:root {
    --bg-gradient-start: #f8fafc;
    --bg-gradient-end: #e2e8f0;
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.8);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.1);
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --accent-color: #6366f1;
    --accent-hover: #4f46e5;
    --error-color: #ef4444;
}

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

body {
    font-family: 'Inter', sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.top-nav {
    display: flex;
    align-items: center;
    padding: 16px 40px;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.05);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    transition: opacity 0.25s ease;
}

.logo:hover {
    opacity: 0.88;
}

.logo-icon-wrap {
    width: 38px;
    height: 38px;
    border-radius: 11px;
    background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.45);
    flex-shrink: 0;
    transition: box-shadow 0.35s ease, transform 0.35s ease;
}

.logo:hover .logo-icon-wrap {
    box-shadow: 0 6px 22px rgba(99, 102, 241, 0.6);
    transform: rotate(-8deg) scale(1.08);
}

.logo-icon {
    width: 20px;
    height: 20px;
    stroke: white;
}

.logo-text {
    font-size: 18px;
    font-weight: 800;
    letter-spacing: -0.4px;
    line-height: 1;
}

.logo-main {
    color: var(--text-primary);
}

.logo-tld {
    color: var(--accent-color);
}

.app-wrapper {
    flex: 1;
    display: flex;
    padding: 40px 20px;
}

.app-container {
    width: 100%;
    max-width: 550px;
    margin: auto;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-radius: 24px;
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    padding: 40px;
    animation: fadeIn 0.8s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.app-header {
    text-align: center;
    margin-bottom: 30px;
}

.app-header h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(to right, #4f46e5, #9333ea);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.app-header p {
    color: var(--text-secondary);
    font-size: 14px;
}

.input-section {
    margin-bottom: 24px;
}

.input-section h2 {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 12px;
    color: var(--text-secondary);
}

.date-dropdowns {
    display: flex;
    gap: 12px;
}

.dropdown-group {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.dropdown-group label {
    font-size: 12px;
    margin-bottom: 4px;
    color: var(--text-secondary);
}

select {
    width: 100%;
    padding: 12px;
    border-radius: 12px;
    border: 1px solid var(--glass-border);
    background: rgba(0, 0, 0, 0.04);
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    appearance: none;
    outline: none;
    transition: all 0.3s ease;
    cursor: pointer;
}

select:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

select option {
    background-color: var(--bg-gradient-end);
    color: var(--text-primary);
}

.submit-btn {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: 12px;
    background: var(--accent-color);
    color: white;
    font-size: 16px;
    font-weight: 600;
    font-family: 'Inter', sans-serif;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow: hidden;
    margin-top: 10px;
}

.submit-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.submit-btn:active {
    transform: translateY(0);
}

.loader {
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.hidden {
    display: none !important;
}

.result-container {
    margin-top: 30px;
    text-align: center;
    animation: slideUp 0.5s ease-out;
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.result-container h3 {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.result-cards {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.result-card {
    background: rgba(0, 0, 0, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 16px 10px;
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: transform 0.3s ease;
}

.result-card:hover {
    transform: scale(1.05);
}

.result-number {
    font-size: 32px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
    background: linear-gradient(to bottom, #4338ca, #6366f1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.result-label {
    font-size: 12px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.extra-results {
    margin-top: 24px;
    padding-top: 20px;
    border-top: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 14px;
    color: var(--text-secondary);
}

.extra-results p {
    display: flex;
    justify-content: space-between;
    background: rgba(0, 0, 0, 0.04);
    padding: 10px 16px;
    border-radius: 8px;
}

.extra-results span {
    font-weight: 600;
    color: var(--text-primary);
}

.countdown-container {
    margin-top: 24px;
    padding: 12px;
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid var(--accent-color);
    border-radius: 8px;
    text-align: center;
    color: var(--text-primary);
    font-weight: 600;
}

.countdown-container.hidden {
    display: none;
}

.share-btn {
    margin-top: 24px;
    width: 100%;
    padding: 14px;
    background: transparent;
    border: 2px solid var(--accent-color);
    color: var(--accent-color);
    font-size: 16px;
    font-weight: 600;
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.share-btn:hover {
    background: rgba(99, 102, 241, 0.05);
}

