 255, 255, 0.2);
    color: var(--bg-white);
}

.nav-icon {
    font-size: 16px;
    opacity: 0.9;
}

.nav-text {
    flex: 1;
}

.nav-divider {
    height: 1px;
    background-color: rgba(255, 255, 255, 0.1);
    margin: 12px 0;
}

.sidebar-footer {
    padding: 20px 12px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    font-size: 12px;
    color: rgba(255, 255, 255, 0.6);
}

.footer-version,
.footer-year {
    margin: 4px 0;
}

/* ===== Main Container ===== */
.app-container {
    flex: 1;
    margin-left: 260px;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: margin-left 0.3s ease;
}

.app-container.sidebar-collapsed {
    margin-left: 0;
}

/* ===== Sidebar States ===== */
.app-sidebar {
    width: 260px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: var(--bg-white);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    box-shadow: 2px 0 12px rgba(0, 0, 0, 0.08);
    z-index: 1000;
    transition: transform 0.3s ease, width 0.3s ease;
}

.app-sidebar.collapsed {
    transform: translateX(-100%);
}

/* ===== Floating Toggle Button ===== */
.sidebar-toggle-floating {
    position: fixed;
    left: 0;
    top: 20px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    border-radius: 0 12px 12px 0;
    display: none;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 999;
    box-shadow: 2px 2px 8px rgba(0, 0, 0, 0.15);
    transition: all 0.3s ease;
}

.sidebar-toggle-floating.show {
    display: flex;
}

.sidebar-toggle-floating:hover {
    box-shadow: 2px 4px 12px rgba(0, 0, 0, 0.25);
    left: 2px;
}

.toggle-icon {
    font-size: 28px;
    color: var(--bg-white);
    opacity: 0.9;
}

.app-header {
    background: linear-gradient(135deg, var(--bg-white) 0%, var(--bg-lighter) 100%);
    padding: 40px 24px 32px;
    border-bottom: 1px solid var(--border-light);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.header-title-group {
    margin-bottom: 8px;
}

.app-header h1 {
   font-family: "Montserrat", sans-serif;
  font-optical-sizing: auto;
  font-size: 20px;
  font-style: normal; 
}

.brand-subtitle {
    display: none;
}

.tagline {
    font-size: 14px;
    color: var(--text-muted);
    font-weight: 400;
    letter-spacing: 0.2px;
}

.app-main {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    padding: 40px 24px;
}

.app-footer {
    border-top: 1px solid var(--border-light);
    background-color: var(--bg-white);
    padding: 24px;
    text-align: center;
    font-size: 12px;
    color: var(--text-muted);
    margin-left: 260px;
}

.app-footer p {
    margin: 0;
}

/* ===== Calculator Layout (Two Column) ===== */
.calculator-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    margin-bottom: 48px;
}

/* ===== Panel Styling ===== */
.panel {
    background-color: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 32px;
    display: flex;
    flex-direction: column;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
    transition: all 0.2s ease;
}

.panel:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.panel-title {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 24px;
    letter-spacing: 0.2px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--border);
}

/* ===== Input Panel ===== */
.input-grid {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

label {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 6px;
}

.label-text {
    flex: 1;
}

.label-symbol {
    font-size: 12px;
    color: var(--accent);
    font-family: 'Monaco', 'Courier New', monospace;
    font-weight: 600;
}

input[type="number"] {
    padding: 10px 14px;
    font-size: 14px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    background-color: var(--bg-lighter);
    color: var(--text-dark);
    transition: all 0.2s ease;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

input[type="number"]:hover {
    border-color: var(--primary-lighter);
    background-color: var(--bg-white);
}

input[type="number"]:focus {
    outline: none;
    border-color: var(--primary);
    background-color: var(--bg-white);
    box-shadow: 0 0 0 3px rgba(13, 71, 161, 0.1);
}

input[type="number"]::placeholder {
    color: #cbd5e1;
}

/* ===== Output Panel ===== */
.output-panel {
    display: flex;
    flex-direction: column;
}

