/*
 * Copyright © 2025 IUSCI. All rights reserved.
 *
 * This software and its source code were initially developed by:
 * - Spyridon Eftychios Kokotos (skokotos@ionio.gr)
 * - Evangelos Konstantinidis (inf2021113@ionio.gr)
 *
 * Redistribution and use in source and binary forms, with or without modification,  
 * are permitted under the terms of the MIT License.  
 * See the LICENSE file distributed with this work for detailed terms and conditions.
 *
 * This software is provided "as is," without warranty of any kind, express or implied,  
 * including but not limited to the warranties of merchantability, fitness for a  
 * particular purpose, and non-infringement.  
 *
 * IUSCI 2026 - Professional IT Conference Theme (External CSS)
 * This file provides fallback / shared styles. Primary styles are inlined in index.php.
*/

:root {
  --primary: #00d4ff;
  --primary-dim: rgba(0, 212, 255, 0.12);
  --secondary: #0066ff;
  --accent: #7c3aed;
  --bg-dark: #0a0e1a;
  --bg-card: rgba(15, 23, 42, 0.88);
  --bg-glass: rgba(255, 255, 255, 0.03);
  --border-subtle: rgba(0, 212, 255, 0.1);
  --border-glow: rgba(0, 212, 255, 0.3);
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-bright: #f8fafc;
  --blur: blur(20px);
  --radius: 14px;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }

html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  font-family: var(--font-main);
  background: var(--bg-dark);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* -- Grid Background -- */
.grid-bg {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(0, 212, 255, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 212, 255, 0.025) 1px, transparent 1px);
  background-size: 64px 64px;
}

.grid-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 15% 50%, rgba(0, 102, 255, 0.07) 0%, transparent 55%),
    radial-gradient(ellipse at 80% 15%, rgba(124, 58, 237, 0.05) 0%, transparent 45%),
    radial-gradient(ellipse at 50% 85%, rgba(0, 212, 255, 0.04) 0%, transparent 50%);
}

/* -- Particles -- */
#particles-js {
  position: fixed;
  inset: 0;
  z-index: 1;
}

/* -- Top Bar -- */
.top-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 14, 26, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
}

.top-bar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

/* -- Content -- */
.content-wrapper {
  position: relative;
  z-index: 2;
  padding: 16px 15px 80px;
  flex: 1;
}

/* -- Quote -- */
.fade-quote { opacity: 0; transition: opacity 0.6s ease-in-out; }
.fade-quote.show { opacity: 1; }

.quote-box {
  background: rgba(0, 212, 255, 0.035);
  padding: 14px 18px;
  border-left: 3px solid var(--primary);
  font-style: italic;
  font-size: 0.85rem;
  color: var(--text-muted);
  border-radius: 0 8px 8px 0;
  line-height: 1.65;
}

/* -- Card -- */
.reg-card {
  border-radius: var(--radius);
  background: var(--bg-card);
  backdrop-filter: var(--blur);
  border: 1px solid var(--border-subtle);
  box-shadow: 0 4px 48px rgba(0, 0, 0, 0.3);
  color: var(--text);
  overflow: hidden;
}

.reg-card .card-header {
  background: linear-gradient(135deg, rgba(0, 102, 255, 0.1), rgba(0, 212, 255, 0.06));
  border-bottom: 1px solid var(--border-subtle);
  border-radius: var(--radius) var(--radius) 0 0 !important;
  padding: 24px 28px;
  text-align: center;
  position: relative;
}

.reg-card .card-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--primary), var(--secondary), var(--accent), transparent);
}

.reg-card .card-header img {
  width: 48px;
  height: 48px;
  margin-bottom: 10px;
  filter: drop-shadow(0 0 10px rgba(0, 212, 255, 0.25));
}

.reg-card .card-header h3 {
  margin: 0;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text-bright);
}

.reg-card .card-body {
  padding: 28px 32px 36px;
}

/* -- Form -- */
.form-group {
  margin-bottom: 16px;
  padding: 12px 14px;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.015);
  border: 1px solid transparent;
  transition: background 0.25s, border-color 0.25s, box-shadow 0.25s;
}

.form-group:hover {
  background: rgba(0, 212, 255, 0.02);
  border-color: rgba(0, 212, 255, 0.06);
}

.form-group:focus-within {
  background: rgba(0, 212, 255, 0.04);
  border-color: var(--border-glow);
  box-shadow: 0 0 16px rgba(0, 212, 255, 0.04);
}

.form-group label {
  font-weight: 500;
  font-size: 0.82rem;
  color: var(--text);
  margin-bottom: 7px;
  display: block;
}

.form-group label i {
  color: var(--primary);
  width: 16px;
  text-align: center;
  margin-right: 6px;
  opacity: 0.8;
}

.form-control {
  background: rgba(15, 23, 42, 0.6) !important;
  color: var(--text-bright) !important;
  border: 1px solid rgba(148, 163, 184, 0.15);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 0.9rem;
  font-family: var(--font-main);
  transition: all 0.2s ease;
}