.share-icon {
    width: 20px;
    height: 20px;
}

.error-message {
    margin-top: 20px;
    padding: 12px;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: 8px;
    color: var(--error-color);
    font-size: 14px;
    text-align: center;
}

.about-section {
    margin-top: 40px;
    padding: 30px;
    background: var(--glass-bg);
    border-radius: 20px;
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    color: var(--text-secondary);
}

.about-section article {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.about-section h2, .about-section h3 {
    color: var(--text-primary);
    font-weight: 600;
}

.about-section h2 {
    font-size: 18px;
}

.about-section h3 {
    font-size: 16px;
    margin-top: 8px;
}

.about-section p {
    font-size: 14px;
    line-height: 1.6;
}

.about-section strong {
    color: var(--text-primary);
}

.site-footer {
    text-align: center;
    padding: 24px 20px;
    background: var(--glass-bg);
    border-top: 1px solid var(--glass-border);
    color: var(--text-secondary);
    font-size: 14px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    flex-wrap: wrap;
    margin-bottom: 12px;
}

.footer-links a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.footer-links a:hover {
    color: var(--accent-color);
}

.text-page {
    background: var(--glass-bg);
    border-radius: 20px;
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    padding: 40px;
    color: var(--text-secondary);
}

.text-page h1 {
    color: var(--text-primary);
    font-size: 28px;
    margin-bottom: 24px;
    text-align: center;
}

.text-page h2 {
    color: var(--text-primary);
    font-size: 20px;
    margin-top: 32px;
    margin-bottom: 16px;
}

.text-page p, .text-page ul {
    font-size: 15px;
    line-height: 1.6;
    margin-bottom: 16px;
}

.text-page ul {
    padding-left: 20px;
}

.text-page a {
    color: var(--accent-color);
    text-decoration: none;
}

.text-page a:hover {
    text-decoration: underline;
}

/* ==========================================================================
   Tab Navigation & Multi-Theme System
   ========================================================================== */

/* Custom Themes overrides */
body.theme-sunset {
    --bg-gradient-start: #fff7ed;
    --bg-gradient-end: #ffedd5;
    --accent-color: #f97316;
    --accent-hover: #ea580c;
}
body.theme-emerald {
    --bg-gradient-start: #f0fdf4;
    --bg-gradient-end: #dcfce7;
    --accent-color: #10b981;
    --accent-hover: #059669;
}
body.theme-violet {
    --bg-gradient-start: #faf5ff;
    --bg-gradient-end: #f3e8ff;
    --accent-color: #8b5cf6;
    --accent-hover: #7c3aed;
}
body.theme-rose {
    --bg-gradient-start: #fff1f2;
    --bg-gradient-end: #ffe4e6;
    --accent-color: #f43f5e;
    --accent-hover: #e11d48;
}
body.theme-dark {
    --bg-gradient-start: #0f172a;
    --bg-gradient-end: #020617;
    --glass-bg: rgba(15, 23, 42, 0.65);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.4);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #38bdf8;
    --accent-hover: #0ea5e9;
}
body.theme-dark select {
    background: rgba(255, 255, 255, 0.04);
}
body.theme-dark select option {
    background: #1e293b;
    color: #f8fafc;
}
body.theme-dark .logo-icon-wrap {
    background: linear-gradient(135deg, #38bdf8 0%, #6366f1 100%);
    box-shadow: 0 4px 14px rgba(56, 189, 248, 0.4);
}
body.theme-dark .logo:hover .logo-icon-wrap {
    box-shadow: 0 6px 22px rgba(56, 189, 248, 0.55);
}
body.theme-dark .result-card {
    background: rgba(255, 255, 255, 0.02);
}
body.theme-dark .extra-results p {
    background: rgba(255, 255, 255, 0.03);
}
body.theme-dark input {
    background: rgba(255, 255, 255, 0.04);
    color: #f8fafc;
    border-color: rgba(255, 255, 255, 0.1);
}

/* Tab Navigation */
.tab-nav {
    display: flex;
    gap: 8px;
    margin-bottom: 24px;
    padding: 4px;
    background: rgba(0, 0, 0, 0.03);
    border-radius: 12px;
}

body.theme-dark .tab-nav {
    background: rgba(255, 255, 255, 0.03);
}

.tab-btn {
    flex: 1;
    padding: 10px 16px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Inter', sans-serif;
}