.results-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.result-card {
    background: linear-gradient(135deg, var(--bg-lighter) 0%, var(--bg-white) 100%);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 24px;
    transition: all 0.2s ease;
}

.result-card:hover {
    border-color: var(--secondary);
    box-shadow: 0 4px 12px rgba(6, 182, 212, 0.08);
}

.result-label {
    font-size: 11px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1.2px;
    margin-bottom: 8px;
    font-weight: 700;
}

.result-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: -0.5px;
    font-family: 'Monaco', 'Courier New', monospace;
}

/* ===== Info Sections (Collapsible) ===== */
.info-section {
    background-color: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: 12px;
    margin-bottom: 16px;
    overflow: hidden;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.section-toggle {
    width: 100%;
    padding: 20px 24px;
    background: none;
    border: none;
    font-size: 14px;
    font-weight: 700;
    color: var(--text-dark);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: all 0.2s ease;
}

.section-toggle:hover {
    background-color: var(--bg-lighter);
}

.section-toggle .toggle-label {
    flex: 1;
    text-align: left;
}

.section-toggle .toggle-icon {
    color: var(--text-muted);
    transition: transform 0.2s ease;
    font-size: 12px;
}

.section-toggle:not(.expanded) .toggle-icon {
    transform: rotate(0deg);
}

.section-toggle.expanded .toggle-icon {
    transform: rotate(90deg);
}

.section-content {
    padding: 0 24px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.section-content.collapsed {
    max-height: 0;
    padding: 0 24px;
}

.section-content:not(.collapsed) {
    max-height: 2000px;
    padding: 0 24px 24px;
}

/* ===== Formula Styling ===== */
.formula-group {
    margin-bottom: 20px;
}

.formula-group h3 {
    font-size: 13px;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.formula-box {
    background: linear-gradient(135deg, var(--bg-lighter) 0%, var(--bg-light) 100%);
    border: 1px solid var(--border);
    border-left: 3px solid var(--primary);
    border-radius: 8px;
    padding: 16px;
    font-size: 13px;
    font-family: 'Monaco', 'Courier New', monospace;
    color: var(--text-dark);
    line-height: 1.8;
    overflow-x: auto;
}

/* ===== Assumptions List ===== */
.assumptions-list {
    list-style: none;
    margin-top: 8px;
}

.assumptions-list li {
    padding: 8px 0;
    color: var(--text-muted);
    font-size: 14px;
    line-height: 1.6;
    position: relative;
    padding-left: 20px;
}

.assumptions-list li:before {
    content: '–';
    position: absolute;
    left: 0;
    color: var(--border);
}

/* ===== Disclaimer ===== */
.disclaimer {
    background: linear-gradient(135deg, rgba(124, 58, 237, 0.05) 0%, rgba(6, 182, 212, 0.05) 100%);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent);
    border-radius: 8px;
    padding: 20px 24px;
    margin-bottom: 0;
}

.disclaimer strong {
    display: block;
    font-size: 13px;
    color: var(--text-dark);
    margin-bottom: 8px;
}

.disclaimer p {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.6;
    margin: 0;
}

/* ===== Modal Styles ===== */
.modal {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--bg-white);
    border-radius: 16px;
    max-width: 600px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    z-index: 2001;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.modal.show {
    display: block;
}

.modal-content {
    padding: 40px;
    position: relative;
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    background: none;
    border: none;
    font-size: 32px;
    color: var(--text-muted);
    cursor: pointer;
    transition: color 0.2s ease;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-close:hover {
    color: var(--text-dark);
}

.modal-content h2 {
    font-size: 24px;
    color: var(--primary);
    margin-bottom: 24px;
    font-weight: 700;
}

.modal-content h3 {
    font-size: 15px;
    color: var(--text-dark);
    margin-top: 20px;
    margin-bottom: 10px;
    font-weight: 600;
}

.modal-content p {
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 16px;
}

.modal-content ul {
    list-style: none;
    padding: 0;
    color: var(--text-muted);
    line-height: 1.8;
}