.form-control::placeholder {
  color: rgba(148, 163, 184, 0.45);
  font-size: 0.85rem;
}

.form-control:focus {
  background: rgba(15, 23, 42, 0.8) !important;
  border-color: var(--primary) !important;
  box-shadow: 0 0 0 3px rgba(0, 212, 255, 0.08);
  color: var(--text-bright) !important;
  outline: none;
}

select.form-control {
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
  padding-right: 38px;
  background-image: url("data:image/svg+xml,%3Csvg fill='%2300d4ff' viewBox='0 0 24 24' width='20' height='20' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M7 10l5 5 5-5z'/%3E%3C/svg%3E") !important;
  background-repeat: no-repeat !important;
  background-position: right 10px center !important;
  background-size: 18px !important;
  cursor: pointer;
}

select.form-control option,
select.form-control optgroup {
  background-color: #0f172a;
  color: var(--text);
}

select.form-control option:checked {
  background-color: rgba(0, 212, 255, 0.15);
}

select.form-control:hover {
  border-color: rgba(0, 212, 255, 0.3);
  transform: none;
  box-shadow: none;
}

/* -- Checkbox -- */
.form-check-label a {
  color: var(--primary);
  text-decoration: none;
  border-bottom: 1px dotted rgba(0, 212, 255, 0.4);
}

.form-check-label a:hover {
  color: var(--text-bright);
}

/* -- Submit -- */
.btn-submit {
  display: block;
  width: 100%;
  padding: 13px 28px;
  margin-top: 20px;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: var(--font-main);
  color: var(--bg-dark);
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border: none;
  border-radius: 10px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: all 0.3s ease;
  box-shadow: 0 4px 20px rgba(0, 212, 255, 0.15);
}

.btn-submit:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(0, 212, 255, 0.25);
}

/* -- Countdown -- */
.countdown-section {
  margin-top: 28px;
  text-align: center;
  padding: 22px 20px;
  background: rgba(0, 212, 255, 0.025);
  border-radius: 12px;
  border: 1px solid var(--border-subtle);
}

.countdown-label {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--primary);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 14px;
}

.countdown-timer {
  display: flex;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
}

.countdown-block {
  background: rgba(15, 23, 42, 0.7);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  padding: 10px 14px;
  min-width: 72px;
  text-align: center;
}

.countdown-block .num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text-bright);
  line-height: 1;
}

.countdown-block .lbl {
  display: block;
  font-size: 0.65rem;
  color: var(--text-muted);
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-top: 5px;
}

/* -- Footer -- */
.footer-pro {
  background: linear-gradient(180deg, rgba(10, 14, 26, 0.97), #060a14);
  padding: 44px 20px 28px;
  color: var(--text-muted);
  font-size: 0.88rem;
  border-top: 1px solid var(--border-subtle);
  position: relative;
  z-index: 3;
}

.footer-pro::before {
  content: '';
  position: absolute;
  top: 0;
  left: 15%;
  right: 15%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--primary), transparent);
}

.footer-pro .footer-logo {
  width: 44px;
  filter: drop-shadow(0 0 6px rgba(0, 212, 255, 0.2));
  transition: transform 0.3s ease;
}

.footer-pro .footer-logo:hover { transform: scale(1.06); }

.footer-pro .footer-title {
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--text-bright);
}

.footer-pro .footer-subtitle {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.footer-pro .footer-link a {
  color: var(--primary);
  font-weight: 500;
  text-decoration: none;
}

.footer-pro .footer-link a:hover { color: var(--text-bright); }

.footer-pro h6 {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--text);
}

.footer-pro ul li a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.84rem;
  transition: color 0.2s;
}

.footer-pro ul li a:hover { color: var(--primary); }
.footer-pro i { color: var(--primary); opacity: 0.7; }

.footer-copy {
  font-size: 0.75rem;
  color: rgba(148, 163, 184, 0.5);
  font-family: var(--font-mono);
}

.footer-credits {
  font-size: 0.8rem;
  color: rgba(148, 163, 184, 0.45);
}

.footer-credits a {
  color: var(--primary);
  text-decoration: none;
}

.footer-credits a:hover { color: var(--text-bright); }

/* Responsive */
@media (max-width: 768px) {
  .reg-card .card-body { padding: 20px 18px 28px; }
  .reg-card .card-header h3 { font-size: 1.05rem; }
  .countdown-block { min-width: 62px; padding: 8px 10px; }
  .countdown-block .num { font-size: 1.3rem; }
  .form-group { padding: 10px 10px; }
  select.form-control {
    background-image: none !important;
    padding-right: 14px !important;
  }
}

@media (max-width: 480px) {
  .reg-card .card-body { padding: 16px 14px 24px; }
  .reg-card .card-header { padding: 16px 14px; }
  .reg-card .card-header h3 { font-size: 0.95rem; }
  .countdown-block { min-width: 54px; padding: 6px 8px; }
  .countdown-block .num { font-size: 1.1rem; }
  .footer-pro { padding: 16px 12px; font-size: 0.75rem; }
  .form-control { font-size: max(0.88rem, 16px); min-height: 44px; }
}