.tab-btn:hover {
    color: var(--text-primary);
}

.tab-btn.active {
    background: white;
    color: var(--accent-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

body.theme-dark .tab-btn.active {
    background: #1e293b;
    color: var(--accent-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

/* Form inputs & styling */
.input-group {
    display: flex;
    flex-direction: column;
    margin-bottom: 16px;
}

.input-group label {
    font-size: 12px;
    margin-bottom: 6px;
    color: var(--text-secondary);
    font-weight: 500;
}

.input-group label .required {
    color: var(--error-color);
}

input[type="text"] {
    width: 100%;
    padding: 12px;
    border-radius: 12px;
    border: 1px solid var(--glass-border);
    background: rgba(0, 0, 0, 0.04);
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    outline: none;
    transition: all 0.3s ease;
}

input[type="text"]:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

body.theme-dark input[type="text"]:focus {
    box-shadow: 0 0 0 2px rgba(56, 189, 248, 0.2);
}

/* Theme Grid */
.theme-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-top: 8px;
}

.theme-card {
    position: relative;
    cursor: pointer;
}

.theme-card input[type="radio"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.theme-card-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    padding: 10px;
    border-radius: 12px;
    border: 1px solid var(--glass-border);
    background: rgba(0, 0, 0, 0.02);
    transition: all 0.3s ease;
}

.theme-card:hover .theme-card-content {
    transform: translateY(-2px);
    background: rgba(0, 0, 0, 0.04);
}

.theme-card input[type="radio"]:checked + .theme-card-content {
    border-color: var(--accent-color);
    background: rgba(99, 102, 241, 0.05);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

body.theme-dark .theme-card input[type="radio"]:checked + .theme-card-content {
    background: rgba(56, 189, 248, 0.08);
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(56, 189, 248, 0.2);
}

.theme-preview {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.theme-preview.t-indigo { background: linear-gradient(135deg, #6366f1, #4f46e5); }
.theme-preview.t-sunset { background: linear-gradient(135deg, #f97316, #ea580c); }
.theme-preview.t-emerald { background: linear-gradient(135deg, #10b981, #059669); }
.theme-preview.t-violet { background: linear-gradient(135deg, #8b5cf6, #7c3aed); }
.theme-preview.t-rose { background: linear-gradient(135deg, #f43f5e, #e11d48); }
.theme-preview.t-dark { background: linear-gradient(135deg, #1e293b, #0f172a); }

.theme-label {
    font-size: 11px;
    font-weight: 500;
    color: var(--text-secondary);
}

/* Share Link Box */
.share-link-wrapper {
    margin-top: 20px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

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

.copy-input-group input {
    flex: 1;
    padding: 12px;
    border-radius: 12px;
    border: 1px solid var(--glass-border);
    background: rgba(0, 0, 0, 0.04);
    color: var(--text-primary);
    font-size: 14px;
    outline: none;
    font-family: monospace;
}

.copy-btn {
    padding: 0 16px;
    border: none;
    border-radius: 12px;
    background: var(--accent-color);
    color: white;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.copy-btn:hover {
    background: var(--accent-hover);
}

.btn-secondary {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    padding: 14px;
    border: 2px solid var(--accent-color);
    color: var(--accent-color);
    background: transparent;
    font-size: 16px;
    font-weight: 600;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    text-align: center;
}

.btn-secondary:hover {
    background: rgba(99, 102, 241, 0.05);
}

body.theme-dark .btn-secondary:hover {
    background: rgba(56, 189, 248, 0.08);
}

/* Extra Utility Styles */
.text-center {
    text-align: center;
}

.loader-centered {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px 0;
}

.verification-badge {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.3);
    color: #d97706;
    font-size: 12px;
    font-weight: 600;
    padding: 8px 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    text-align: center;
}

.verification-badge.success {
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.3);
    color: #059669;
}

/* Share Card Panel */
.share-card-panel {
    margin-top: 32px;
    padding: 24px;
    background: rgba(255, 255, 255, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.6);
    border-radius: 20px;
    text-align: left;
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.02);
}

body.theme-dark .share-card-panel {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
}

.share-card-panel h3 {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 6px;
    text-align: left;
}

.share-card-desc {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.5;
    text-align: left;
}

.share-card-form {
    margin-top: 16px;
}