.modal-content li {
    padding: 8px 0;
    padding-left: 24px;
    position: relative;
}

.modal-content li:before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success);
    font-weight: bold;
}

.modal-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.3);
    z-index: 2000;
}

.modal-overlay.show {
    display: block;
}

/* ===== Feedback Form ===== */
.feedback-form {
    margin: 24px 0;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-dark);
}

.form-group select,
.form-group input,
.form-group textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    color: var(--text-dark);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    transition: all 0.2s ease;
}

.form-group select:focus,
.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(13, 71, 161, 0.1);
}

.submit-button {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: var(--bg-white);
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    width: 100%;
}

.submit-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(13, 71, 161, 0.2);
}

.feedback-note {
    color: var(--text-muted);
    font-size: 12px;
    margin-top: 16px;
    text-align: center;
}

/* ===== Contact Info ===== */
.contact-info {
    margin: 28px 0;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-item {
    padding: 16px;
    background: var(--bg-lighter);
    border-radius: 8px;
    border-left: 4px solid var(--primary);
}

.contact-item h3 {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-dark);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.contact-link {
    font-size: 16px;
    font-weight: 600;
    color: var(--primary);
    text-decoration: none;
    transition: all 0.2s ease;
    display: inline-block;
}

.contact-link:hover {
    color: var(--accent);
    text-decoration: underline;
}

.contact-note {
    color: var(--text-muted);
    font-size: 12px;
    margin-top: 20px;
    text-align: center;
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .app-sidebar {
        width: 240px;
    }

    .app-container,
    .app-footer {
        margin-left: 240px;
    }

    .calculator-layout {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .app-main {
        padding: 32px 20px;
    }
}

@media (max-width: 900px) {
    .app-sidebar {
        width: 220px;
    }

    .app-container,
    .app-footer {
        margin-left: 220px;
    }

    .panel {
        padding: 24px;
    }
}

@media (max-width: 768px) {
    .app-sidebar {
        width: 200px;
    }

    .app-container,
    .app-footer {
        margin-left: 200px;
    }

    .app-header {
        padding: 32px 20px 24px;
    }

    .app-header h1 {
        font-size: 24px;
    }

    .brand-subtitle {
        font-size: 11px;
    }

    .tagline {
        font-size: 13px;
    }

    .panel {
        padding: 20px;
    }

    .panel-title {
        font-size: 15px;
        margin-bottom: 16px;
    }

    .result-value {
        font-size: 24px;
    }

    .modal {
        width: 95%;
        max-height: 90vh;
    }

    .modal-content {
        padding: 32px 24px;
    }
}

@media (max-width: 600px) {
    .app-sidebar {
        width: 180px;
        padding: 0;
    }

    .sidebar-header {
        padding: 24px 16px;
    }

    .sidebar-nav {
        padding: 16px 8px;
    }

    .nav-section-title {
        font-size: 10px;
        padding: 10px 8px 6px;
    }

    .nav-link {
        padding: 10px 8px;
        font-size: 12px;
    }

    .sidebar-footer {
        padding: 16px 8px;
        font-size: 11px;
    }

    .app-container,
    .app-footer {
        margin-left: 180px;
    }

    .app-header h1 {
        font-size: 20px;
    }

    .app-header {
        padding: 24px 16px 20px;
    }

    .app-main {
        padding: 20px 16px;
    }

    .app-footer {
        padding: 16px;
    }

    .calculator-layout {
        grid-template-columns: 1fr;
        gap: 16px;
        margin-bottom: 32px;
    }

    .panel {
        padding: 16px;
    }

    .section-toggle {
        padding: 16px 16px;
    }

    .formula-box {
        font-size: 12px;
        padding: 12px;
    }

    .result-value {
        font-size: 20px;
    }

    .modal {
        max-height: 95vh;
    }

    .modal-content {
        padding: 28px 20px;
    }

    .modal-content h2 {
        font-size: 20px;
    }
}